User Manual
Contents
1. 15 2 Calculating Angle of Tilt From Acceleration ccccssesseeseeeeeeeees 16 3 FreeTall MOLE CUON ossi E 16 4 Limitations of These MethodsS cccccscceeeeeeeeeeeeeeneeeeseeseneseeseneees 16 Appendix C Algorithm References c cccscceeceeeeeneeneseneeneeeeseneeeeseneees 18 1 Converting From Acceleration to Tilt a nannnnnannnnnnnnnnnnnnnnnnnnnnnnnnnnn 18 2 Controlling a Rolling Ball by Tilting eee eeeeeeeeeeeeeeeeeeeeees 18 3 Detecting Freefall csa 20 7 Jolt Detectio 9 eee ee een an an ae een See ee See ae ee een ee nee Soe ener See eee a eee eee 21 EVALUATION BOARDIKIT IMPORTANT NOTICE KIONIX provides the enclosed product s under the following conditions This evaluation board kit is intended for ENGINEERING DEVELOPMENT DEMONSTRATION OR EVALUATION PURPOSES ONLY and is not considered by KIONIX to be a finished end product fit for general consumer use Persons handling the product s must have electronics training and observe good engineering practice standards As such the goods being provided are not intended to be complete in terms of required design marketing and or manufacturing related protective considerations including product safety and environmental measures typically found in end products that incorporate such semiconductor components or circuit boards This evaluation board kit does not fall within the scope of the European Union directives regarding e2. Start Read accelerations X Y and Z Y Calculate total acceleration ACC A sqrt x 2 y 2 z 2 Y Compare ACC to LAST ACC Difference greater than JOLT THRESHOLD _ 4 No y Sf A jolt has occurred y Store ACC in LAST_ACC JOLT THRESHOLD 1 g Amount by which the overall acceleration reading must change between readings to be considered a Le Ole ACCX ACCY ACCZ sensor allreadings TAST ACC squire mOOL TACK Z CY 2A ae ACOA 2 while running ACCX ACCY ACCZ sensor allreadings ACG SGUacS TOO ACO 2 hs ACC Zor CGA e522 JOUR sabsOluce value ACe LAST ACG Lf JOLT gt JOLT THRESHOLD then fi A Folt has ocurred end if LAST ACE ACC end while Page 21
3. 1onix Wireless Demo Board Kit User s Manual September 21 2007 Table of Contents I Zigbee IEEE 802 15 14 wireless standard cccscceeeeseseeeeeeeeeeeeesenees 1 Technical OVERVIOW sisisctecancsscciasanscsccuasnscaasuradcactateaneciuanisictedaerecavesssscaesaaeina 1 Product Specifications ccceccceeeeeeeseceeeeeeceneeneeeeeeneceesensoneneesensoneseesoneneeseneoes 1 ll Driver Installation amp Configuration ccccccsceeseseeeeeeeeeeseeeseeeseneseneseeeseees 2 II Kionix Demo Software ccccecccecceeeeeeseneeneeeeeeesoneeeesenscnseeesensonesensonseneseneens 8 ls 2AGCCCICLALION Dala arnan a a a S 9 Ze OSCIOSCOPE oana a 9 S Data IbOGGCR sean a 9 A SD Bali a 10 S GUSO nrrnysar a a N a ane ann oon eens 10 6 Freefall ainn anions enya eee mee 10 ks PAC OS AUD rascsictassescccea ac Scaswstvwscnwaneicdan see deawaa ducnwnneneceneanwoutwen Winans 10 IV Sengital Serial MSM Analyzer V4 1 00 0 0 ce ceeecceeeeeeeeeeeeeeeneeeeeeeeseeesenenenes 11 Vi APPENdICE S avedreceetitartiee neti eee eens 12 Appendix A Programmer s Manual ccceseeeeeeeeeeeeneeneensenseneeneeneees 12 g Al cd I a Renee eee nee Pe errr cen rer Ste rere err err ec r rer nt rere rere errr errr rr rar 12 2 COMMUNICATION savikaina 14 Appendix B Basic Concepts of MOotion cccesecseeeeeeeeeeeeeeeseneeneseneees 15 1 Calculating Velocity and Distance From Acceleration
4. To locate driver files and complete the Installation click Mert What do you want the wizard to do Search for a suitable driver for my device recommended Display a list of the known drivers for this device so that can choose a specific driver Back Cancel Found New Hardware Wizard Locate Driver Files Where do you want Windows to search for driver files Search for driver files for the following hardware device oD USB lt gt Serial The wizard searches for suitable drivers in its diver database on your computer and in any of the following optional search locations that you specify To start the search click Next IF you are searching on a floppy disk or CO ROM drive Insert the floppy dick of CD before clicking Next Optional search locations CD ROM drives M Specify a location Microsoft Windows Update e Select the folder that contains the FTDI drivers Found Sew Hardware Wizard E x Insert the manufacturer s installation disk into the drive OK selected and then click OF Copy manuacturer s files from OriverSUSB to Sernal Driver in2000 AS90521 5 4 a i Browse Page 3 Found New Hardware Wizard Driver Files Search Results The wizard has finished searching for driwer files for your hardware device The wizard found a driwer for the following device op USB lt gt Serial Windows found a driwer for this device To install the driver Windo
5. H System devices A Universal Serial Bus controllers BUSH 7 m Computer H E Disk drives i m Display adapters Hd 8 DYDICD ROM drives i E Floppy disk controllers i Floppy disk drives fy IDE ATASATAPT controllers ae Keyboards rst Mice and other pointing devices a Monitors gt Multifunction adapters H H Network adapters ai r Forts COM amp LPT on Communications Port COMI oY ECP Printer Port LPT1 TEK PCI Sl seal Parallel F Port LPT2 a SCST dR RAID aa Sound video and game controllers System devices Universal Serial Bus controllers Page 6 e Select Port Settings USB Serial Port COM Properties Use this device enable 7 USE Serial Port COM3 Properties o Bit per Second 38400 o Data bits 8 o Parity None o Stop bits 1 o Flow control None e Click OK Page lll Kionix Demo Software Configure Run the configure program to set the correct parameters for the demo board The configuration program shown in the figure below will allow you to configure communication with the device Configure 1 Interface The method used to communicate with the ee device Currently the method is Streaming os ee ae 2 Device The driver specific to the Kionix part being used peyice Sengitatw ireless SengitalWireless is the correct device for the wireless eae demo board Address COMS 3 Serial Port This selects the port to which the de
6. ba bileVelociey lt PRECTION tien ball velocityX 0 else 1f ball velocityX gt 0 then Dall velocity ball velocityx FRICTION else ball velocityX ball velocityX FRICTION end if end if i aosoluce Value ba li Velociueyy lt PRECTION then ball velocityY 0 else 1f ball velocityY gt 0 then ball velocuiyyYy DallevelocIity FRICTION else pall velocity ballsvelocityy FRICTION end if end if Add average velocity to position ball positionXx ball positionX average belleveloecrieyx OQLDVELX ball positionY ball positionY average ball velocityY OLDVELY end while Page 19 3 Detecting Free fall COo Sat Read accelerations X Y andZ lt Calculate total acceleration A A sqrt x 2 y 2 z 2 Compare A to the freefall threshold Depending on the application 0 3g to 0 5g is usually a reliable threshold y bs P 7 K i E IsA PEN han threshold va No Z Yes y y Freefall Not Freefall FREEFALL 0 3 g Threshold under which the object is considered to be in free fall IN FREEFALL false Stores whether or not the device is A faking while running ACCX ACCY ACCZ sensor allreadings TOTAL AC Sova Se 2000 ACO S 2 PACC O12 r ACCA Zz LE TOTAL ACC lt FREEFALL Chen DN EREE EALCD Cric else TA REE Pls TaLe end if end while Page 20 4 Jolt Detection
7. placed on a piece of machinery to issue an alert if the pattern of movement changes significantly indicating the possible need for maintenance Kionix Accelerometer Demo 3 Data Logger The data logger takes a constant stream of readings a HF from the device and graphs them in real time to the screen Sampling is done by setting the time you wish to sample the rate at which you wish to sample and pressing Go Note that the sample rate you specify is the target sample rate If you specify a very high number the program may read less samples than you expect If you wish to save the data you collected press Save to write the Sample Time 3 Seconds data to a CSV comma separated values file You a Go Save Mark can then use Excel MatLab etc to analyze and graph the data Page 9 4 3D Ball The 3D Ball demo is a simple demonstration of accelerometer based controls in video games By tilting the device the user is able to roll the ball around the board and roll over the red target Additionally a strong bump applied to the z axis of the device will cause the ball to bounce into the air A game development team could use this unique control scheme to add a new level of playability to games like the classic Marble Madness by Atari Games or to create an entirely new game of their own Other games which this could be used with include motorcycle racing snowboarding skateboarding and jet fighter game
8. present if the object is rotating can throw off free fall detection by causing the overall acceleration of the object to be significantly higher than zero even when the object is actually in free fall This effect can be reduced by putting the device in a heavy casing positioning the accelerometer as close as possible to the device s center of mass and allowing a range of values to represent free fall 0 0 to 0 5g is usually a safe range to use Free fall Time When an Object is Thrown An object is in free fall as soon as no forces except for gravity are acting on it That means that if you throw the device upward it will be in free fall even when it is falling upward Similarly being thrown downward will shorten the time the object is in free fall before it hits the ground Either of these events will throw off the equation presented in Free fall Detection above which assumes that the object was released into free fall with a velocity of zero This limitation is not an issue for applications such as hard drive protection as they are only concerned with the fact that the object has been dropped but can adversely affect applications in which the distance the object fell is important In these cases it may be better to use an accelerometer with a higher range and implement impact detection instead of using a low range accelerometer for detecting free fall Page 1 Appendix C Algorithm References 1 Converting From Acceleration
9. will be read as zero Having a dead zone can filter out noise but at the cost of losing real readings if they are very small The default of O is perfect for the demonstration programs When you are finished adjusting the settings press Save to save and exit the program Page 8 1 Acceleration Data The Acceleration_Data demo shows the current readings of the 5 x device in the most raw form as is possible For those interested Kionis Serial Demo Board 29 tri axis in pure data a device could be attached to a piece of memory to Ace a00 store a running log of all readings The data could be retrieved acee MOOG later for analysis The actual collection and processing of acer oag accelerometer data does not require very much processor acz posz o power and the sample rate of the device is very high so an accelerometer can be added to almost any application while creating minimal overhead Figure 2 Acceleration _Data Status 2 Oscilloscope The Virtual Oscilloscope demo graphs data in a simple visual format to give the viewer a general idea of the pattens present in the motion of the device By recognizing these patterns such a device could become integral in several kinds of applications A free fall detector could be used to fee protect important data by spinning down a hard drive before it hits the ground A jolt detector could create a record of package mishandling during shipping A vibration detector could be
10. e Page 13 These options are accepted by sensors which can return AccxX AccY and AccZ respectively They are the amount by which the reading is adjusted to account for slight offsets in the zero position of the sensor These are usually set during a calibration process like the one in the configure pl example script DeadZonex DeadZoneY DeadZonezZ These options are accepted by sensors which can return AccX AccY and AccZ respectively They specify a minimum absolute value above which each reading must be If the reading is within the dead zone for the axis it is simply returned as zero These are usually set to filter out noise when the device is level 2 Communication For those who wish to communicate with the device in their own program or programming language of choice this section details how communication with the demo board takes place Commands The following commands can be issued to the demo board once communication has been established Code Description Return X Get X axis acceleration X 2 byte integer Y Get Y axis acceleration Y 2 byte integer Z Get Z axis acceleration Z 2 byte integer A Return all three axes XYZ three 2 byte integers T Echo a T useful for checking board status T 1 byte character 0x54 Return Values The value returned for an axis reading is stored as a 2 byte integer in little endian least significant byte first order That is the value can b
11. e calculated with the following equation Reading FirstByte SecondByte x 256 The resulting value represents a number on an arbitrary scale set by the analog to digital converter taking the reading To convert this value to millivolts the following equation is used Millivolts Reading 1000 1241 2121 Finally to change the reading in millivolts into the acceleration in g s subtract the Og offset or center usually Vdd 2 or 1650mv for a 3 3V part Then divide by the sensitivity rating of the part in mv g This demo board uses a device with a sensitivity of 660 mv g thus Acceleration Millivolts Center 660 The resulting number is the acceleration value returned by the sensor in g s Page 14 Appendix B Basic Concepts of Motion The concepts discussed in this section are widely available and are a part of any Physics course but they have been reproduced here both as a refresher and as a quick reference useful to anyone working with accelerometer data There is also a discussion of the limitations of these methods when used to determine the position or tilt of a device using a tri axis accelerometer 1 Calculating Velocity and Distance From Acceleration Given an acceleration a and a period of time t it is possible to calculate the change in velocity during the relevant time period If the original velocity is also available the velocity at the end of the time period and the change in position over the ti
12. fications Supports point to multipoint communication Physical Environmental Physical size L W H 52 22 6mm Operating temperature 40 C to 85 C Storage temperature 40 C to 85 C Humidity 10 90 Small 52x22x6 mm form factor Power requirements 500 pA Idle 30 mA Transmit mode 37 mA Receive mode e The demo board is powered by a CR2450 3 volt battery e The sensor runs at a bandwidth of 50Hz e The demonstration programs read samples at about 50 samples second e S1 is a reset button for the module S2 is a user configurable button Button 1 S3 is another user configurable button Button 2 ll Driver Installation amp Configuration e The drivers for the transceiver are available from Future Technology Devices International FTDI as a free download http www ftdichip com Drivers VCP htm e Unzip the FTDI drivers into a new folder e Connect the Transceiver to the USB port on the computer e Windows will try to configure the device Found New Hardware USB lt gt Serial Installing Page 2 Found New Hardware Wizard Install Hardware Device Drivers A device driver is a software program that enables a hardware device to work with an operating system This wizard wall complete the installation for this device vi USB lt gt Serial 4 device driver is a sothware program that makes a hardware device work Windows needs driver files for your new device
13. he saber to turn off Moving the demo board will again activate the light saber Figure 8 Virtual Lightsaber IV Sengital Serial MSM Analyzer V4 1 Sengital Limited developed the wireless sensor module using KXPA4 for Kionix Inc The Sengital software and manual have been included as another example of accelerometer analysis software Use Serial MSM_Analyzer V4 1 2 7V exe to start the Sengital program The user manual details the connection procedure Page 11 V Appendices Appendix A Programmer s Manual 1 Perl API The Perl API for the Kionix demo board provides an easy object oriented interface for a Perl programmer to access acceleration data It is invoked in much the same way as any other Perl module and returns an object which can be used to interact with the sensor Usage Create a new Sensor object from scratch USS DensoOr My SSenseOr Semsor new Sseriak Fr wAcesZors POPE A gt CO Me os SSensor gt open or warn Failed to open sensor Create a Sensor object from an existing configuration file use sensor my SSensor Sensor gt newFromConfig default ini SSensor gt open or warn Failed to open sensor Sensor Methods The following methods are universal to all Sensor objects Sensor gt new SInterface SDevice Options Create a new object based on the interface driver Interface and the device driver SDriver The Options hash will be used to override default opti
14. hese Methods While these equations are effective for many applications there are several limitations and gotchas that one has to watch for when using the data returned by the accelerometer Noise In Acceleration gt Velocity gt Distance Calculations All measurements contain a small amount of background noise Unfortunately in an Page 16 acceleration reading noise can disrupt the apparent velocity of the device This difference will become more apparent over time as the phantom velocity pushes the distance measurements farther and farther from reality This change will be relatively slow however due to the low noise nature of the device The difference can also be made less visible by taking an average of several readings instead of acting on each reading as it arrives A dead zone can also be implemented risking the possible loss of the actual readings if they are very small Differentiating Between Tilt and Motion While the ability to measure either motion or tilt is very useful it comes with the unfortunate disadvantage of not being able to easily differentiate between the two The Z axis of this device may make this distinction possible on the x and y axes by watching the effect of the acceleration in question on the z axis and the acquired data could be applied to future demos Of course associated equations will also be made available Rotation and Center of Mass in Free fall Detection Centripetal acceleration
15. lectromagnetic compatibility restricted substances ROHS recycling WEEE FCC CE or UL and therefore may not meet the technical requirements of these directives or other related directives Kionix warrants that the evaluation board kit sold will upon shipment be free of defects in materials and workmanship under normal and proper usage This warranty shall expire 30 days from date of shipment Kionix will repair or replace at Kionix s discretion any defective goods upon prompt written notice from the Customer within the warranty period Such repair or replacement shall constitute fulfillment of all liabilities of Kionix with respect to warranty and shall constitute Customer s exclusive remedy for defective goods The user assumes all responsibility and liability for proper and safe handling of the goods Further the user indemnifies KIONIX from all claims arising from the handling or use of the goods Due to the open construction of the product it is the user s responsibility to take any and all appropriate precautions with regard to electrostatic discharge IT IS HEREBY EXPRESSLY AGREED THAT KIONIX MAKES AND CUSTOMER RECEIVES NO OTHER WARRANTY EXPRESS OR IMPLIED THAT ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED AND THAT KIONIX SHALL HAVE NO LIABILITY UNDER ANY CIRCUMSTANCES FOR CONSEQUENTIAL INCIDENTAL OR EXEMPLARY DAMAGES ARISING IN ANY WAY FROM THE MISUSE OF ITS PRODUCTS KIONIX as
16. me period can be calculated Lastly if the original position is available the position at the end of the time period can be calculated This can be done according to the steps below Calculating Change in Velocity Given a the acceleration applied on the axis Given t the time period for which the acceleration was applied Av at Results in Av the change in velocity during the time period Calculating Final Velocity Given Av from the previous equation Given Vo the velocity at the start of the time period v v tAv Results in v the velocity at the end of the time period Calculating Change in Distance Given Vo v and t from previous equations 2 Results in Ad the change in distance during the time period Calculating Final Distance Given Ad from the previous equation Given do the distance at the start of the time period d do Ad Results in d the distance at the end of the time period Conclusion At the end of these equations we have both the final velocity v and the final distance d This information can be used to determine the same values in the next time period resulting in a continuous flow of acceleration velocity and distance data Page 15 2 Calculating Angle of Tilt From Acceleration The acceleration data can also be used to find how far the device is tilted This can be done because the Earth is always pulling on the device with 1g of acceleration If the device is put on a flat surface a
17. nd is completely still all of that acceleration is on the Z axis The acceleration on the X and Y axes will be zero If the object is put on its side whichever axis is pointed toward the earth will read 1g Getting the angle from the readings on an axis can be done two different ways The simplest way although it is not very exact is to multiply the acceleration on the axis by 90 x For a much more exact value take the inverse sine of the acceleration For more information see Kionix Application Note ANOOS5 on Tilt Sensing http www kionix com sensors application notes html 3 Free fall Detection A tri axis accelerometer can be used to detect when an object is in free fall The first step is to calculate the overall magnitude of the acceleration being applied to the object This is done with the Pythagorean Theorem a yx y z 2 If the object is in free fall the value will be very close to zero Depending on the rotation of the object however it may be a somewhat higher number see Limitations of These Methods below for details The distance the object fell can be calculated by using gravity g 9 8 m s as acceleration a in the equation for calculating distance d from acceleration a and time t datar 2 Note that this calculation will produce the wrong number if the object has been thrown upward or downward Again see Limitations of These Methods below for more details 4 Limitations of T
18. ons if it is included Sensor gt newFromConfig SFile Override Create a new object reading configuration options from File The Override hash can be used to override options read from the configuration file oSensor load Config S File Load configuration options from SFile and apply them to Sensor esensor Sconrigure key sValue Sets a configuration option for the object Valid options are detailed in Configuration Options below SSensor gt open Opens the sensor and prepares it for reading Returns true or false depending on if the open was successful SSensor gt close Closes the sensor Returns true of false depending on if the close was successful SSensor gt canMeasure Page 12 SSensor gt canMeasure SReading SSensor gt canMeasure Readings When called with no parameters canMeasure returns a list of all the readings a sensor can return When called with one parameter canMeasure returns a true or false indicating if that reading can be returned When called with multiple parameters canMeasure returns a true or false value indicating if all of the readings can be returned SSensor gt status Returns the status of the device 1 indicating a ready status and 0 indicating a bad Status If there is no way to determine the status of the device this command returns undef SSensor gt SReading Return the desired reading as indicated by SReading Reading can be any of the measuremen
19. radio PHY and medium access control MAC communication layers defined by the IEEE 802 15 4 standard Above this ZigBee defines mesh star and cluster tree network topologies with data security features and interoperable application profiles The ZigBee specification provides a cost effective standards based wireless networking solution that supports low data rates low power consumption security and reliability ZigBee technology combines interoperable hardware and software to help make the design process easy and efficient ZigBee technology is suited to a variety of markets including sensor networks Product Specifications Kionix USB Transceiver Features Specifications Freescale MC13191 chipset 16 RF channels Seven general purpose input output GPIO signals Frequency 2 4GHz to 2 4835GHz DSSS Modulation Indoor Range 20 40 meters 13 I O pins for MCU connection Outdoor Range 80 100 meters Four internal timer comparators available to reduce Supports 250 kbps O QPSK in 5 0 Mhz channels MCU resource requirements and full soread spectrum encode and decode Programmable frequency clock output for use by RX sensitivity of 91 dBm typical at 1 0 packet MCU error rate Supports MC9SO08GT16 Vdd 3 3V Supports point to point communication Three power down modes 0 2 pA Off current 2 3 UA Typical Hibernate current 35 pA Typical Doze current no CLKO Page 1 Features Speci
20. s Figure 5 3D Ball 5 Cursor The mouse cursor is a simple demonstration of the idea of a tilt mouse After opening the program the mouse cursor can be moved by tipping the device To end this program press CTRL C 6 Freefall The Free fall Detector demo is an example of the free fall Freefall Palais detection algorithm described in Appendix B It registers when it Time s Distance ft has been in free fall for half a foot then reports how far it fell when 43 Ara it reaches the bottom of its fall Logging can be temporarily OSR en paused with the Stop button or the log can be saved toa CSV 7 1e 140 comma separated values file with the Save button For more details on the algorithm see Free fall Detection in Appendix B E Stop Save Quit Figure 6 Freefall 7 Spaceship This Perl program demonstrates how an accelerometer can be used as a game controller The tilt action is translated to control the movements of a virtual spaceship Avoid the asteroids If you crash into an asteroid the game will end and need to be closed and restarted to begin again Figure 7 Spaceship Page 10 8 Virtual Light Saber The virtual light saber shows the unique values available from a tri axis accelerometer The light saber is activated by picking up or moving the demo board As you move the demo board the light saber will mimic your moves Ten seconds of inactivity will cause t
21. sumes no liability for applications assistance customer product design software performance or infringement of patents or services described herein No license is granted under any patent right or other intellectual property right of KIONIX covering or relating to any machine process or combination in which such KIONIX products or services might be or are used FCC Warning This evaluation board kit is intended for ENGINEERING DEVELOPMENT DEMONSTRATION OR EVALUATION PURPOSES ONLY and is not considered by KIONIX to be a finished end product fit for general consumer use It generates uses and can radiate radio frequency energy and has not been tested for compliance with the limits of computing devices pursuant to part 15 of FCC rules which are designed to provide reasonable protection against radio frequency interference Operation of this equipment in other environments may cause interference with radio communications in which case the user at his own expense will be required to take whatever measures may be required to correct this interference Kionix Inc 36 Thornwood Drive Ithaca NY 14850 www kionix com Page 3 I Zigbee IEEE 802 15 14 wireless standard Technical Overview ZigBee is a new global standard for wireless connectivity focusing on standardizing and enabling the interoperability of consumer electronic products as well as building automation and industrial control and monitoring ZigBee is built on the robust
22. to Tilt roll arctan pitch p arctan X JY Z7 Y V X74Z7 2 Controlling a Rolling Ball by Tilting Initialize Ball with position and velocity at zero Read accelerations X and Y A Add acceleration X to velocity X gt Add acceleration Y to velocity Y Y Slow velocity X by FRICTION The best value for FRICTION depends on the application gt Slow velocity Y by FRICTION The best value for FRICTION depends on the application Y Add the average of velocity X to position X The average of velocity X is the average of the X velocity at the beginning of this time period and the X velocity at the end of this time period Add the average of velocity Y to position Y The average of velocity Y is the average of the Y velocity at the beginning of this time period and the Y velocity at the end of this time period Y Update Screen Page 18 ball positions ball positionyY ball velocityxX ball velocityyY OOOO while running ACCX ACCY ACCZ sensor allreadings OLDVELX ball velocityX OLDVELY ball velocityyY Add acceleration to velocity ball velocityx ballsveloecityx ACCX ball velocityY Pall velocity ACCY For a better feel the following implements friction The best value for FRICTION depends on jf the apo lication LE absolute Value
23. ts returned by Sensor gt canMeasure Foran example see Measurements Available From a TriAxis2g Sensor below Measurements Available From a TriAxis2g Sensor SSensor gt Accx SSensor gt AccyY SSensor gt AccZ Returns acceleration on the X Y or Z axis This value is in g s the acceleration due to the Earth s gravity Thatis 1g 9 8m s For tilt calculations 1g 90 More information on using the values returned by an accelerometer can be found in Appendix B Basic Concepts of Motion SSensor gt Acc Unlike the other readings Acc is a calculated value It is based on AccX AccY and AccZ using the Pythagorean Theorem in three dimensions It is a measurement of the magnitude of the acceleration currently being applied to the accelerometer without the direction It is useful for applications such as jolt and free fall detection SSensor gt AccAl1 Returns an array of the X Y and Z accelerations Note that because all three of these are sampled anyway each time any one reading is taken using this method is three times faster than calling AccX AccY and AccZ in succession Configuration Options The following options can be passed to the configure method POPC This option is accepted by any object using the Serial interface driver It specifies which COM port the sensor is plugged into AGTUS TX AGSUSEY Ad uUStZ Specifically the calculation used to get overall acceleration is a TED ay
24. vice is connected Press Scan to limit the list to ports that can l actually be accessed A label to the right of the button will _Test _ 4ccess appear showing how many ports were found to be Performance available Then select the port to which the device is Senay 3 connected from the address pull down above and press agustx ooemse4 Test to check that the device is connected properly If it adusty oomsac is a label will appear to the right of the Test button AdustZ 0 0144997 confirming that the test was a success Dead Zone 0 Dead Zone O 4 Performance These boxes show the adjustments made 5 420nez a to readings received You may enter these manually if you wish but it is easiest to lay the device flat press Calibrate and accept the default settings Cancel Save Sensitivity This is a pull down menu for selecting Figure 1 configure p Calibrate the sensitivity of the demo board Sensitivity is set at the factory You must select the correct g level for your board or the demos will not function properly The default sensitivity is 2g Adjust X Y Z These are the amounts by which each reading on the relevant axis is adjusted in g s before it is returned This is to account for any slight variations in center the device might have Dead Zone X Y Z This is the minimum absolute value a reading must reach before it is registered If it is below this value it
25. ws found click Next z c documents and settings jolearn desktop usb to sernal divervusb to sernal diverwain2Q00 50521 54 Ftdibus int e Set the correct com port From the Start Settings menu o Open Control Panel o Click on System f Control Panel File Edit View Favorites Tools Help de Gack mp EA Search U4 Folders Ea Las LE x e E Address Contral Panel Accessibility Options E QuickTime E Add Remove Hardware RealPlayer ee Add Remove Programs Regional Options l Administrative Tools Scanners and Cameras ma Adobe Samma Scheduled Tasks Automatic Updates gf Sounds and Multimedia Ai AvantGo Connect ye Speech pi DateTime Li Display os Text Services Fax p Users and Passwords Provides system information and changes environment settii jj Folder Options _A Fonts ee Java H Network and Dial up Connections fat Phone and Modem Options RA Power Options Printers Provides system information and changes environment settings Z Page 4 System Properties e Select Hardware and click Device Manager Page 5 7 m Computer E Disk drives Display adapters Fd 8 DVD CD ROM drives 4 Floppy disk controllers 4 Floppy disk drives H IDE ATA ATAPI controllers ae Keyboards E Mice and other pointing devices ee Monitors H 4 Multifunction adapters H ag Network adapters E Ff Ports COM amp LPT H SCSI and RAID controllers De Sound video and game controllers
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