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Eggtimer TRS Flight Computer User`s Manual

1. vV Flt 0 28 T Apogee 12 4 V FIt 0 28 Max Veloc 864 52 FIt 0 28 T Maxv 2 3 V FIt 0 28 Droaue Alt 7116 V FIt 0 28 Main Alt 496 vV e TAP to redisplay flight milestones e 28 e HOLD for 1 sec to exit to Flight Display summary Deployment Testin Main Menu Deploy Test e HOLD for 1 sec to select Deploy Test Tap to Exit e TAP to Ex1t to Main Menu e HOLD for 1 sec to select Deploy Test Test Drogue e TAP to change value e HOLD for 1 sec to select Deploy Test Test Main TAP to change value HOLD for 1 sec to select Test Main Poteet ee eran gt HOLD TO TEST e HOLD to select i E E E 53 Hold for 7 secs l to start test REWARNING TEST IN PROGRESS l e Beeps for 10 sec l e Channel fires V e Next screen Test Completed Eggtimer Halted Flight Display 34 59464 5 DM 116 96096 5832 Top Line e Latitude in the format programmed in your LCD s setup screen e of Satellites in view 5 in this example e A bar graph showing the quality of the fix data from 0 7 bars e The status of the Drogue and Main channels D Drogue on M Main on Bottom Line e Longitude in the format programmed in your LCD s setup screen e Real time AGL Altitude in feet changes to apogee at landing 54
2. At that point the Eggtimer TRS looks at your flight profile to determine what deployment channels to test and it does some internal tests as well If everything is OK it goes on to the Ready for Flight sequence indicated by a 10 second long beep When the Ready for Flight beep stops you will hear continuous chirping that indicates that altitude samples are being taken and saved to the pre LDA memory so the rocket may be launched at any time GPS and altitude data will start streaming to the data port and if you have an RF link you will see that data on your monitor or LCD display 27 The normal TRS flight display screen looks like this 34 59464 5 DM 116 96096 5832 The top line shows you e Latitude in the units that you chose when you programmed your LCD display e of Satellites in view 5 in this example e A bar graph showing the quality of the fix data from 0 7 bars e The status of the Drogue and Main channels If they have continuity the letter will be there if they do not it will be blank For example the DM means that both channels are live After your Drogue channel fires you will only see the M after the Main fires they will both be blank Note that the DM status is only displayed if there is an active radio signal from the TRS to the LCD If you lose the connection during a flight the DM will be replaced by a number from 0 99 with the number of seconds since the last
3. electrically isolated from each other through optoisolators This absolutely prevents a dead short on the deployment side from causing the computer to stop working resulting in a less than optimal recovery deployment Programming and status can be done wirelessly with the Eggfinder LCD receiver and you can also use it to review the milestones of your saved flights apogee main deployment altitude etc You can also check the status prior to launch and arm the deployment channels remotely other than the NAR TRA required deployment power disconnect switch you do not need to use a separate power switch If something is not right and a flight should not be attempted you will be alerted on the LCD display and by an audio alert and the Eggtimer TRS will not arm Programming can also be done using a standard VT100 ANSI serial terminal program connected to your computer with a USB serial cable Since there is no special software required you can use just about any computer running Windows Mac Linux or just about anything else you can come up with Flights can be downloaded to a standard CS V formatted file and can be imported into virtually any spreadsheet or data analysis program to produce flight graphs The firmware on the processor chip performs real time data analysis during flights to detect and report significant flight events such as launch apogee deployments and landing A software filter is used to ensure that noise doesn
4. experienced rocketeers and most importantly common sense Limited Warranty Eggtimer Rocketry warrants that all of the parts on the packing list of the Eggtimer TRS kit have been included and that they are all in working condition If you are missing something contact us immediately at support EggtimerRocketry com and we will send you whatever it is that you are missing If you are missing something really egregious like the PC board or the processor for example we may ask you to return the entire kit unbuilt we will send you a prepaid shipping label for this purpose We d especially like to see the packing list so we can figure out what went wrong so it doesn t happen again If your Eggtimer TRS does not work properly after assembly take a deep breath get out the magnifying glass and a good light and see if you have inadvertently created a solder bridge somewhere Chances are pretty good that you have or that you have installed a part incorrectly We are a very small company and we just don t have the resources to repair your board but we 5 will be more than happy to give you advice and we might be able to help you find your error if you send us some high resolution pictures to support EggtimerRocketry com We cannot take responsibility for your assembly techniques if you do not have experience building kits of this nature we recommend that you enlist some help Another reason for joining a rocketry club there is
5. not have the accuracy that you re going to get with a dedicated instrument You NEED a digital voltmeter in your tool box anyway if you don t have one run out to Radio Shack and buy one they re under 20 12 Using Your Eggtimer TRS with the Eggfinder LCD Receiver The Eggtimer TRS is designed to be used with the Eggfinder LCD receiver In addition to the same GPS coordinate functions that you get with an Egefinder TX transmitter you can also use the Eggfinder LCD to program your Eggtimer TRS flight settings check the status of the computer battery and the deployment channels test the deployment channels see the Appendix and during your flight display the real time altitude from the pressure sensor and the status of the deployment channels The Eggfinder LCD receiver actually acts as a dumb display terminal similar to the USB cable attached to the data port with a terminal program All of the data actually comes directly from the Eggtimer TRS nothing is stored or saved on the LCD receiver itself If you change something and get a confirmation it s coming directly from the Eggtimer TRS unit so you can be sure that it really did get changed Note Eggfinder LCD software version 1 09d is the minimum release that supports programming the Eggtimer TRS Earlier versions will display the GPS coordinates but they will not show the altitude or deployment channel status in flight If your Eggfinder LCD receiver has an earlier vers
6. rail turn on the deployment power then choose Save and FLY This keeps the TRS disarmed until you re safely on the pad If you select one of the FLY options before you turn on the deployment power it s just going to keep beeping until you turn on the deployment power While this is a safe mode you don t want to take your rocket to the RSO table with it making a lot of noise you re going to get a lot of funny looks and if the RSO isn t familiar with the TRS they might think that it s actually armed when in fact it s quite the opposite Once the beeping stops because you ve turned the deployment power on you have to HOLD the button down for at least 7 seconds to start a flight This is so you can t accidentally start the flight sequence by accidentally tapping the button once you start the flight sequence you can t interrupt it without either resetting the TRS or turning off the power LO rz Programming Your Eggtimer TRS with the USB Cable The Eggtimer TRS can be programmed from just about any USB compatible computer using a USB TTL serial data cable This cable has the interface circuitry imbedded in the USB connector so it doesn t use up any board space or power on the Eggtimer It uses a Prolific PL 2303 serial interface chip you will need to install the drivers for it before you can connect it to your Eggtimer TRS See the Eggtimer Rocketry web site for the appropriate drivers The interface
7. they point to the altitude and time at which specific events in the flight have occurred For example the LowV marker shows that the Low Velocity event the end of Mach Lockout after 1 second of lt 100 ft sec velocity has been detected occurred at about 17 seconds and 4400 feet You can clearly see that the rocket hits peak altitude at about 18 seconds and maximum velocity at about 3 seconds Note that the velocity graph is jaggedy compared to the altitude graph this is due to the aforementioned issues with deriving velocity from barometric pressure The important thing is that you can see clearly where the velocity peaks then drops sharply this is where the motor burned out and aero drag immediately started to slow the rocket You can also see where the drogue ejection charge fired about a second after apogee and the rocket starts to slow The CHA main channel fired at about 94 seconds at about 500 237 lt Building Your Rocket to Use the Eggtimer Mounting First things first the Cardinal Rule of tracker mounting is KEEP THE ANTENNA AWAY FROM METAL OBJECTS More on this later In order to use your Eggtimer TRS with a rocket it will need to be properly mounted and secured The Eggtimer TRS is designed to be used with just about any rocket with a 1 35 dia BT 55 or 38mm payload bay so any rocket that will take an egg will easily take the Eggtimer TRS However there is some preparation that will be need to be done t
8. KNOW what the settings are you don t have to remember what you think they might have been when you flew a month ago If you are in any programming screen and don t hit any buttons you will get a short beep every 15 seconds to tell you that the TRS is still communicating with your LCD display If you stop hearing the beeps that means that for some reason your TRS is no longer communicating you should power cycle both of them and re pair them To enter the Display Change Settings menu PRESS the button for about 1 second To go to the NEXT menu item TAP the button you will see this menu Main Menu Display Flights This is the Flight Display menu It allows you to get flight milestone data for all 32 flights starting from the most recent one and working backwards to the oldest You can review information such as the apogee altitude maximum velocity etc Note that it is not as comprehensive as the download that you can get with the USB data cable it s designed to be a quick review of your flights PRESS the button to review your flights and see the second on the Flight Display for more details TAP the button to go to the next menu you ll see this menu Main Menu Deploy Test This is the deployment test menu One of the nice things about using the Eggfinder LCD receiver is that you can do a full deployment test with your deployment charges remotely from a safe distance There are a number of safety fea
9. LowV Apogee N O Drogue Main 0 0 0 0 0 0 0 0 0 0 0 50 12 240 2 4 48 0 0 0 0 0 0 100 20 160 5 92 70 4 150 25 100 9 74 76 32 200 29 80 13 59 77 06 250 34 100 17 67 81 6 300 46 240 23 34 113 350 59 260 30 47 142 400 77 360 39 78 186 1 450 94 340 50 62 216 9 500 129 700 66 3 313 52 550 153 480 83 64 346 81 600 181 560 103 11 389 4 650 196 300 121 69 371 5 700 203 140 137 95 325 2 750 206 60 151 56 272 2 etc The first data field is the elapsed time in milliseconds the second data field is the altitude in feet and the third data field is the velocity in ft sec The two F fields are filtered data the rest of the values are event markers that show when various flight milestones have been reached After you close the file you can open it with the data analysis program of your choice For example if you import it into Excel you can graph Time vs Alt and Time vs Velocity See our web site www eggtimerrocketry com for step by step instructions on how to do this it s not difficult once you get the hang of it You can also import the CSV data into statistical software packages although this is beyond the scope of what we re doing here 36 An Excel scatter graph from this data looks something like this 60000 80000 100000 120000 140000 The FAIt trace is altitude time the FVeloc trace is the filtered altitude time The other spikes are event markers
10. Main Menu This is because you MUST review the settings before you can start a flight so if you ve changed something then the implication is that you re either ready to start a flight or you re changing the settings for a flight at some later time To save or discard your settings PRESS the button for at least 1 second from Save Options The screens that you can select look like this as usual TAP the button to cycle through them and PRESS the button for at least 1 second to make your selection Save Options FLY w o Saving Save Options Save and FLY Save Options Save and HALT Save Options Return wo Save If you select Return wo Save any changes you made will be discarded and you will be returned to the Main Menu This is what you d do if you were simply reviewing the existing settings and wanted to go back to the menu If you select one of the FLY menus you ll get the Status Display screen as it checks the deployment channel status If everything is OK it will sit there as long as you want it to until you HOLD the button for at least 7 seconds then you ll hear a long tone as the flight sequence begins 20 Typically what you will most likely do is to change your settings at your work table with the deployment power off and leave it on the Save Options menu take it to the RSO to get it checked off cycle through the settings to double check them after you put the rocket on the rod
11. Settings 9600 baud 8 bits 1 stop bit no parity no handshaking Emulation ANSI VT100 Monitor Mode To enter Monitor Mode connect the terminal cable start your terminal program and hold the Button down while powering on the Eggtimer TRS You will see a MON gt prompt on your terminal screen Hit the one character monitor code to perform the function some of them also require that you press the Button to start them Monitor Codes 0 Dump LAST USED memory page to data port in CSV format A Dump ALL memory pages to data port in CSV format this takes awhile E Dump the processor s EEPROM to data port in CSV format for tech support use M Fire Main channel for 2 seconds you need to press the Button to fire the channel D Fire Drogue channel for 2 seconds you need to press the Button to fire the channel Programming Screen Eggtimer TRS 1 4N Flight Settings MY EGGTIMER T 23 50 P 97804 00 A 1 Drogue lt 0 OFF 1 Nose Over 2 Backup gt A 975 39 B 700 Main Altitude lt 100 2000 by 50 O OFF gt Main 1 Drogue 1 Batt 7 74 900 Frequency Ctrl F to Change 0 ID Code Options Letter to Change ESC to Save 48 e To update the real time readings on the right hand side press the ENTER key e To change values press the LETTER of the option use to change the values hit ENTER to accept value e To accept settings and save hit the ESC key the buzzer will start beeping slowly Eggtimer is now in Halted mo
12. can introduce errors into the velocity reading angle of attack wind errors in the pressure readings due to aerodynamic influences and time differences If you measure the launch angle prior to launch you can calculate this error although anything such as wind what makes the rocket deviate from a straight vertical path will pretty much negate this compensation unless you had set the angle to a really high value over 15 If the pressure ports in your payload bay aren t sized properly this can introduce an error particularly if they re too big and you have two of them opposite each other you ll get a crossflow through the payload bay which makes the pressure readings very noisy Finally differences in the processor s timing may introduce errors although the readings are taking at relatively precise intervals so it s going to be very small The good news is that the magnitude of these errors tend to be proportionate to velocity as the rocket ascends so they respond well to being filtered with mathematical noise filters We use a variation of an exponential moving average filter to smooth out this noise so transition to supersonic speeds and back can be detected with relatively good accuracy 29 Mach Transition As your motor continues to burn and the velocity increases if the velocity exceeds 800 ft sec aerodynamic shock wave pressure buildup can fool the pressure sensor into thinking that the rocket is descendi
13. computer side is suspended the GPS module will still be running and tracking satellites and the transmitter will be sending out your NMEA positional data When the reset switch is opened the Eggtimer TRS begins the startup sequence You will hear a continuous slow beep beep sound as it tries to pair up with an Eggfinder LCD receiver If it can t find one you ll hear a faster beep beep for another 30 seconds as the programming screen is displayed through the data port and it waits for input from the data port If it doesn t see anything you must be on the pad waiting to fly so you II hear a long beep and after approximately 10 more seconds the Eggtimer TRS begins taking altitude readings and recording and chirps until launch to let you know that it s ready for flight If you are NOT going to be using an Eggfinder LCD display receiver we recommend that you use some kind of switch or jumper to short the Reset pads while at the RSO table and on the pad prior to launch This acts as the equivalent of an ON OFF switch but does not power off the GPS module This is important because you don t want to turn off power to the GPS or it will lose its satellite data and have to reacquire the fix which may take 5 minutes or more to reacquire in some rare cases If you ARE using an Eggfinder LCD receiver the flight sequence won t start until you arm it remotely AND both deployment channels have passed the self test so yo
14. flight summary download if this happens 30 When Nose Over is detected the Eggtimer TRS begins using the Descent Samples value for altitude sampling This setting is very low 2 samples sec As the rocket descends when the altitude drops below the Main deployment altitude the Main channel is triggered for 2 seconds At this point your Main chute should pop out to thundering applause and a hearty round of high fives all around On the Ground The Eggtimer TRS detects that your rocket is on the ground when the AGL altitude is below 30 feet for over 5 seconds Unless you launched from a hill it s unlikely that your landing altitude will be lower than that by a full 5 seconds times the descent rate which is typically about 20 feet sec for a main chute That works out to a landing altitude 100 below your launch altitude which would be unusual What is more likely is that it won t be able to figure out that you ve landed generally because your rocket landed on high ground or a tree If that happens it will continue to record altitude samples at the Descent Samples setting until it runs out of flight memory When that happens it will call it a flight Once on the ground the Eggtimer TRS will send out the apogee through the radio until reset It also sends out your GPS coordinates so if your rocket gets dragged on the by the parachute by the wind or picked up and returned to the range you ll be able to get an updated fix
15. gov cgi bin text idx SID adb12f74b498e43ec453f7899d9df0fd amp node 47 1 0 1 1 16 amp rgn div5 Hope RF HM TRP Documentation FCC test documentation http www hoperf com upload rf HM TRP 915 20dBm FCC pdf FAA Regulations for Amateur Rocketry Part 101 http www ecfr gov cgi bin text idx c ecfr amp ren div5 amp view text amp node 14 2 0 1 3 15 amp idno 14 Before You Start e Go to our web site at www Eggtimerrocketry com and download the latest Release Notes e Go to our web site at www Eggtimerrocketry com and download the latest Assembly and Users guides e Read them thoroughly before starting it will save you some grief later we promise m w w w w w w OOOO OOOO a a a a a a a a a Thanks for buying an Eggtimer TRS Flight Computer The Eggtimer TRS is a Total Recovery System for hobby rocketry Like other flight computers it can deploy two parachutes to bring your rocket safely to the ground and you can record flight statistics and download your flight profile to a computer to get a nice graph of your flight It also uses a GPS module and a 900 MHz license free transmitter to broadcast your rocket s location in real time to a computer or tablet or the Eggfinder LCD handheld receiver With appropriate GPS tracking software which is available for free on the Internet you can actually track your rocket in flight and ultimately find out exactly where it landed You can program the flight settings with
16. if y ou have your Egefinder LCD receiver with you It also acts as a verification that you had a successful flight but getting your rocket back in one piece pretty much told you that didn t it After the Flight Once you ve noted the maximum altitude so you can brag about it to your friends you should TURN OFF the deployment batteries It s OK to leave the Eggtimer TRS on until you get back to the range Gather your rocket up and take it back to your work table get a can mug bottle of your favorite beverage then you are ready to download the data 31 Displaying Your Flights with the Eggfinder LCD Receiver One of the nice things about having an Eggfinder LCD receiver with the TRS is that you can review your flights without having to break out the laptop and the USB cable You can t get as much data as you can from the cable since your LCD receiver obviously can t create graphs or give you detailed flight statistics but you can get a quick display of your apogee maximum velocity and a few other flight milestones To display your flights pair up your Eggtimer TRS with your Eggfinder LCD receiver From the Main Menu TAP the button until you get to the Flight Display menu Main Menu Display Flights ei PRESS the button for at least 1 second to display the last flight Flt 0 28 A 7128 V 864 Flights are numbered starting from zero your last flight and incrementing by one to let you know how old the fligh
17. is a simple text terminal VT100 ANSI compatible No fancy GUI graphics but it s fast and easy to use and free terminal emulator software is readily available for every OS known to man We like TeraTerm and PuTTY but any emulator will do however to download flight data you need to be able to capture the data stream to a file so make sure your terminal program supports this If it doesn t you can get around it by doing a Copy of the text that gets output to your screen and doing a Paste into a text editor such as Notepad If you do not already have a suitable terminal program or you need the USB Serial driver for the cable go to www eggtimerrocketry com click on the Links tab and you will be directed to a suitable download location Note that we try to support non Windows operating systems since the Eggtimer TRS is OS agnostic however we re Windows geeks so we can t guarantee that we ve had a chance to try every possible configuration especially with Linux Before you try flying your Eggtimer TRS we recommend that you play around with the programming screens on your workbench until you are comfortable with it You can t hurt anything and if you totally mess up the memory you can always do a Master Reset to clear out all of your experimental values To get to the Eggtimer TRS terminal menu screen be sure that the power on the Eggtimer TRS is OFF Connect the headers of the USB serial cable to your Eggtimer TRS as fol
18. programming mode If it doesn t see a cable within 30 seconds it assumes that you re sitting on the pad waiting to launch so it starts the launch sequence When you first turn on your Eggtimer TRS and your Eggfinder LCD receiver which should be done within 45 seconds so the pairing doesn t time out you will see this screen Eggfinder RX LCD version 1 09d ay ice This is the standard Eggtinder LCD welcome screen and it will be displayed for about 5 seconds You will then see this screen Status 915 0 GPS D AIt F 6 4V This is the Eggfinder LCD status screen that tells you what your Eggfinder LCD receiver s current settings and battery voltage are If you hold the button down for about 2 seconds and release it you can change them however you should not do that while you are trying to pair with your Eggtimer TRS unit See the Instructions in the Eggfinder LCD Users Guide for more details Assuming that you do nothing after about 10 seconds you will see this screen Waiting for Sync This tells you that the Eggfinder LCD is waiting to hear the beacon from the Eggtimer TRS unit After a few seconds you should see this screen Eggtimer TRS 4N MY EGGTIMER TRS This screen is your confirmation that the two units have paired up It shows you the software version of the Eggtimer TRS and the Device Name that you gave the unit in the Frequency Setup screen More on that later The Device Name is your confirm
19. replace their deployment battery after EVERY flight regardless of the voltage or the current draw being used With a 9v Alkaline battery and a Quest Q2G2 igniter this may be overkill but for smaller batteries such as an A23 12v battery it may be a really good idea Compared to the cost of the rocket motor Eggtimer TRS and last but not least your time a few dollars per launch to ensure that you get a good deployment is cheap Of course if you re using a rechargeable LiPo battery this probably doesn t matter all that much the amount of current that a LiPo will put out is huge compared to the requirements of most deployment igniters ematches Just make sure that you test it before every flight and keep it charged up 6 If you are using a pyro ejection charge you MUST have an external deployment power switch to disarm the deployment power until shortly before launch This is a Tripoli and NAR safety requirement and is just good common sense too You can pair up your Eggtimer TRS unit with your Eggfinder LCD receiver at your prep table leaving the deployment power OFF until you have the rocket on the rod rail then turn it on right before you start the flight sequence from your LCD receiver If you are NOT using an Eggfinder LCD receiver to arm the Eggtimer TRS you should shunt the Reset terminals to put the Eggtimer TRS in hold mode then release the Reset shunt and turn on the deployment power on the rod rail to start the flight
20. sequence This will keep power to the GPS module so you don t lose your fix We DO NOT recommend powering down the Eggtimer TRS power until you re at the pad like you would do with other flight computers The GPS needs to stay powered to maintain the fix We ve seen the results of launching without a fix the Lost Patrol may still be looking for that rocket 40 Air Pressure Ports For the altimeter to work properly there must be an undisturbed exposure to the outside air pressure This is a little trickier than it sounds because the air is whizzing by the rocket at several hundred feet per second during flight so as you may remember from Bernoulli s principle in Physics this is going to cause the pressure at that location to drop if the pressure cannot be equalized The trick is to make the air pressure ports large enough so that sufficient air can enter the payload bay but not so small that it drops with air velocity If you make the ports too large then crossflow air currents can disturb the airflow and your readings will be very noisy during the boost and coast phases when the rocket is moving at high speed There has been a lot written about sizing air pressure ports for model rocket altimeters but most of the literature agrees that the total area need to be about 1 500 of the volume of the payload bay For example a 3 rocket with a 9 payload bay has about 63 5 square inches of volume so the total area of the por
21. t affect flight events a velocity profile algorithm is used to prevent deployments due to the pressure changes that occur during mach transition with ae a no user intervention or programming required This is the same logic that has been proven in the classic Eggtimer for hundreds if not thousands of flights Getting to know your Eggtimer TRS Although the Eggtimer TRS seems relatively simple you will want to familiarize yourself with it BEFORE you install it in a rocket and certainly before you try flying it There are several set of solder pads for making connections to the board and some indicators BATT Two solder pads marked and for connecting the Eggtimer battery We recommend using a 2S 7 4V LiPo battery but any battery from 4 5v 20v can technically be used Average current draw with the GPS running is about 70 ma but there may be peaks of about 200 ma for a short time while the GPS module acquires satellites DPWR Two solder pads marked and for connecting the deployment power battery You can use just about any battery from 3v 60v the battery choice is dependent mostly on the requirements of your deployment igniter Most igniters work well with a 2S 7 4V LiPo similar to what we recommend for the main power We strongly recommend that you use a switch in line with the terminal of your battery to disable deployment power until your rocket is on the rod rail MAIN Two solder p
22. will automatically associate the data type with the right program i e Notepad or Notepad if you have it if you do not we recommend that you get it you ll never use Notepad again for the summary data and Excel for the CS V formatted detail file Be sure to use csv as the extension for the detail data if you want Windows to recognize it as a CSV file when you open it For example here is some actual flight data taken from a Giant Leap Rocketry Escape Velocity on a CTI 5 grain J290 Flight Summary Eggtimer TRS 1 4N Flight Settings Main Altitude lt 50 2000 by 50 0 0FF gt 500 Drogue lt l Normal 2 Backup 0 OFF gt 0 Frequency Ctrl F to change 915 ID Code 0 REV A4 Test BD ASL Alt 2703 ft Base Temp 42 00 C Beep Code 0 Last Flight Phase 9 Flight Time 116 000 secs Apogee 4525 ft T Apogee 17 000 secs Max Velocity 677 ft sec T Max Velocity 1 000 secs Avg Accel Max veloc 466 90 ft sec2 G 14 50 LDA 203 ft Time LDA 0 700 secs Altitude Unlock 4426 ft T Unlock 14 00 secs Altitude Nose Over 4447 ft T Nose Over 18 00 secs Altitude Main Deploy 489 ft T Main Deploy 94 000 secs The first part of the summary shows you the flight settings that were used the second part shows you the elapsed time and altitude for each major flight event It also shows you the measured ASL altitude of the launch site the temperature the beep code i
23. E 16 1261 407 F 15 229 114 G 14 1778 394 H 13 1352 376 I 12 0 0 J 11 0 0 K 10 0 0 L 12 0 0 M 11 0 0 N 10 0 0 o 12 0 0 P 11 0 0 The most recent 16 flights are displayed on the first screen To toggle between the two 16 flight display screens hit the or key Flights that have 0 in the Apogee and Max Veloc columns are unused memory locations and or test flights when you have started the flight sequence but have not launched like you might do if you were testing settings To select a flight to display hit the letter key for that flight from A P Case doesn t matter you can hit a p too For example if you wanted to download the data for the flight at 1346 you would hit the D key From this display you can see that there are some null flights After you hit the letter for the flight you will be prompted to hit the button to start the download At this point you should go into your terminal program and select the appropriate option for dumping the text to a file Since the summary data and the detail data are downloaded in two separate 34 ee operations you can save them separately by simply closing the buffer after downloading the summary data then opening it again for the detail data We recommend that you use a file name like Flight 2014 08 26 No1 txt for the summary data and Flight 2014 08 26 Nol csv for the detail data This way when you open up the data files you
24. Egetimer TRS Flight Computer User s Manual Firmware Release 1 4N Board RevA5 2015 Eggtimer Rocketry All Rights Reserved Important Regulatory Information This device complies with Part 15 of the FCC Rules Operation is subject to the following two conditions 1 this device may not cause harmful interference and 2 this device must accept any interference received including interference that may cause undesired operation It is intended to be used ONLY for educational and experimental use in Model Rockets and Class II III amateur High Power Rockets which are classified as aircraft by the Federal Aircraft Administration CFR 14 101 25 and which must by FAA and NFPA regulations be operated at least 1 500 away from any populated buildings Although unlikely this device may cause interference with consumer devices that run on the unlicensed 902 928 MHz band and therefore must not be used in residential areas The Eggtimer TRS uses RF modules in the 902 928 MHz ISM band manufactured by Hope RF model HM TRP 915 They are intended to be used in the United States or other countries with similar spectral regulatory rules These modules have been tested by Hope RF to be compliant with the FCC Part 15 regulations for non licensed intentional emitters and as such have been permitted to be imported into the US However Hope RF at the time of this document has not obtained formal certification with the FCC As a hobby kit desig
25. Eggfinder LCD receiver with it you will be sure that it s YOUR device that you re looking at Note If you change the frequency and or ID Code of your Eggtimer TRS you ll need to change it on your Eggfinder LCD receiver as well If you are using an Eggfinder RX dongle receiver it will be a fixed frequency with an ID Code of zero To get to the Eggtimer TRS frequency programming screen go to the Eggtimer TRS Flight Settings menu by connecting the cable to your laptop starting your terminal program and turning on the Eggtimer TRS When you see the screen hit the ENTER key to stop the beeping and let the Eggtimer TRS know that you re programming it From the Flight Settings screen press the CTRL and F keys simultaneously You will see this screen Eggtimer TRS 1 4N Frequency Programming A 915 Frequency lt 909 925 by 2 gt B 0 ID Code lt 0 7 gt C Device Name MY DEVICE A C Change ESC Save Press the letter of the parameter that you wish to change For Frequency and ID Code you cycle through the values by using the and keys the key goes UP to the next value the key goes DOWN to the previous value When you see the value that you want hit the ENTER key The Device Name is a 16 character freeform text field it accepts A Z capitals only 0 9 and spaces You can use the BACKSPACE or DEL keys to back up a character When you re done hit the ENTER key When you are satisfied with al
26. NMEA formatted GPS tracking data that can be picked up by an Eggfinder RX dongle or Eggfinder LCD handheld display receiver and the coordinates can be used to take you right to where your rocket landed Up to 72 Eggtimer TRS units can be operated simultaneously by simply changing the center frequency and ID code and you can name your device so you re sure that it s yours when you pair it with your Eggfinder LCD receiver The Eggtimer TRS is designed to be used with FAA Class I II and III amateur hobby rockets The only limitation is how high the rocket is expected to go we recommend it for flights up to about 10 000 with the included wire antenna and about 20 000 with external antennas The Main deployment channel is programmable so that it may be triggered at a fixed altitude from 100 1200 feet The Drogue output can be deployed just after apogee or it can be used as a backup channel so that it deploys two seconds after apogee This allows the Eggtimer TRS to be used as a backup deployment altimeter in projects that require redundant recovery systems The deployment channels are capable of triggering common ematches such as the ones made by MJG and J Tek using an appropriate battery such as a small 7 4v LiPo pack You can also use a low current igniter such as a Quest Q2G2 with a single 3 7v LiPo battery Like the classic Eggtimer it features separate batteries for the computer and deployment circuits which are 100
27. S module searches for satellites Most of the power draw in the Eggtimer TRS is from the GPS REF side the processor side only draws about 8 mA Like a cell phone you will get better battery life with a stronger signal so you may find that the battery life varies significantly from time to time since the GPS will draw more current if there are fewer satellites in view 10 We recommend using a 2S 7 4V LiPo battery at least 350 mAH This will run the Eggtimer TRS for at least 5 hours continuously If you have a bigger rocket and have room for a bigger battery a 800 mAH or 1000 mAH battery will easily run your Eggtimer TRS for a whole day possibly a whole flying weekend You CAN use a battery as small as 200 mAH if you have a small rocket and know that it s not going to be on for more than 2 hours we ve done that with rockets using 24mm and 29mm motors but you have to recognize the limitations and make sure you charge it before every flight which you should do anyway We do NOT recommend using a 9V alkaline battery to power the Eggtimer TRS The Eggtimer TRS draws too much current and you will find that your battery is only going to last for 2 hours if that A 350 mah 2S 7 4v LiPo is about the same size and weight and can source much more current for much longer For deployment power your battery is largely going to be dictated by the requirements of your deployment igniter Most igniters that are commonly used for deployment
28. This is the time to maximum velocity FIt 0 28 Droaue Alt 7116 This is the altitude that the Drogue fired at It will only be displayed if the Drogue channel was enabled FIt 0 28 Main Alt 496 This is the altitude that the Main fired at It will only be displayed if the Main channel was enabled FIt 0 28 Exit To exit the flight milestones display PRESS the button for at least 1 second from this display You will be returned to the Flight Status display to exit to the Main Menu from there HOLD the button down for at least 7 seconds Bee Downloading Flight Data with the Data Cable The Eggtimer TRS records your last 32 flights into its flight memory reporting three types of data Flight Settings All of the settings on the Flight Settings menu Summary Data Stuff like apogee length of flight maximum velocity etc Detail Data A CSV formatted data stream with elapsed time altitude and velocity You may not be able to use all 32 flights worth of data because if you abort a flight you are going to get a null flight that consists only of the Flight Settings with no data You will also get this if you have it on the bench and pass through the programming screens To enter the Flight Display screen hit the key at the Flight Settings screen You will see something that looks like this Saved Flight Summary Page Apogee Max Veloc A 20 4525 677 B 19 1623 361 c 18 0 0 D 17 1736 537
29. a tendency to break after being bent a few times These breaks can be a pain to find because they are typically inside the insulator jacket where you can t see them To prevent them we recommend that you zip tie the wires to the sled to strain relieve them If you use stranded wire you MUST TWIST AND TIN THE WIRES BEFORE SOLDERING TO THE BOARD This is to prevent stray whiskers of wire strands from coming loose and bridging pads or breaking off and landing on the board in some random place We ve seen the results of this happening it s not pretty and they can be very hard to find if they lodge underneath the processor chip or in some other hidden spot on the board All that being said you CAN install 150 3 81mm screw terminal blocks the holes are spaced for two sets of 4 terminal blocks We know that a lot of you out there really like the convenience of terminal blocks so we give you the option the kit does not include the terminal blocks however If you do use terminal blocks make sure that you check the screws before every flight so you can be sure that the wires don t work loose We also strongly recommend that you zip tie the wires exiting from the terminal blocks to your AV sled to provide strain relief for the wires We recommend that you put a small loop in the wires just past the terminal block and zip tie the loop to the sled so that any tension on the wires will tend to tighten the loop rather than pulling on th
30. ads for connecting an electric match or other low to medium current device Deployment altitude is programmable from 100 1 200 ft or it may be disabled if not used Maximum sustained current is 2A with peaks up to 8A DROG Two solder pads for connecting an electric match or other low to medium current device This channel may be used for a drogue chute to slow down the computer at apogee or it may be disabled if not used Data Port 3 pin TTL compatible header connector for connecting the USB serial data cable for programming and downloading data PWR RED LED that comes on when power is connected to the computer side Buzzer Beeps out status warnings altitude and other important notifications 1S Amber LED that blinks once per second when the GPS has acquired enough satellites to get a good fix This will occur usually if it sees at least four satellites See the section on Using the Eggtimer TRS with the Eggfinder LCD Receiver for more details Reset Pads RST When shorted the Reset terminals put the Eggtimer TRS on hold i e resets it so that it does nothing When it is in reset mode all outputs are held low so this is the safe mode when multiple deployment systems are used they cannot be triggered while the Eggtimer TRS is reset This can be used to disable Eggtimer TRS while it s sitting on the pad for a long time and can be released shortly before launch Although the flight
31. ast two preferably four 4 40 screws and nylon washers and use nylon washers on the top of the board if you are using metal screws You can use self tapping screws if the sled is wood but we recommend that you put a dab of CA glue in the holes to keep the screws from coming loose You can also use a small strip of 4 plywood to stand off the board If you use machine screws put a dab of Loctite on the threads before you install the nuts or use Nylock type nuts You can also use nylon screws they are a little lighter but they re more expensive too NEVER use Velcro to mount your Eggtimer TRS it will generate static electricity when you remove it and you may damage your Eggtimer TRS permanently OK remember the Cardinal Rule What this means is THAT YOU CANNOT MOUNT THE EGGTIMER TRS IN AN AV BAY IF YOU HAVE ALLTHREADS RUNNING THROUGH IT OK so all of the AV bays that you ve ever build are held together with allthreads how are you going to put an Eggtimer TRS into them The answer is simple just mount the antenna 38 OUTSIDE of the AV bay away from the allthreads To do that you will need to install an RP SMA connector instead of the wire antenna and you may need to get a short RP SMA male female cable to bring the connector outside Simply use the cable to bring the connector outside screw your antenna into it rubber duckies work well for this and wrap the cable antenna around your shock cord with some duct tape You n
32. ation that it s YOUR Eggtimer TRS that it s paired up with and not somebody else s Since there are 72 possible frequency ID combinations it s unlikely that anyone else would be on yours unless neither of you changed it from the default At this point the two are in sync tap the button to continue 14 The Eggtimer TRS Eggfinder LCD Interface The Eggfinder LCD receiver has a two line x 16 character LCD display and one button When in terminal mode paired with an Eggtimer TRS the display generally shows you what is being displayed changed on the top line and the current value on the bottom line The button has different functions depending on the menu but in all cases there are three different types of button presses TAP Clicking the button like you would if it was a computer mouse button PRESS Holding the button down for about 1 second then releasing it like a doorbell HOLD Holding the button down for at least 7 seconds then releasing it In general a TAP is used to go to the next menu or item a PRESS is used to select an item so that you can change it or display more information about it and a HOLD is used for either exiting out to the Main Menu i e from Flight Display or to confirm a function that does something fairly drastic like a deployment test When you TAP the button you will hear a short click When you PRESS the button you will hear a beep When you HOLD the button the sound y
33. ble check your flight settings then select SAVE and FLY eCheck the status on the LCD receiver If it beeps and flashes turn off the deployment power reset the computer take it off the rail and go back to the table and check your deployment igniter The Eggfinder LCD will begin beeping the display will start showing the GPS coordinates after a few seconds you ll see the altitude go from your ASL altitude to zero and you re good to fly e Hook up your motor igniter get back to the flight line and e Move to the safety area and watch your creation blast into the sky as the LCO hits the button If You Get an Error Tone Carefully approach the rocket TURN OFF the deployment battery power Disconnect the motor igniter from the launcher 26 Count the number of beeps to see what caused the error there may be more than one error Take the rocket off the rod rail open up the payload bay disconnect all batteries and fix the failed condition Then you can start all over having hopefully learned one more thing to check in the future You can see that if you re doing multiple deployments it s a lot more involved than just stuffing some wadding and the parachute into the tube popping in the motor and hooking up the igniter Multiple deployments require discipline in order to make them work reliably we ve seen way more than our share of failed deployments on everything from a small mid power E size rocket all the way
34. de e To perform a Master Reset clearing all flight memory and resetting to initial settings hit CTRL and Y then hold button for 10 seconds to confirm You should only need to do this once unless otherwise instructed e To change Frequency ID Code Device Name hit CTRL and F Navigation is the same as the Flight Settings screen Flight Display e To enter Flight Display mode press the key from the Programming Screen Eggtimer TRS 1 4N Saved Flight Summary Page Apogee Max Veloc A 20 4525 677 B 19 1623 361 c 18 0 0 D 17 1736 537 E 16 1261 407 F 15 229 114 G 14 1778 394 H 13 1352 376 I 12 0 0 J 11 0 0 K 10 0 0 L 12 0 0 M 11 0 0 N 10 0 0 o 12 0 0 P 11 0 0 e To toggle the pages from the first 16 flights to the second 16 flights press the or keys e To select the flight to download press the LETTER of the flight i e G for the flight with an apogee of 1623 feet To download the Flight Summary Data e Open the capture buffer in your terminal program see your terminal emulator s documentation e Press the Button to download the summary data in TXT format e Close the capture buffer in your terminal program and save it to your computer as a TXT file The Eggtimer TRS is now ready to download the Flight Detail data To download the Flight Detail data e Open the capture buffer in your terminal program see your terminal emulator s documentation e Press the Button to download the detail data in CSV
35. e ends in the terminal block Eggtimer TRS Battery Options There are actually two battery connections for the Eggtimer TRS One for the computer side and one for the deployment side They are electrically isolated from each other via optoisolators they do not even share acommon ground This is different from most other flight controllers on the market which typically use a single battery for both the computer and the deployment side The reason that we do this is to provide 100 immunity from any power issues on the deployment side from interfering with the processor s operation If you have a dead short on the deployment side even if the current surge was enough to destroy an output transistor it would have no effect on the processor and GPS you would still get a GPS feed and the processor would continue to log flight data and possibly continue with deployment of the other channel Brownouts are basically impossible It IS possible to operate the Eggtimer TRS with a single battery but we recommend that you only do that with very low current igniters such as a Quest Q2G2 or of course if you re not doing deployments You ll need to be a little careful with your battery choice more on that below Of course you give up the brownout protection if you do that so be careful The computer side of the Eggtimer TRS will run on anything from 4 5V 30V Current draw is about 80 mA continuous with a startup peak of about 200 mA as the GP
36. eed to strain relieve the cable so that it can t get pulled leave a little slack and zip tie the end to the shock cord mount Alternatively you can get a long RP SMA female edge connector one that s designed for bulkhead mounting and screw it to the AV bay bulkhead You ll need to rigidly mount the sled on that bulkhead you don t want it moving but if the bolts on the allthreads that hold the AV bay together are removed from the other side then that won t be a problem If you go this way make sure that the antenna can t be damaged by the shock cord whipping around it s probably better if you mount the antenna on the drogue side since there s invariably a lot more room to work with and the deployment of the drogue is usually somewhat softer than the main Batteries can be mounted in several ways Small zip ties work well so does double sticky foam tape for LIGHT batteries like 200 mah LiPo batteries for example If it s a rechargeable battery and you don t expect to remove it a dab of epoxy works too Do NOT use double sticky Velcro it WILL come loose in flight and is a magnet for static electricity No matter how you mount the batteries make sure that they can t work loose during flight That would be bad you could lose your deployment power AND your GPS feed Multiple Deployment Hints 1 ALWAYS weigh your completed rocket with all batteries and the motor that you plan on using determine the CG and run it
37. either a USB data cable or wirelessly with an Eggfinder LCD handheld receiver Like other Eggtimer Rocketry products we sell it as a kit to keep costs down and provide an outstanding value This means that you have to do a little work of course but considering that most hobby rocketeers who would use our products have some degree of electronics expertise this should not be much of an impediment If you do not have any experience soldering kits or working with small electronic projects we recommend that you ask around chances are that somebody in your rocketry club would be more than happy to assist you for a small bribe beverages work well The Eggtimer TRS works in conjunction with the Eggfinder receivers either the Eggfinder RX dongle receiver that plugs into the USB port of your computer or the Eggfinder LCD handheld receiver that displays GPS coordinates and altitude in real time during your flight Whichever one you use we recommend that you build the Eggtimer TRS transmitter board first because it s easier to tell if it s working and when you have the receiver completed it will be easy to tell if that one is working too since both boards have LEDs that tell you if they are transmitting receiving data Eggtimer TRS Features Altimeter Features Altimeter rated to 29 500 ft ASL resolution to approx 1 ft Logs data for last 32 flights beeps out or transmits maximum altitude after flight Flight data can be down
38. ely using an Eggfinder LCD receiver Also programmable using USB TTL data cable not included and standard VT100 ANSI text terminal programs compatible with virtually all computers PC Mac Linux Firmware can be updated from a standard PC using the serial cable Power 4 5 30v 2S 7 4V LiPo s 350 mAH minimum recommended Current draw 70 mA average 200 mA at startup Weight about 25 grams size approx 3 9 x 1 2 fits in BT 55 body tube or 38mm coupler Disclaimers Legal Stuff Etc The Eggtimer TRS is meant to be used for hobby and experimental rocketry purposes Although hobby rocketry has an admirable safety record largely due to the efforts of the good people at the National Association of Rocketry NAR and the Tripoli Rocketry Association TRA rocketry can be dangerous if proper safety precautions are not observed This is particularly true with some of the advanced techniques like pyrotechnic parachute deployment People can and have been seriously injured by not following recognized and accepted safety practices We cannot be responsible for your actions We strongly recommend that if you are not a member of either the NAR or the TRA you join one of them join a local rocketry club and pick the brains of experienced members before you try any kind of electronic deployment The safety information included in these instructions is by no means comprehensive or complete and is no substitute for the supervision and advice of
39. ent by 50 feet If you keep tapping the button it will keep incrementing until it reaches the maximum value 1200 feet If you TAP it again you ll see this Main OFF 50 1200 0FF This turns OFF the Main channel which means that it won t fire at all This would be appropriate if you were going to use motor deploy with a single parachute or if you were going to use the Drogue channel to deploy a single parachute near apogee When the Main channel is OFF you will still get a main continuity display but it will ignore the main channel when checking to see if you re ready to fly If you TAP the button from here it will cycle to the minimum value 50 not recommended unless you REALLY know what you re doing and subsequent taps will increment by 50 When you see the value you want PRESS the button for at least 1 second you will hear a beep to confirm your selection then you ll see the next screen Save Options 19 Saving Your Flight Settings and Starting a Flight Once you ve displayed and or changed your settings you can do several things e Discard whatever you ve changed and start a flight with the old settings e Save the new settings and start a flight this is probably what you re most likely to do e Save the new settings and halt the TRS this is what you d do at home the night before e Go back to the Main Menu without saving Note that you cannot save the settings and go back to the
40. ent channel can be tested at a time and the igniter will be fired for the amount of time that you set on the programming screen This includes the 0 continuous setting so make sure that you set it up properly ahead of time To test the Main deployment channel enter the monitor mode by holding the Button down while turning on the Eggtimer TRS You will hear a long beep and you will see a MON gt prompt on the terminal screen Hit the M key and you will hear a continuous warning beep Press the Button and the Main igniter channel will fire for two seconds 45 To test the Drogue deployment channel enter the monitor mode by holding the Button down while turning on the Eggtimer TRS You will hear a long beep and you will see a MON gt prompt on the terminal screen Hit the B key and you will hear a continuous warning beep Press the Button and the Drogue igniter channel will fire for two seconds Afterwards the Eggtimer TRS will go into Reset Mode i e the buzzer will beep slowly and continuously Turn off the deployment power then the Eggtimer TRS power 46 Appendix E Specifications Pressure Sensor Type Bosch BMP 180 accuracy rated to approx 9000 m 29 500 ft Accuracy Approx 1m 3 ft throughout rated pressure range Precision Approx 1 2 m 1 5 ft throughout rated pressure range GPS Type Maestro Wireless A2235H SiRF IV Rate 1 sample sec RF Type Hope RF HM TRP 915 Power 100 mW 20 dBi M
41. es the increment value by hitting the lt key The Esc key usually in the upper left corner of your keyboard exits the screen and saves the flight settings you will hear a long beep that confirms the save and then the Eggtimer will halt both lights will blink continuously The key allows you to download saved flight data more on that later Finally there are a few hidden keys for special functions such as erasing all the flight memory and setting the flight settings to defaults these are covered in the Appendix Note that if you do not hit ANY keys the Eggtimer TRS assumes that you don t have a PC connected and you are ready to start a flight The beep beep that tells you that you are in programming mode lasts for 30 seconds then the Eggtimer begins the flight sequence For this reason if you ARE programming it you should hit Enter a few times to let it know that you have a terminal connection once you do it will terminate the flight sequence and save your settings and halt after you are done programming Note When you first get your Eggtimer TRS the flight memory is NOT initialized Please see Appendix A for instructions on how to clear the flight memory by performing a Master Reset You will need to do this before you can program or fly the Eggtimer TRS or unpredictable results may follow fag ee Field Descriptions A Main Altitude lt 50 1200 by 50 0 OFF gt This setting controls the Main deployment channe
42. format e Close the capture buffer in your terminal program and save it to your computer as a CSV file Buzzer beeps slowly and continuously to let you know that it s done and Halted Flight Status Codes from Flight Summary Download 0 Flight Not Started in programming or pre Ready mode 1 Waiting for LDA 2 LDA reached 3 Not used 4 Not used 5 Mach Lockout expired lt 100 ft sec for over 1 second after LDA 6 Nose Over 7 Drogue deployed if selected 8 Main deployed if selected 9 Landing detected 49 Eggtimer TRS amp Eggfinder LCD Menus MN S44 c c R BR 5 5 O O B B mi mi ga go ge ge me a 2 h ro w Of oO tartup Sequence Eggfinder RX LCD Displays for 5 secs Version 1 09d Status 915 0 Displays for 10 secs GPS D Alt F 6 4V waiting for Sync Looks for Eggtimer TRS up to 30 secs Eggtimer TRS 4N Displays version and Device Name MY EGGTIMER TRS e At this point the two are in sync TAP the button to continue Menus TAP the button to cycle between the menus e Hold the button for 1 second to select the menu Main Menu Check Status Main Menu i Dsp Chg Settings Main Menu Display Flights Main Menu Deploy Test 50 Check Status Menu Main Menu Check Status e HOLD button for 1 second and release to select Status 8 1V DRO OFF MAIN ON e TAP button to exit NOTE If either deployment channel is enabled but there is no cont
43. initiation nowadays use relatively low current well under 1A all fire the guaranteed minimum current requirement for firing Quest Q2G2 s will fire at under 200 mA Typically a very small LiPo is more than adequate for deployment power a 200 mAH battery will easily light any igniter up to about 2A and depending on the battery might be able to source up to 8A Since igniters fire for only a short time and typically will burn open after firing that current may only be drawn for a few tenths of a second You generally CAN use a 9V battery for the deployment side assuming that it will put out enough current for your igniter It will work fine with a Q2G2 IF AND ONLY IF you are using Quest Q2G2 igniters or other low current igniters you can get away with using a single battery for both the computer and deployment side We ve done that many times it works fine if you make sure that your battery is large enough to handle a possible short We recommend that your LiPo battery has enough current capacity to handle 10x the all fire draw of the igniter For example if you are using a J Tek ematch with a 1A all fire rating your battery must be able to handle 10A of current continuously To tell if your battery can handle that look at the C rating of the battery and multiply the capacity by the C rating The C rating tells you how much current the battery can put out continuously the higher the rating the more current the battery can s
44. inuity you will get a beep alert and the channel will flash until you have fixed the problem You CANNOT continue a flight if both deployment channels are not consistent with the state of the channel selection Display Change Settings Menu Main Menu Dsp Chg Settings e HOLD button for 1 second and release to select Drogue Drogue Nose Over Nose Over e Hold button for 1 sec to edit Drogue e TAP button to go to Backup next item Drogue 0FF e TAP button to go to next value e HOLD button for 1 sec to select Main OFF 50 1200 2500 e TAP button to go to next value e HOLD button for 1 sec to select V Main OFF 50 1200 500 51 Save Options Save Options FLY w o Saving ll e TAP button to go e TAP button to to go next value to next item e Hold button for 1 sec e Hold button for 1 sec to select to change Save Options Save and FLY Save Options Save and HALT Save Options Return wo Save Display Flights Main Menu HOLD button for 1 sec to select Display Flights E i Flt 0 28 e Flight Display Summary A 7128 V 864 e Most recent flight 0 memory location 28 2 Al e Altitude 7128 Velocity 864 fps TAP button to get summary for next flight HOLD button for 1 sec to get Flight Milestones see below HOLD button for 7 secs to exit to Main Menu Vv Flight Milestone display o EE e TAP for next value
45. ion of the software please download the latest version from the Eggtimer Rocketry web site www eggtimerrocketry com Also if you have not done so already you will probably want to install an external push button on your Eggfinder LCD receiver rather than using the internal push button You can find instructions for doing that at the end of the Eggfinder LCD Assembly and User s Guide on the Eggtimer Rocketry web site www eggtimerrocketry com Pairing the Eggtimer TRS and Eggfinder LCD When you turn on your Eggtimer TRS it sends out a beacon that tells the Eggfinder LCD receiver Here I Am If you have just turned on your Eggfinder LCD receiver and let it go through the banner 5 seconds and local status display 10 seconds you will see a screen that says Waiting for Sync The Eggfinder LCD receiver listens for the beacon signal from an Eggtimer TRS on the same frequency and ID code If it gets one it pairs with the Eggtimer TRS acknowledging the beacon and going into terminal mode The Eggfinder LCD receiver then displays the software version and Device Name of your transmitter so you know that it s YOUR Eggtimer TRS and not somebody else s The Eggtimer TRS and Eggfinder LCD remain in terminal mode until you either tell it to start a flight or go into Halt mode If the Eggtimer TRS doesn t get a response back from an Egegfinder LCD receiver it assumes that none is present and it goes on to the cable
46. iver this is easy There may be local regulations that prohibit pyro testing where you 39 may be living check with your local fire marshal if you aren t sure If you can t test in your backyard check with your local club to see where you can test they may have an area set aside during launches for such testing 4 Batteries can be heavy especially 9v transistor batteries For best flight performance use the lightest batteries that you can get by with 3 7v single cell Li Po batteries work great for deployment with low current igniters like a Quest Q2G2 but you need to charge them properly and solder 24 gauge tinned pigtails to the battery leads since most of them are very fine and can easily break under flight stress After you solder the pigtails fold the pigtails over and wrap the battery with a couple of wraps of electrical tape to strain relieve the delicate battery leads You can also find these batteries with various kinds of connectors pre mounted you can obtain the matching connector for them with a pigtail and solder it to the board Be sure to put a switch in line with the positive usually RED side of the deployment connector 5 Batteries are a lot cheaper than motors and rockets so if there is any doubt whatsoever about the capacity of your ignition battery replace it When in doubt TEST THEM FIRST before you try to fly them and replace them if they read under 80 of their rated voltage A lot of people
47. l This channel is typically used to deploy the large main parachute at a pre programmed altitude after apogee When set to 0 the channel is turned off and will not fire The altitude and elapsed time of Main deployment are recorded in the Flight Summary memory for downloading Zeroes in these fields means that the Main channel wasn t enabled and therefore didn t fire B Drogue lt 0 Off 1 Drogue 2 Backup gt This setting controls the Channel B deployment channel When set to 0 the channel is turned off When set to 1 the deployment channel turns on at nose over 1 second after apogee If set to 2 it works the same as 1 except that the channel turns on TWO seconds after apogee rather that ONE second after apogee at nose over This allows you to configure an Eggtimer TRS in your rocket to be a backup unit so that a second drogue charge can be fired slightly later than the primary for redundancy In a backup configuration you d also configure the main channel to fire about 100 200 below the primary depending on the altitude that you had the primary set to OAs Programming the Frequency ID Code and Device Name All Eggtimer TRS units are shipped on 915 MHz with an ID Code of zero Using the USB data cable you can change the center frequency and ID code allowing up to 72 Eggtimer TRS units to be running simultaneously In addition you an also name your device so that when you pair your
48. l of the values press the ESC key The values will be saved and you will hear the slow beep beep that indicates that the Eggtimer TRS is halted 25 Flying Your Eggtimer TRS Once you ve programmed your Eggtimer TRS you are ready for a flight In general a generic flight prep procedure for a multiple deployment rocket looks something like this assuming that you re using switches for deployment battery power and also for Reset if you aren t using an LCD receiver If You HAVE an Eggfinder LCD receiver At Your Prep Table Check ALL flight batteries with a DVM and replace recharge as necessary Double check your Flight Settings screen to make sure that all values are correct Confirm that any deployment power switches are OFF Hook up any deployment charges with the computer and deployment batteries disconnected Connect the Eggtimer TRS power battery this will start the pairing sequence Turn on your Egegfinder LCD receiver Wait for the units to pair up leave it at the Main Menu Wait for the 1S light to come on and or a verified fix from the Eggfinder LCD receiver e DO NOT disconnect the Eggtimer TRS battery or you will lose your fix Close up the AV bay and get your rocket ready At the RSO Table Prove to the RSO that the deployment channel s are disabled along with showing them that your rocket is flightworthy of course At the Pad e Put your rocket on the rod rail e Turn on the deployment power e Dou
49. loaded to a computer using USB interface cable included to CSV format for use with virtually any spreadsheet graphing or statistical analysis software package Reports Elapsed Flight Time Altitude Time Raw Velocity Time and filtered Altitude and Velocity Time Flight memory is non volatile so all settings and flight data are retained with the battery disconnected and interrupted flights can still produce a data graph up to the point of failure or impact Fully configurable Main deployment altitude amp Drogue at nose over delayed for use as a backup Supports igniters with a voltage rating of up to 2A i e MJD Quest Q2G2 Uses optoisolators and bipolar driver transistors for total isolation of computer and ignition power and immunity from false ESD or RF triggering and brownout protection Uses separate battery not included for external deployment device providing total immunity from deployment brownouts Can also be used with a single 2S LiPo battery 350 mah 20C min recommended GPS Tracking Features Range approx 10 000 with included wire antenna double that with external antennas Sends real time altitude deployment channel status and GPS coordinate information to an Eggfinder receiver Allows you to track your rocket in flight and walk right up to it afterwards 9 Frequencies and 8 ID Codes up to 72 Eggtimer TRS units can be flown simultaneously Other Features Can be programmed and armed remot
50. lows Cable TRS Black Ground GND White TX RX Green RX TX Plug the USB end into a USB port on your computer Launch your terminal emulator program configure the serial port for 9600 baud and connect to the serial port Power up your Eggtimer TRS you will hear 45 seconds of slow beep beeps as it looks for an Eggfinder LCD receiver Since it s not going to find one it will start beeping faster for another 30 seconds while that is happening you will see this screen When you do hit the Enter key a few times this will let the Eggtimer TRS know that you have a terminal connected and you re not ready to start a flight Note Be sure to hit Enter within 30 seconds of the fast beeps or it will go into flight mode and you ll have to reset it again to get to the programming screen 22 Eggtimer TRS 1 4N Flight Settings MY EGGTIMER T 23 50 P 97804 00 A 1 Drogue lt 0 OFF 1 Nose Over 2 Backup gt A 975 39 B 700 Main Altitude lt 100 2000 by 50 O OFF gt Main 1 Drogue 1 Batt 7 74 900 Frequency Ctrl1 F to Change 0 ID Code Options Letter to Change ESC to Save Options are selected by hitting the letter in front of the value then using the and keys to toggle the values up and down by the increment value for example 50 for the LDA setting 1 for most other settings If the numeric value can be above 10 you can step up by 10 times the increment value by hitting the gt key Similarly you can step down by 10 tim
51. n case the flight was aborted the flight status code more on that later and the total elapsed time of the flight RELEE The flight status is updated by the Eggtimer TRS as the flight progresses and saved into the flight memory In the event that for some reason something goes wrong you can use this value to help you figure it out The status codes are 0 Flight Not Started in programming or pre Ready mode 1 Waiting for LDA 2 LDA reached 3 Not Used 4 Not Used 5 Mach Lockout expired lt 100 ft sec for over 1 second after LDA 6 Nose Over 7 Drogue if selected 8 Main deployed if selected 9 Landing detected Most of the time after a successful flight this code will be a 9 If the rocket gets stuck in a tree for example and the landing altitude is never reached lt 30 ft for at least 5 seconds this will end up being the last previous flight phase for example if it was a multiple deployment flight the last status code will be 8 Main Deployed if there was no deployment selected it will be a 6 Nose Over As you can see from this data the rocket got to 4525 feet had a maximum velocity of 667 feet sec The actual LDA was 203 ft at 700ms into the flight it was set to 200 ft Nose Over and Drogue fired at 4447 ft at 18 secs and the Main fired at 489 ft at 94 secs To download the detail data press the button again you will see something like this T Alt Veloc FAIt Fveloc LDA
52. ned for educational and experimental purposes the Eggtimer TRS is considered by the FCC to be generally exempt from authorization requirements Nonethless we have made a good faith attempt to comply with all technical regulations and you should too by building it exactly as per the instructions and by using only the antenna on the transmitter module that we recommend in the instructions or a suitable replacement as outlined in the Appendix Because the Eggtimer TRS runs on an unlicensed band there is no protection against interference from other sources basically you get what you get We ve done substantial testing and are confident that your Eggtimer TRS is unlikely to be significantly affected by outside radio sources but there s no guarantee If your Eggtimer TRS causes interference in a residential setting or with licensed radio systems such as TV or ham radio you must stop using it until you correct the problem This is extremely unlikely given the small amount of power and the tightness of the transmitter s output and in particular the distance from any population that HPR rockets must be flown Nevertheless you need to be aware of this and be willing to abide by the rules These are the same rules that govern other non licensed transmitters such as cordless phones WiFi and Bluetooth devices and garage door openers Important Links FCC Part 15 governing unlicensed intentional emitters http www ecfr
53. ng the data in every memory location This function is primarily used by the Eggtimer Rocketry technical support staff to debug problems that you may encounter but you can also use it to save all of the flight data prior to a Master Reset if you choose To dump the memory hold the Button down while the power is off or the Eggtimer is in reset mode and continue to hold it down as you turn on the Eggtimer or release the reset You will hear a long beep acknowledging the Monitor mode and you will see a MON gt prompt on the screen If you hit the 0 zero key the last flight s memory will be dumped to the serial port if you hit the A or a key ALL flight memory will be dumped If you press the E button the processor s internal EEPROM is dumped Hold the Button down and release it to start the dump The memory dump format is Page No Page Address Memory Address High Byte Low Byte Integer Value Page No Page Number 0 31 Page Address Address within page 0 2047 Memory Address Address within memory 0 65534 by two s High Byte Byte value of first byte Low Byte Byte value of second byte Integer value Value of integer two s complement if negative Note Memory dumps can take awhile especially the A dump Bie ee Appendix B Deployment Channel Testing You must perform a Master Reset before you can perform deployment channel testing see the Eggtimer Assembly Manual for de
54. ng when in fact it is actually ascending at a rather rapid speed If this were not taken into account the flight computer might deploy parachutes at near mach speed which would undoubtedly break something and ruin your day not to mention what an object falling from the sky at these speeds could do To prevent this from happening the Eggtimer TRS uses a predictive mechanism to hold off deployments until it s safely out of the mach danger zone All deployments are inhibited on startup Real time altitude readings are run through a filter which smoothes the noise from the pressure readings The smoothed readings produce a much gentler velocity profile which allows it to be used to obtain reasonably accurate velocity samples After the LDA has been reached when the velocity drops below 100 ft sec for at least 1 second presumably near apogee deployments are enabled Apogee and Nose Over Assuming that your rocket is moving more or less straight up it will continue to slow down during the coast phase until it gets as high as it s going to go If the rocket was going absolutely straight up the velocity at this point would be zero it would simply start falling to the ground In reality this almost never happens because you usually angle the rod rail at a slight angle so that the rocket takes off away from the flight line This results in the velocity disparity that we ve previously mentioned The rocket usually has some forward
55. o secure it properly If you re familiar with egg lofting you know that you can t just throw an egg in the payload bay and expect it to come back unharmed The Eggtimer TRS is no exception like an egg it needs to be properly protected from the forces of flight The easiest way to do this is to build a sled for it a piece of 1 8 plywood or basswood that can simply slide into the payload bay If properly done a sled can be easily removable for post flight downloading Better yet is to build a payload bay out of couplers that fits into the rocket between the booster and the main parachute sections there are some excellent references for constructing payload sections in the Appendix If you have a L2 size rocket it will probably come with a payload bay If you re lucky it might come with the sled too but if it doesn t you ll probably need to make one 1 8 plywood or 1 16 G10 G12 fiberglass works well The minimum size sled that will work with an Eggtimer TRS is 7 long if you are using the wire antenna If you are going to use an external antenna that takes about 3 off of that but you re going to need an RP SMA extension and an antenna We recommend however that you make the sled as long as the payload bay will allow if you have a 6 payload bay for example your sled should be the entire 6 in length You do not want the sled moving around in the payload bay during flight Mount the Eggtimer with at le
56. odulation FSK Digital Frequency 909 926 750 as used in the Eggtimer TRS Processor Type Atmel ATMega328P Speed 16 MHz Memory Type I2C Serial EEPROM Size 64NB 512 Kb Deployment Voltage 3v 60v Current 8A max 60 W Isolation gt 3000V opto isolator Duration 2 seconds Size Approx 3 9 L x 1 3 W x 5 H Weight Approx 25 grams Power 4 5V 30V min 200 mAH 2S 7 4V LiPo battery 500 mAH or larger recommended Current Draw Startup Approx 200 mA typically lt 2 minutes outdoors Operational Approx 80 mA 47 Eggtimer TRS Quick Reference Release 1 4N Typical Flight Sequence 1 Long Beep Power On 2 Slow Beep Beep for 45 seconds Eggfinder LCD pairing mode 3 Fast Beep Beep for 30 seconds Cabled Programming Mode 4 Pause while baseline samples are taken and self test is executed about 10 seconds 5 Long Beep Self Test passed OR Beep Codes Self Test failed 6 Chirping Ready for Launch Launch 7 Deployment channels fire as programmed during flight 8 At landing lt 30 ft for 5 seconds the apogee is sent continuously over the radio Beep Codes Number of Beeps Problem 1 Battery Low lt 6 5v 2 Altimeter Sensor or Hardware Error 3 GPS error no feed 4 Main error igniter or battery problem 5 Drogue error igniter or battery problem Cable Connections Settings Connections GND Black RX White TX Green Serial Port
57. ou hear depends on the function for example a deployment test sounds a 10 second alarm before it actually pops the igniter so you can get out of the way if you re not already after all that s why you do it remotely The sounds give you an audible confirmation that your function took The Eggtimer TRS Menu Structure After you ve paired your Eggtimer TRS with the Eggfinder LCD receiver you go into the Main Menu The menu structure is very simple there are a few menus that you cycle through by a TAP of the button When you get to the item that you want to select you simply PRESS the button for 1 second or so to select it and the menus for that item will come up If there are further selections menus they work the same way with a few exceptions detailed below When you first enter the Main Menu from pairing you will see this screen Main Menu Check Status This gives you the opportunity to check the status of your Eggtimer TRS unit If you PRESS the button it will be selected If you TAP the button and go onto the next menu you ll see this Main Menu f Dsp Chg Settings 15 This screen is where you would enter your Flight Settings Drogue mode and Main deployment altitude It is also where you go to save your settings and ARM your Eggtimer TRS to start the flight sequence Note that you MUST at least display the flight settings before you are allowed to ARM the unit and start a flight This is done so that you
58. ource If you have a 500 mAH battery rated at 20C that s 10 000 mA or 10A so it would be OK to use that battery with a J Tek match as the sole battery on an Eggtimer TRS General Battery Procedures TEST YOUR BATTERY WITH A DVM BEFORE EVERY FLIGHT If you do not have one buy an inexpensive digital voltmeter and check the battery voltage while the Eggtimer is powered ON before EVERY flight Your battery should be at least 80 of its rated voltage if you are using LiPo batteries you should never let your battery go below 3 1v per cell i e a 2S LiPo should never go below 6 2V If your battery reads below this chances are good that it is damaged and will not retain a charge I Similarly test the deployment batteries as well if you are using electronic deployment Check your igniter vendor s guidelines for recommended voltage and replace the battery if it s close to the minimum value or if the voltage is less than 80 of its rated value whichever is highest For example a Quest Q2G2 igniter will fire with as little as 3 7v a fully charged LiPo cell but if you re using as 9v battery you should replace it if it s under 7 2v 80 of its rated value because its voltage and current sourcing ability drops rapidly as it begins to run down The Eggtimer TRS built in battery tester is designed to be used as a quick check to see if your battery may be getting low It is not a substitute for checking the battery with a DVM it does
59. p safely away from the rocket we recommend at least 30 feet Press the button then cycle through the screens until you get the following screen MAIN MENU DEPLOYMENT TEST Hold the button for at least 1 second then release it You will see DEPLOYMENT TEST DROGUE 44 If you press and release the button you will see DEPLOYMENT TEST MAIN You can cycle through the channels by tapping the button Select whichever channel you wish to test by holding the button for at least 2 seconds You will see MAIN TEST HOLD TO TEST Hold the button down for at least 7 SECONDS you will hear a long tone for 10 seconds then the channel will fire Afterwards you will see TEST COMPLETE EGGTIMER RESET Approach the rocket turn off the deployment power then turn off the Eggtimer TRS Testing with the USB Cable You can also perform a deployment test on your igniter channels with the USB cable by using the Monitor mode This allows you to make sure that the battery and the igniter that you are going to be using for deployment and or airstarts are compatible before actually flying them SAFETY WARNING ALWAYS TEST IGNITERS OUTDOORS WITH A SUITABLE DISTANCE BETWEEN YOU AND THE IGNITER AT LEAST 5 FEET AND NEVER TEST USING THE CABLE WITH A PYROTECHNIC LOAD If the igniter has a lot of pyrogen we strongly recommend that you put it in a tin can or other reasonably fire safe container when you test it Note that only one deploym
60. received fix data If the number of seconds exceeds 99 it will be replaced by The bottom line shows you e Longitude in the units that you chose when you programmed your LCD display e Barometric AGL Above Ground Level altitude from the flight computer This updates in real time as your rocket is in flight it lets you know how high your rocket went and how high it is when it s coming down That helps you know where to look for it although if it went very far you re going to be using the GPS coordinates to find it anyway Also note that the baro altitude changes to the apogee when the rocket lands If the Eggtimer TRS fails a self test you will hear a slow beep that counts out the error code instead of the Ready for Flight tone You will also see an error display on your LCD receiver SELF TEST ERROR CODE n This means that the Egetimer TRS has aborted the flight sequence due to a hardware problem AND YOU SHOULD NOT LAUNCH Deactivate the Eggtimer TRS disconnect the batteries disconnect the motor s igniter and correct the error before attempting the flight again Note that if you have the Eggfinder LCD display paired with your Eggtimer TRS it will not allow you to arm the unit if there is an error The beep codes are 28 Number of Problem Beeps 1 Battery Low Error lt 6 6v 2 Altimeter Sensor or Hardware Error 3 GPS Error no feed 4 Channel A Main error igni
61. tails IMPORTANT The output channels are designed to be used with some kind of resistive load i e an igniter a Christmas Tree light bulb etc NEVER CONNECT A SIMPLE PIECE OF WIRE ACROSS THE DEPLOYMENT TERMINALS TO PERFORM A DEPLOYMENT TEST If you do and your battery is capable of sourcing more than 8A of current i e a LiPo battery you may damage the Eggtimer s output transistors Testing with the Eggfinder LCD Receiver One nice thing about have an Eggfinder LCD receiver is that you can remotely test the deployment channels you don t need to be close to the rocket when you do it This allows you to do a full deployment test including your pyrotechnic charge safely away from the rocket SAFETY WARNING ALWAYS TEST IGNITERS OUTDOORS WITH A SUITABLE DISTANCE BETWEEN YOU AND THE IGNITER AT LEAST 5 FEET If YOU ARE TESTING WITH A PYROTECHNIC LOAD WE RECOMMEND AT LEAST 10 FEET OF DISTANCE BETWEEN YOU AND THE ROCKET AND NEVER STAND IMMEDIATELY IN FRONT OR BEHIND THE ROCKET To perform a deployment test prepare the igniter and charge and the battery Make sure that the deployment power and the Eggtimer TRS power are turned off Mount your rocket on a suitable fixture so that it won t move as the nose cone parachute and protector are ejected by the deployment charge Turn on the Eggtimer TRS and immediately turn on your Eggfinder LCD receiver to pair it up When you get the pairing screen turn on the deployment power then ste
62. ter servo battery 5 Channel B Drogue Airstart error igniter servo battery Important The full self test routine is executed when a flight is started after you hold the button for 7 seconds at the Status screen if you have an LCD receiver or when the programming timouts have expired In the event that it passes self test and a condition arises after it has passed it will NOT notify you of this fact In particular if you turn off the deployment power after the Eggtimer TRS has gone into the Ready for Flight mode the Eggtimer TRS will continue to report that it is Ready However the deployment channel status WILL be displayed on the Eggfinder LCD display so if this should happen then you ll be able to tell hopefully before the LCO presses the button OK we re ready so press the button already In the Air Once your rocket is launched altitude samples are taken at 20 samples per second These samples are saved into a special rotating pool of memory until the LDA altitude is reached at 200 then they begin to be saved into the regular memory When your rocket reaches LDA the velocity profile data also begins to be computed Velocity readings are computed based on the difference in altitude between successive samples and the elapsed time between the samples In a perfect world this would give you a precise and 100 accurate velocity reading The reality is somewhat different however There are several things that
63. that the channel is set to fire about 1 second after apogee This pretty much guarantees that the rocket is just starting come down If you want to change the value PRESS the button for at least 1 second you ll see this Drogue Nose Over The indicates that you can edit the value by tapping the button to change the value The values that you can select are Drogue Backup This delays the Drogue until 2 seconds after apogee which is what you would want to do if you were going to use your TPS as the backup deployment controller in a redundant controller project 18 Drogue OFF This setting turns the Drogue channel off for example if you were going to use motor deploy for the drogue or even the main chute for a single deploy project Note that when the Drogue channel is OFF you will still get a drogue continuity display but it will ignore the drogue channel when checking to see if you re ready to fly To select the displayed value PRESS the button for at least 1 second it will beep to confirm your selection and you ll see the next item that can be changed Main OFF 50 1200 500 This is the Main deployment channel s status The value that s displayed here is 500 feet so the Main channel will fire at 500 feet or so To change it PRESS the button for at least 1 second you ll see the that means you re in CHANGE mode Main OFF 50 1200 250 i If you TAP the button the value will increm
64. through a program like RocSim or Open Rocket to check the stability and predicted flight path of your rocket Google to see if there is a RocSim file for your rocket and or modify it accordingly if you have made changes or have a custom build Yes this IS rocket science 2 Similarly use RocSim Open Rocket to determine the best delay time for the drogue deployment Ideally it should be within one second of predicted apogee when your rocket is moving at a relatively slow speed lt 20 ft sec is ideal If you are going to use the motor s ejection charge to fire the drogue and the motor has a fixed delay time i e one that you cannot drill out to adjust it might be a good idea to do this before you buy your motors so you can purchase them with the correct delay time Of course if you re using the Eggtimer for drogue deployment you don t need to worry about this 3 Prior to flight perform a Ground Test procedure with a test load and your ignition battery We recommend using miniature Christmas Tree lights they work very well for testing with just about any battery that would light up an igniter You should perform at least one Ground Test with the pyrotechnic charge that you are going to be using to be absolutely sure that it will fire with the battery that you choose and that it s strong enough to kick out your parachute This obviously should be done OUTDOORS in a well ventilated area If you have an Eggfinder LCD rece
65. ts are The number in brackets is the memory location in this case 28 The A value is your altitude in feet 7 128 the V value is your maximum velocity in feet per second 864 fps If you TAP the button it will cycle to the next oldest flight until you display all 32 flights If you PRESS the button for at least 1 second you ll get another menu that cycles through the flight statistics for that flight more on that later If you HOLD the button for at least 7 seconds it will exit the Display Flights screen and take you back to the Main Menu After the last flight if you TAP the button you ll see Display Flights t EX1 If you select this item by pressing the button for at least 1 second you will be returned to the Main Menu Displaying Flight Milestones The summary screen for each flight is nice if you want a very quick look at the apogee and velocity of the flight but there s more information available To select a flight to display more detailed information PRESS the button for at least 1 second when the flight that you want to look at is displayed You ll see this screen Re ee Flt 0 28 Apogee 7128 To cycle through the screens simply TAP the button each tap will take you to the next screen FIt 0 28 T Apogee 12 4 This is the time to apogee for that flight FIt 0 28 Max Veloc 864 This the the maximum velocity the same as on the summary display FIt 0 28 T Maxv 2 3
66. ts should be about 12 square inches about 1 8 square inch We recommend that you use three ports equally spaced around the diameter of the tube so each port would be about 1 24 square inch or about 1 4 in diameter You need these ports to be at least four body tube diameters from the tip of the nose cone to prevent possible pressure build ups during high speed flight particularly during mach transition but this is usually not an issue with most multiple deployment rocket configurations because the payload bay is typically located behind the main parachute bay where the pressure buildup is more gradual A quick formula for the diameter of the holes assuming that you are using three is 1 Length of Payload Bay in inches 2 Diameter of body tube in inches 3 Square of 2 4 Multiply 1 and 3 5 Divide by 1500 6 Take the square root This is the diameter of the holes you need For example a small 5 payload bay 1 5 inches in diameter inside of a BT 60 coupler 1 Length of Payload Bay in inches 5 2 Diameter of body tube 1 5 3 Square of 2 2 25 4 1 4 Multiply 1 and 3 11 25 5 Divide by 1500 0075 6 Take the square root 0866 We ll multiply this by 32 to get the size of the drill in 1 32nds it s 2 77 32 so we should be fine with a 3 32 drill bit Make sure that you use a good sharp drill bit you do not want any burrs on the outside of the tube disturbing the airflo
67. tures in this menu to keep you from accidentally starting a deployment test it s pretty much impossible for it to happen accidentally To select the Deployment Test PRESS the button for one second or so If you TAP the button from here there are no more menus so it goes back to the first menu the Check Status menu 16 The Check Status Menu The first menu that you will see when you start up is the Check Status menu This shows you several things about your Eggtimer TRS unit e Battery voltage e Drogue channel continuity e Main channel continuity To select the Display Status menu PRESS the button from the Main Menu screen when you see this screen Main Menu Check Status e PRESS button for 1 second and release to select Status 8 1V DRO OFF MAIN ON If either deployment channel is enabled but there is no continuity you will get a beep alert and the channel will flash until you have fixed the problem You CANNOT continue a flight if either deployment channel is not consistent with the state of the channel selection You will also get a hard stop if the battery voltage is below 6 6V the low battery threshold for a 2S LiPo If the battery voltage is below 6 6V you will see LO BATT on the display There are actually two places where you may see this screen the first one is when you select it from the Main Menu and the second one is right before you arm the TRS to start a flight This gives you two opport
68. u do not need to use the Reset pads if you re using one The Reset terminals are also used to update the firmware on the Eggtimer see the instructions on the Eggtimer web site www eggtimerrocketry com for details Note When you first get your Eggtimer TRS the flight memory is NOT initialized Please see Appendix A for instructions on how to clear the flight memory by performing a Master Reset You will need to do this before you can program or fly the Eggtimer TRS or unpredictable results may follow A Note on Wiring The Eggtimer TRS is designed to have the wires directly soldered to the board This allows you to choose whatever method of terminating the connections you want barrier strips solder directly to the switches etc We ve found that simply wire wrapping the igniters to a tinned pigtail wire soldered to the board works very well for smaller rockets By soldering the pigtails to the board rather than having screw terminal blocks you eliminate the possibility that the wire may work loose from terminal blocks in flight We recommend using 22 26 gauge wire for wiring to the Eggtimer board we like to use the 24 gauge stranded wire that s found in Cat 5 network cables It s cheap easy to find and just the right size It s also twisted together in nice solid striped pairs so it s easy to tell the 9 ce 66 from the wire You can also use solid wire but solid wire is harder to work with and has
69. unities to fix a deployment problem or charge replace your battery before you start a flight The Eggtimer TRS will NOT allow to you to arm the unit to start a flight if one of the deployment channels is not ready or if the battery s voltage is too low This is to prevent you from getting a nasty surprise when your drogue channel doesn t fire and your main does or even worse when neither channel fires 17 Display Change Settings Menu One of the nice things about having the Eggfinder LCD receiver is that it makes it really easy to change your flight settings you don t need to break out the cable and your laptop or even open up the AV bay which can be a pain it the butt for most rockets Once you ve reviewed or changed your settings you can arm the unit to start a flight reset the unit and put it on hold or simply go back to the menus To display or change the flight settings PRESS the button when you see this menu Main Menu Dsp Chg Settings This menu starts out in display only mode you simply TAP the button to go through the items in the menu to review them When you see the item that you want to change you PRESS the button for at least 1 second to select it you will see a in front of the value to indicate that it is in CHANGE mode rather than DISPLAY mode The first setting that you can display change is the Drogue setting Drogue Nose Over This shows you that it s in Nose Over mode which means
70. up to an M sized 200 pound beast We ve seen deployments fail with the top end flight computers and with the low cost units even with redundancy The reality is that most deployment failures are not the fault of the electronics it s usually something mechanical like a bad connection a nose cone that s too tight etc Having your blood sweat and tears free fall from a few thousand feet and bury itself in six feet of dirt is going to ruin your whole day We STRONGLY recommend that you use a checklist every flight so that you don t forget anything We have some on our website under the Downloads section at www eggtimerrocketry com downloads or you can create your own the main thing is that you NEED to use one There are also plenty of other resources online Google is great for finding them We also recommend that you get a copy of the book Modern High Power Rocketry it s full of good information too and subscribing to a forum like The Rocket Forum www rocketryforum com is a really good idea too The Eggtimer TRS Flight Sequence At the Pad As you know by now when you first turn on the Eggtimer TRS you get a long I m on beep followed by 45 seconds of slow beep beeps to indicate that you re in pairing mode then 30 seconds of faster beep beeps for cabled programming mode When you re at the pad and the programming beeps stop or you ve started a flight from the Save Options screen that s when the fun begins
71. usually at least one electronically inclined member who can be bribed with a beverage or two to give you a hand Engineering types love a challenge especially it it s easy for them but hard for you Eggtimer Rocketry warrants that when properly assembled the Eggtimer TRS will perform substantially according to the published documentation This means that we spent a lot of time trying to ensure that it s going to work the way that we say it does and we try to fix things that don t quite work right in a reasonable time Nevertheless we can not and do not warrant that the Eggtimer TRS is perfect and will meet every rocketry purpose for the simple reason that we can t test every possible rocket motor environmental combination It is the buyer s responsibility to determine the suitability of the Eggtimer TRS for their particular purpose If you have a problem with this please contact us and we will be happy to send you a prepaid return label for your unbuilt Eggtimer TRS kit and we will refund your purchase price Meet the Eggtimer TRS The Eggtimer TRS is a barometric altimeter based flight computer with two deployment channels and an integrated GPS RF tracker It can record up to 32 flights of varying length It can deploy two parachutes a drogue chute that deploys near apogee to slow the rocket down from high altitudes and a larger main chute that brings the rocket to a safe landing While this is happening the Eggtimer TRS sends out
72. velocity at apogee hopefully it s relatively small so your parachute deployment happens at a low velocity and won t cause any mechanical problems like a broken shock cord or a zippered tube It also means that you really don t know that you ve reached apogee until after you ve been there since if you have a significant forward component it may still go up a little bit Accordingly the Eggtimer TRS fires the drogue parachute at Nose Over which we define as one second past apogee highest recorded altitude If the rocket is still going up chances are that its altitude is going to keep increasing before a one second interval elapses so you re unlikely to get a false apogee detection If the rocket hasn t gained any more altitude after one second then you must be starting on your way down so the Eggtimer TRS fires the drogue at that point for 2 seconds Assuming that the mechanical portion of the drogue mechanism is working properly your drogue chute will pop out and your rocket will start slowing down If you should run out of flight memory during an actual flight drogue and or main chute deployments WILL occur These events are not dependent on recording the flight samples they are only dependent on time altitude and therefore are completely independent of the recording process The recorded deployment altitude and time ARE dependent on the recording process however so you may not get an accurate deployment altitude time in your
73. w You may want to sand the area around the holes with some 400 extra fine sandpaper to smooth out any burrs or flash and possibly harden it slightly with some thin CA glue too Appendix A Special Functions There are some special functions that are accessed from the settings screen that are not on the menu In general you will probably not need to use these functions very often if at all but you need to be aware of them in case you do Master Reset A master reset completely clears all flight memory and resets the flight settings to the defaults The default settings are Main Altitude 500 Drogue Enable 1 Nose Over Device Name MY EGGTIMER TRS To perform a Master Reset hold the Ctrl and Y keys down together at the Flight Settings screen you will then see this screen Eggtimer TRS 1 4N Master Reset KKK WARNING RRR DO YOU REALLY WANT TO CLEAR ALL FLIGHT MEMORY Press BUTTON for 10 seconds to Reset To perform the reset you need to hold the Button on the Eggtimer TRS down for at least 10 seconds When you do you will hear a long confirmation tone then you will see a progress screen as the memory pages are reset Leave the Eggtimer alone until the process is complete When the reset is complete you will see Master Reset Completed you need to reset or power down the Eggtimer TRS before you can use it Memory Dump 42 The Memory Dump writes comma separated variable CSV data to the serial port containi

Eggtimer TRS Flight Computer User`s Manual

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