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design and implementation of manual assembly control system

1. E 16 Figure 2 4 Control box top perti enu ra 17 Fig re 2 5 Control box top ISIS 17 Figure 2 6 Detail on control BOX 17 Figure 2 7 Control box bottom inner View materies pr bo opes En ted EE SR 18 Figure 2 8 Detail on control box bottom Laus coe tet inc 18 Figure 2 9 Sensor box left ote EU UH IR Le dea reet 19 Figure 2 10 Light transmission of the IR glass against wavelength 20 Figure 2 11 Sensor m 20 Figure 2 12 Control POB T 2l Figure 2 13 WAGO 733 series Connector 21 Figure 2 14 Emitter POB rp EE EA 22 Figure 2 15 Reverse Gullwing EBD 22 Figure 2 16 JST SMB11 COnnector 23 gt Figure 2 17 Positioning of emitters and receivers to avoid non matched beam 24 Figure 2 18 Console box front frontal view 2 25 8 Figure 2 19 Console box front with assembled parts 25 8 Figure 2 20 Console box front top view with assembled parts 26 2 Figure 2 21 Console box back 26 E Figure 2 22 Console box back outer view UM uq UMS 26 5 2 23 Console Box 27 E Pipe 2 24
2. Qxogaptsuy Suo Osonsneis Queis quiassy K quiassy Opunog ua33 ag Syuo Suo syuoD 6 L 2 t I P 8 9 0 51 1 5 spe1ouduod v i UI 5 NIVIA 5 S 1 10121250 ozi eniug 8 2 FLOWCHARTS Figure 7 2 SetInRange Y menu menu nOptions menu menu 90 nOptions Firmware Version funcN ASM MENU Start MAIN MENU Variable Initialization lt gt s Y Menu Menu Menu Start Assembly Config Menu 4 U up Y Menu funcN CONFIG_ME NU nOptions 2 Hides config menu nOptions 3 SetInRange 0 END Figure 7 3 Main menu function flowchart FLOWCHARTS Config Menu Initialize Variables CONFIGURATION MENU Men Menu Menu Conf m Menu Menu Conf Conf Between Conf Time Activate Error Boxes Parts Box Box Inside Box Statistics B Back optionC D down FuncN lt MAIN MENU E Enter funcN FuncN elle funcN funcN funcN CONFIG_N_ _ _ CONFIG_TIME
3. DRAWINGS DRAWINGS Bibliography Samuel PE Stephen M 2013 Basic to Advanced Computer Aided Design Using NX 8 5 San Jos Design Visionaries Duncan Mitchell 2013 Learning to fly with Eagle V6 getting started guide Amersfoort Netherlands Wilco Microchip Technology Incorporated 2012 2015 MPLAB 8 C Compiler User s Guide U S A Microchip Technology Incorporated Microchip Technology Incorporated 2006 PIC18F2455 2550 4455 4550 Data Sheet U S A Microchip Technology Incorporated Vishay Electronics 5 feb 2014 TSOP772 TSOP774 IR Receiver Modules for Remote Control Systems Vishay Electronics Vishay Semiconductors 23 Aug 2011 VSMB200X01 2020 01 High Speed Infrared Emitting Diodes Vishay Semiconductors L Hode 2012 Penetration of light into living tissue http www laser nu Japanese Solderless Terminals JST Catalogue Vol 120e
4. vcc vf Imax 3 3 1 15 0 1 21 5 Ohm and then Prlim I 2 R 21 5 0 1 2 0 215 W added V I 1 15 0 1 20 115 W So the power draw for each LED and resistor is 0 330W Two LED will never be active together so it means the power draw of all LED s will be maximum the same as one LED active all the time In case the voltage is 5V VCC 5 1 15V so Rlimit vec vf Imax 5 1 15 0 1 38 5 Ohm and then Prlim I 2 R 38 5 0 1 22 0 385 W added 1 1 15 0 1 20 115 W So the power draw is 2 0 5W The emitters will be switched through transistors which power consumption should be also considered The chosen device is the 2n7002 which an internal on resistance of 5 Ohm Design and implementation of manual assembly control system As before said maximum current through emitters will be 100mA which gives a value for the power consumption of Pzl 2 R 5 0 1 2 0 05 Figure 3 10 Emitters 3 7 RECEIVERS PCB From the beginning the system was thought to be tested with 2 types of sensors so we will get the calculations for both of them Option with phototransistors Taking in consideration the calculations shown in the corresponding section the maximum power consumption will be 25mW per phototransistor what means 200mW total Option with photo receiver The power consumption of this device comes directly extracted
5. 3 10 ut 48 Figure 3 11 Photoreceiver block diagram oit e ttm 50 Figure 5 1 Las r cut acrylgl as eee Re D AREA RA ERE 66 Figure 5 2 FDM printed patti Pn onto 67 Figure 5 3 Injection molding inre tecti eei 67 Piek and place mae Mine utr 68 Figure 7 1 Menu 78 Figure 7 2 Main function flowchart 79 Figure 7 3 Main menu function flowchart ei eR Sd 80 Figure 7 4 Configuration 8l Figure 7 5 Assembly menu flowchart 82 Figure 7 6 Assembly process 83 Figure 7 7 Determine box process flowchart eue entered te tere uei redeant 84 Figure 7 8 Configure number of parts flowchart 85 Figure 7 9 Flowchart of miscellaneous configuration 86 Figure 7 10 Error handler flowchart 87 Figure 7 11 Flowchart of the process to check if all defined boxes are connected 88 Figure 7 12 Flowchart of several used functions ae 89 Figure 7 13 Flowchar
6. Z 27 2 2 4 4 4 7 7 Figure 2 17 Positioning of emitters and receivers to avoid non matched beam Anyways after further experimentation the designed realized that there are secondary beams pointing to the receivers thing that could be used as a feature to improve the detection system if it s properly managed through software 2 4 CONSOLE As mentioned before holds all the electronics to interact with the device the connectors for the boxes but also the power supply and the supply switch Let s show the parts that compose the console and the design limitations The components of the console are Box Front Box Back Box Top Box Bottom Console PCB comprising all the components fixed to it Locker MECHANICAL DESIGN Screen Encoder button power plug power switch buzzer relay 2 4 1 BOX FRONT AND BACK The Box Front and the Box Back are the parts in which all the components with outer access will be attached so in case of the front it will contain holes for the locker the screen the encoder and the button It will also have four holes in the corners to fix it to the top and the bottom The back will contain the holes for the power switch the power plug the connector for four sensor controllers and the chain connectivity which will be described in more detail in the electronic design section It also con
7. Laser cutter service min Mechanical Designer h Electronic Designer PCB development h Embedder software programmer h Electronics technician PCB soldering 10 0 4 16 18 15 0 59 220 50 30 120 175 140 20 3 9 220 50 12 1920 3150 2100 200 7814 7 COSTS 8 2PRODUCTION COSTS TOOL COST PROVIDER ITEM Protomold Protomold Protomold Protomold Protomold Protomold gruenwald gruenwald PART COST Aluminium casting mold CONTROL BOX FRONT Aluminium casting mold CONTROL BOX Aluminium casting mold SENSOR BOX LEFT Aluminium casting mold SENSOR BOX RIGHT Aluminium casting mold CONSOLE BOX TOP Aluminium casting mold CONSOLE BOX BOTTOM Pick and place programming costs all PCB Stencils all PCB QTY UNIT PRICE 7242 45 5146 2 4827 6 4827 6 8116 2 7815 15 300 200 COST 7242 45 5146 2 4827 6 4827 6 8116 2 7815 15 300 200 Design and implementation of manual assembly control system Protomold Protomold Protomold Protomold Protomold Protomold gruenwald gruenwald gruenwald gruenwald seeedstudio seeedstudio seeedstudio TOTAL SET COST Control box front Material ABS Black Control box back Material ABS Black Sensor box left Material ABS Black Control box right Material ABS Black Console box top Material ABS Black Co
8. The designer of this project will use the schematic and the layout editor for the development of the electronic circuitry Besides there are some scripts which allow eagle to use simulation they are quite complicated tools not fully integrated in the software and most of the time the simulations need components to be replaced which makes simulation unworthy The main advantage of the EAGLE software is the existence of free versions for hobbyists and students downloadable directly from CADSOFT ELECTRONIC DESIGN 3 3 PREVIOUS CALCULATIONS Given by the specification there will be a maximum of 4 boxes each of them will have the same power consumption The starting point will be a power supply of maximum 10W to try to design a non excessive consuming device In case is not possible to meet the specification using only 10W the power supply will be resized So a safety margin for the power supply will be used using only the 70 of the rated value which means maximum power consumption of the system 7W 4 boxes with same power draw we assign a maximum power draw per box to 1 W From the calculations related to the beam and the number of sensors needed to properly detect a hand inside the container we will get a total 8 emitters and 8 receivers which power draw was estimated to be a maximum of 0 5W for emitters 100mW for the receivers The power consumption of the PIC is estimated to be 0 15W through the measurement of
9. The sensors which are pointing through the PCB using a reverse Gullwing package quite rarely used so besides the Figure 2 15 Reverse 5 TE Gullwing LED soldering pads of the sensors are on the side seen in figure 2 15 the sensors will be pointing through a hole on the PCB to the sensor receiver PCB MECHANICAL DESIGN Pay attention also to the connector which is the smallest form factor the writer could find to make it fit in such a small space The connector is a JST SMIISB 11 contacts with 1 mm pitch Figure 2 16 JST SMB11 connector Important to note the distance between the sensors which will be always 23 mm for the reasons explained in the section 2 3 6 due to the characteristics of the emitters and receivers 2 3 6 POSITIONING OF THE SENSORS As will be easy to appreciate at the drawings 2 7 and 2 8 where the emitters and the receivers are shown the distance between emitters is always 23 mm same as the distance between receivers so they re pointing to each other The reason to use this distance is to try to avoid the beam of the adjacent emitters over any sensors which is not the one the emitter is pointing Looking at the Datasheet of the VSMB2020 we can find the angle of half sensitivity being 12 which means an effective beam angle of 24 as can be seen in the figure 2 17 Design and implementation of manual assembly control system 768
10. adapter QTY 50 UNIT PRICE 0 8 3 45 3 6 4 1 4 1 0 05 1 9 4 65 4 2 5 9 0 7 0 85 1 7 1 2 COST 0 8 10 35 10 8 12 3 12 3 2 5 1 9 4 65 42 5 9 1 4 4 25 8 5 COSTS ebay farnell ebay ebay microchip segor ebay wago wago wago ebay ebay ebay ebay ebay segor farnell farnell JST farnell farnell Keyes rotary encoder module Buzzer PKM34EW 1101C 1201C Solid state relay module OMRON G3MB Coil relay module PIC18F4550 sample Capacitor 0805 220nF Transistor 2n7002 Connector 733 334 sample Connector 733 336 sample Connector 734 132 sample LED green 0805 LED white 0805 MINI 360 regulator Pin header male 40 contacts SMD 0805 resistor kit DIP switch 8 contacts Power supply VTX 214 010 112 Power supply VTX 214 010 124 Connector JST SM11SB samples IR LED VSMB2000 IR Phototransistor VEMT2000x01 10 100 50 50 10 10 10 10 10 3 19 2 65 1 05 0 05 0 013 0 0204 0 0204 0 12 6 5 0 4 10 1 10 1 0 46 0 66 3 19 2 65 2 1 0 5 1 3 1 02 1 02 1 2 6 5 10 1 10 1 4 0 6 6 Design and implementation of manual assembly control system farnell seeedstudio various WORK fab lab berlin designer designer designer designer TOTAL IR Receiver TSOP77436TR PCB prototypes various 10 set Other various
11. controllers to the central console is something to take in consideration ELECTRONIC DESIGN Due to the limitation given by the connectors used SHR 11V S the wire to be used for the sensor controller connection will be the recommended by the manufacturer of the connectors which is in the range of AWG 32 to AWG 28 The position of the different pins on both PCB s were chosen to be able to crimp the wires with a simple correspondence meaning this that the pin number in the sensor PCB and the control PCB is the same or inverted so the last pin on the receivers correspond to the first pin on the console and vice versa This is an important fact so it will be easier to find already crimped wires following this specification than a random disposal of the pins This will also reduce the manufacturing costs For the case of the wires which connect the console and the controllers the connectors were chosen to be able to replace the wiring with ease so the company which acquires this project can exchange them depending on their needs Right now the designer is using 1 27mm pitch 4 poles ribbon cable Design and implementation of manual assembly control system wv SOFTWARE DESIGN 4 SOFTWARE DESIGN UI9 s s A quiesse enueur Jo pue 4 1 INTRODUCTION There will be two main parts in the software design one regarding to the console and the other on regar
12. MECHANICAL DESIGN 2 3 4 CONTROL PCB Figure 2 12 Control PCB The spots of interest in the Control PCB besides the screwing holes used to fix the PCB to the SENSOR BOX BACK are the connectors The blue ones JST SM11SB to match the connectors needed on the Sensor PCB still those connectors don t contribute with any extra advantage to the PCB in difference with the case of the sensor PCB so it s possible that they will get replaced for other kind of connectors The white connectors are WAGO 733 334 and 733 335 fitting on those the plugs from the same manufactured with the reference 733 104 and 733 105 The main advantage of using this connector is that they are 0 1 Figure 2 13 WAGO 733 series connector Design and implementation of manual assembly control system inch pitch so is really easy to find other connectors which easily fit on them also advantage of being able to exchange easily the wires attached on the 733 104 105 see figure 2 13 2 3 5 SENSOR RECEIVER PCB Those are the PCB s containing the emitters and the receivers themselves the description of such devices is out of the scope of this chapter so it will be explained later when talking about the electronic design Figure 2 14 Emitter PCB Regarding to the mechanical design the interesting aspects of the PCB are those The hollows in the PCB for the fixation with the sensor box the shape
13. the power draw of other similar designs The control PCB also contains a couple of LED s used to check the correct operation of the device consuming 0 01 W almost negligible power draw Also the pull up resistors used for a possible I2C communication have a non relevant power draw Considering an efficiency on the power regulator which supplies the whole control board of a 90 this device is rated with a maximum efficiency of 9590 on its sweet spot This means in the worst case we will be under the maximum assigned power consumption which is IW per box Using 3 3 volts the power draw will be considerably reduced but this could cause problems with the communication with the console so this point should be revisited after the device testing IMPORTANT NOTE Design and implementation of manual assembly control system Those were only rough calculations to have a first impression of power draws needed by the different parts of the system to dimension the power supply and the regulator but the final design may differ 3 4 SENSOR CONTROLLER The sensor controller as its name says will be in charge of controlling the sensors attached to every container besides all parts of the system together can be seen as a whole circuit it will be divided in three different parts regarding to the division in different PCB s that has been done in the system for mechanical reasons to get properly adapted to the cont
14. 29 Keyes encoder module MECHANICAL DESIGN The button is a 1662 0101 switch from MARQUARDT the dimensions of this button are a de facto standard so it s possible to find lots of other buttons with the same dimensions figure 2 30 Both input devices are placed to interact with the console located on the right side taking in consideration most of the population is right handed should be easier to use besides the designer is left Figure 2 30 Button handed power plug and power switch The power switch is a so called rocker switch there are several different models with the same specification but in this case the used one will be the MARQUARDT 1801 1121 Figure 2 31 Rocker switch The power plug is a C7 IEC standard female power plug There are lots of different manufacturers which provide this kind of connector Keeping the switch close to the plug it gets Figure 2 32 C7 IEC power plug clear 15 to switch off the machine on the back side Design and implementation of manual assembly control system Buzzer The used buzzer Figure 2 33 is one of the most common models used by the Arduino community which most probably will be a PKM34EW 1101C 1201C from the manufacturer MURATA This buzzer emits sound when some operations are performed if fixed to the housing will transmit better the vibrations Figure 2 33 Buzzer Relay To connect to other devices relate
15. Cons l OR 27 3 Figure 2 25 Top and bottom sides including PCB and buzzer 28 5 5 Figure 2 26 Console PCB 29 Figure 2 27 Locker 29 S Figure 2 28 1602 LCD Screen 30 5 Figure 2 29 Keyes encoder module ous 30 E 2 30 BUONA ooo eoe o D delete ee ade a ee da otia Le cen 31 tents 3l Figure 2 32 CT TEC power plug EO TED IER et os Ue da uu ERR UR Vrae CUIR o ud 31 Figure 2 33 32 Figure 2 34 Relay un d o Ecoute db 32 Fipure 3 1 Console Schematic ione eeu 37 Figure 2s PIC ISEPAS50 Dre hii ghisa oat eter tt eher ea lae oq Deere ea naids 38 Figure 3 3 PIGTISIA550 features eec di 38 Figure 5 4 s Gontr ller rinde tas afit oeste etg fetal to tela estes doi Ma eee 39 Figure 3 5 217002 characteristics ad ee EU Se ecce 40 3 6 Console citu i pasivo dot 43 Figure 3 7 DIP Switches itio EU tee Reed 45 Figure 3 8 Encoder turning counter clockwise two steps 46 Figure 3 9 Encoder turning clockwise two steps idee eed pne dad ee ane 46
16. LED s was necessary the use of a mobile phone with camera taking the advantage to the fact that most of the camera sensors are sensitive to IR light While testing the controller for the first time the IR LED s weren t working at all After some time looking for the problem they randomly started to work Finding the problem took quite long time during which some other tests were performed until the system started to fail again Finally was found out that the problem was due to a cold solder made in the pins of the connector of the IR LED s PCB 6 3 4 TEST 4 SOME RECEIVERS NOT WORKING The first point to check if the receivers are working properly is to check if they have their outputs high when no infrared modulated light is emitted on them Checking with the multimeter it emerged that 3 of the outputs weren t high After checking the conductivity of some tracks on the PCB was found out that some pins of the sensor weren t in contact with their pads due most probably to a cold solder After re soldering the faulty sensors were tested again giving the right values 6 3 5 TEST 5 IR LED LIMITING RESISTORS HEATING IN EXCESS To check the code of the controller for the first time and to be able to clearly see through the camera the IR LED s were working the LED s were flashing without modulation which means they were always active obligating the LED s and their limiting resistors to dissipate much more power heating up fast
17. and the worker should then repeat the process with the box with the corresponding number shown in the screen Once all parts from all boxes are extracted the process starts again If there s a detection in a box which is not the one shown or there s a try of a simultaneous extraction from several boxes the system will display the error and get locked In case the time assigned to extract the part from the box and assemble it expires or the system is detecting a hand object inside the box for too long the system will behave in the same way as before mentioned Once the system is locked the it will change the state of the relay locking also the other processes in the assembly chain Then the system will keep locked until the supervisor unlocks it using the provided keys for the electric locker Then the worker will be able to start the assembly again Design and implementation of manual assembly control system 4 3 CONTROLLER FIRMWARE The goal of the controller firmware is to generate the proper signal on the emitters to excite the receivers and to capture the value of the receivers so is possible to know if there s any cut on the beam between the emitter and the receiver This is the basic way to find out if there s any interaction inside the boxes This method starts being quite simple but it will be subject to changes to improve its reliability This process should also toggle from time to time the RUN LED em
18. control system 1 PROJECT JUSTIFICATION Design and implementation of manual assembly control system 1 1 BACKGROUND In several times there were errors in the products acquired by customers of company for which this system is being designed Despite those errors are not big failures they result in products that must be replaced with the consequent damage to the image of reliability of the company and the confidence of the customers on it Currently there is not any control system to identify any possible error in the manual assembly process done by the workers Taking in consideration the company for which this project is being built wants to keep the defect ratio under 10 parts per million it s important to keep all the possible sources of error as controlled as possible justifying on this manner the following project 1 2 PROBLEM DEFINITION Due to the lack of a control system on the manual assembly process some distractions made by the assembly workers could give as a result apparently correct assemblies not possible to be detected in the critical quality controls but which can in a short period of time end up in a malfunction giving as a result a problem in the offered services to the final customer 1 3 JUSTIFICATION To avoid the previously mentioned problems and being able to guarantee better quality and reliability to the customer of those assembled products in the present cas
19. cours CONFIG_ CONFIG_ BOXES PARTS INSIDE_BOX SOUND STATISTICS BETWEEN_ BOXES Setin Range Return Figure 7 4 Configuration menu flowchart 8l Design and implementation of manual assembly control system ASSEMBLY MENU Assembly Menu connected CheckBoxes connected functionN lt MAIN MENU Assembly Start Return Figure 7 5 Assembly menu flowchart FLOWCHARTS 83 Initialize variables Yes Activate alarm timer no detected Determine Box yes 4 ext detected error type 3 open Other box right box multiple boxes Exit closed Error type 1 2 Y functionN lt MAIN MENU Restart nd no detected Determine Box yes E AS SEMBLY is l ART Error type 4 NParts 1 lt max nParts Next box gt max 4 lt yes Restart variables Figure 7 6 Assembly process flowchart Design and implementation of manual assembly control system pA ou 594 soxogu gt 0212224 12212 ou So saxogu HNINAYA LAC ou gt p soxogu ou box process flowchart De
20. to their maximum allowed values Cutting off the power prevented the LED s to blow up 6 3 6 TEST 6 DRIVING THE LED S WITH THE TEST BURST As written in the datasheet of the receiver there s a test burst which ensures the sensors will be excited The code to generate such burst was loaded on the microcontroller to drive only one IR LED When measuring the outputs of the receivers all of them were low while the test LED was emitting the burst when the expected result was to get this signal only in the receiver which was coupled with the active IR LED Moreover cutting the beam of the LED with any object doesn t change the output of the receivers Further tests shown there are some objects that can stop the light to excite the receivers but only when in a special angle which directs orthogonally all the reflections of the IR beams and with very opaque objects The result of the experiments exhibits two problems The IR LED s are extremely powerful for the requirements of the IR barrier producing lots of reflections which excite all the receivers not being able to differentiate which IR LED emits the beam being this a possible error focus The human flesh is not as opaque to IR light as it is to visible light what means that even if a hand is blocking the beam between an emitter and a receiver the sensor could miss its detection Drastically reducing the emission power of the LED s could solve the problem so the current
21. DESIGN AND IMPLEMENTATION OF MANUAL ASSEMBLY CONTROL SYSTEM Quesada Navarro Telecommunications technical engineer Specialty in Sound and Image engineering Table of contents SADLER WVU eR 3 TIN 7 1 PROJECT JUSTIFICATION inpet 9 IL BACKGROUND 5 55 405 ia 10 1 2 PROBLEM DEFINITION rV 10 1 3 JUSTIFICATION 10 IS MM SILET 11 1 5 SCOPE AND LIMITATIONS NE 12 12 2 MECHANICAL DESIGN 13 2 1 INTRODUCTION huit RI ER RIAL 14 22 SOFTWARE 15 2 3 SENSOR CONTROLLER 15 ZSICONTROL BOK DNI ME 17 2 3 2 CONTROL BOX BOT TONL etd 18 2 3 3 SENSOR BOX LEFT RIGHT ERE RA 19 2 340 SENSOR GLAS S 20 PASS EO SEN 21 2 3 5 SENSOR RECEIVER POB 22 2 3 6 POSITIONING OF THE SENSORS 23 22 C 24 2 4 1 BOX FERONT AND BACK inni 25 2 4 2 BOX TOP AND BOTTOM eeiam inna 27 DESIGN A
22. ER OF BOXES to ERROR STATISTICS are an intermediate step to get into the actual configuration process used to display the corresponding name Regarding to their functionality they can be grouped all together 4 2 2 6 Configure Number of boxes This option allows the user to change the number of boxes the system will use in a specific assembly each box represents a different part The current system will have capability for up to 4 different parts but it could allow up to 8 boxes with the current console hardware and up to 16 doing minor design modifications Those modifications will be done only under demand Turning right or left will increase or decrease the number of boxes pushing enter will save the current value back will leave the menu without saving The maximum value of boxes will be kept in the range before defined 4 2 2 7 Configure parts per box Through this menu option the user will be able to decide how many equal parts will be used in the assembly extracted from the same box and Down will increase decrease the number of parts in the currently displayed box Enter will move to the next box Once in the last box it will quit automatically Back will quit the configuration menu without saving the currently displayed number of parts 4 2 2 8 Time between boxes inside box Used to determine the timings the assembly workers can stay idle without taking the next part of the assembly The behavior
23. Hz Internal Oscillator Block 8 user selectable frequencies from 31 kHz to 8 MHz User tunable to compensate for frequency drift Secondary Oscillator using Timer 8 32 kHz Dual Oscillator options allow microcontroller and USB module to run at different clock speeds Fail Safe Clock Monitor Allows for safe shutdown if any clock stops Figure 3 2 PIC18F4550 highlights Peripheral Highlights High Current Sink Source 25 mA 25 mA Three External Interrupts Four Timer modules TimerO to Timer3 Up to 2 Capture Compare PWM CCP modules Capture is 16 bit max resolution 5 2 ns Tcv 16 Compare is 16 bit max resolution 83 3 ns Tcv PWM output PWM resolution is 1 to 10 bit Enhanced Capture Compare PWM ECCP module Multiple output modes Selectable polarity Programmable dead time Auto shutdown and auto restart Enhanced USART module LIN bus support Master Synchronous Serial Port MSSP module supporting 3 wire SPI all 4 modes and Master and Slave modes 10 bit up to 13 channel Analog to Digital Converter module A D with Programmable Acquisition Time Dual Analog Comparators with Input Multiplexing Special Microcontroller Features C Compiler Optimized Architecture with optional Extended Instruction Set 100 000 Erase Write Cycle Enhanced Flash Program Memory typical 1 000 000 Erase Write Cycle Data EEPROM Memory typical Flash Data EEPROM Retention 40 years Self Program
24. ND IMPLEMENTATION OF MANUAL ASSEMBLY CONTROL 3 2 43 CONSOLE POB 28 2 4 4 OTHER 5 eet ttt tnt 29 3 ELECTRONIC DESIGN pet 33 34 34 3 3 PREVIOUS CALCULATIONS 35 3 4 SENSOR CONTROLLER 36 3 4 1 CONTROLLER 36 BO CONSOLE LUE 43 NE 46 CODREGEIVERS P 48 3 8 WIRING 50 4 SOFTWARE DESIGN ettet ttt ttt 53 44 INTRODUCTION di rac t fet 54 42 CONSOLE FIRM WARE e b C oce tbc eb 55 421 USER INTERFACE 56 g 4 22 MENU OPTIONS AND CONFIGURATION PARAMETERS ss 8 4 2 3 ASSEMBLY PROCESS AND SYSTEM LOCKING 61 E 4 3 CONTROLLER FIRMWARE ettet ttt 62 5 PROTOTYPE AND PRODUCTION ttt ttt 65 5 1 MECHANICAL PARTS eerte 66 E 5 2 PRINTED CIRCUIT BOARDS Ea acsi ite leiden 68 6 TESTS AND MODIFICATIONS iiti tonic ua cod 6 5 6 1 PROBLEMS ON THE BASIC FUNCTIONALITY ee 70 5 6 1 1 HOT PLUGGING AND 70 5 6 1 2 RESET PROBLEMS WATCHDOG 70 E G13 DONNEDEPORS S 7 e 6 14 IK LED EXCESSIVELY POWERFUL cest 71 6 1 5 E
25. RE DESIGN If after finishing the whole burst the saved variable goes over a predefined threshold it will count as a positive object detection Once there s a positive detection the cable connected to the central console will get high The system will continue sensing for a positive detection while holding the console cable high At the point the sensing gives as a result a negative in the detection the system will wait for a defined time expecting a second negative detection to pull down the console communication pin This pause and double check is a way to debounce the sensor system As can be seen in the figure 7 12 the LED blinks every defined number of detection cycle defined by the variable max in the LED toggle flowchart This means the LED isn t blinking on a fixed timing but depending on the timings of the sensing process Design and implementation of manual assembly control system 5 PRODUCTION Design and implementation of manual assembly control system 5 1 MECHANICAL PARTS To check the proper functionality of the parts as a part of the redesign of a system is important the use of prototypes The prototypes manufactured for this project are done with two different systems laser cut parts and 3D printed parts Laser Cutting The laser cut manufacturing is usually used with B parts which have a flat dimension so they can be produced by cutting them a
26. RROR IN THE PCB LAY OUT 71 6 2 FURTHER MODIFICATIONS un te etit 22 6 2 1 CONNECTING MORE SENSOR BOXES isses een 72 6 2 2 USING PORT TO CONNECT WITH THE CONTROLLERS 72 6 2 3 POSSIBLE WIRELESS COMMUNICATION 72 62 4SPECOMMUNICA THON 73 6 2 5 CHANGE ARM ARCHITECTURE 522 73 0 3 TESTS qe 73 6 3 1 TEST I ENCODER PROBLEMS serie serio nee noh eae dan eu cio 13 632 TEST 2 THE CONSOLE GETS STUCK itr etate RC PER pta 74 6 3 3 TEST 3 IR LED S RANDOMLY NOT WORKING eee 74 6 3 4 TEST 4 SOME RECEIVERS NOT WORKING eee 74 6 3 5 TEST 5 IR LED LIMITING RESISTORS HEATING IN EXCESS 74 6 3 6 TEST 6 DRIVING THE LED S WITH THE TEST BURST 75 6 3 7 TEST 7 DRIVING LED S WITH LOWER CURRENT ene 75 6 3 8 TEST 8 LIGHT SOURCE INTERFERENCES eese 76 de 6 icone QUADRI RU DELI EDAM UIN EUN EEUU 77 MESS M E 93 So DEVELOPMENT COSTS s n fa denn abe qudd 94 8 2 PRODUCTION COSTS RI cH Ie Rt RR RUPEE GE 97 DRAWINGS 353 mm 101 Table of figures Table of figures Figure 2 3 Container with the sensors and controller already assembled 16 Figure 2 CC 16 gru
27. ainer and also thinking in the possibility of replacing some of the sensing modules for others with different characteristics Besides as said there will be three differentiated parts also will be added a possible variation to one of them So the sensor controller will be divided in the following Controller board Containing the control logic the power regulation and a power stage for the LED driving Emitter board Containing the IR LED s used as emitters Receiver board Having two different alternatives First case using phototransistors second case using IR receivers the justification for this alternatives will be explained in the corresponding section 3 4 1 CONTROLLER BOARD Let us get started having a look to the final schematic design to point out the used components ELECTRONIC DESIGN EL Figure 3 1 Console Schematic As can be seen in the figure 3 1 The circuit contains The microcontroller at the center A connector to the in circuit programmer on the center top The connector to the IR LED s the current limiting resistors for the LED s and the transistors needed to drive them to a higher current than the pins of the microcontroller can supply on the left side Another connector for the receivers with pull down resistors for each sensor on the left side The power and the run LED s with its current
28. and the connection process itself generates large voltage and current spikes which generate resets on the microcontroller of the console To avoid this kind of behavior and enabling a real hot plug system the use of NTC s in series to the power pin which goes to the different boxes will make the current to be small when the boxes are connected and while the heat on the NTC s increase their resistance will go down letting the current rise slowly until a stationary state in which the power draw of the NCT will be negligible 6 1 2 RESET PROBLEMS WATCHDOG There are lots of different reasons why a microcontroller can get stuck As explained in the previous section big variations in the power draw generating current spikes is one of them But also for example a close device generating EMI electromagnetic irradiation or a bad code could paralyze the microcontroller To avoid that there s a special device on the microcontrollers called watchdog which can generate an automatic reset on the microcontroller on a regular time basis when it s timer is not software reset This is a fantastic method to get a reliable device but it requires to structure the code in some way which allows to perform all the tasks before the watchdog timer overflow Unfortunately the code wasn t properly structured for it and the designer doesn t have the time to modify code before first release but will probably be modified in case there s a seco
29. ast job SIEMENS NX 15 a powerful parametric mechanical design software which allows to easily reshape the different parts involved in a mechanical design through a complex system of relations between design features and the use of constraints over them This software is also capable to manage high complexity assemblies and the relation between them through constraints 2 3 SENSOR CONTROLLER The sensor controller is at the same time divided in several subparts Control box top Control box bottom Sensor box right Sensor box left Sensor glasses right and left Control PCB which will be only briefly described regarding to the mechanical characteristics due to the fact that this part belongs also to the electronic design section emitters PCB receivers PCB These two last parts will also have a brief description for the same reasons mentioned for the case of the Control PCB Before the beginning of the description of the different parts let s have a look to the figure 2 and 2 2 showing the container Design and implementation of manual assembly control system Figure 2 2 Figure 2 1 And a second picture containing the whole assembly Figure 2 3 Container with the sensors and controller already assembled MECHANICAL DESIGN 2 3 1 CONTROL BOX TOP The Control Box Top part will be the one which covers the electronic control circuitry it will also have as can be seen in figu
30. at adapts naturally the shapes of the container Optimize the form factor Allocate the connectors to the console in a way that allow easy access avoiding to disturb the normal workflow Create a design which is easy to assemble and disassemble But also other needs as creating a mechanically robust design which protects the sensors and to design on such way that the parts are easily manufacturable in long scale Moving now to the console which is holding the human computer interface the requirements are quite different taking in consideration it doesn t need to get adapted to an already existing external component The priority on this case is the ease to use meaning that the following Locate the input devices in a way that is easy to access and use Locate the output devices in a way they are easy to read to provide the required feedback Give easy access to the connectivity to the controllers as to the system output Contain the electrical net connectors and switches to switch on and off the system Same as housing the power supply and the electronic circuitry related with the console and as in the case of the sensor housings the manufacturability will be taken in consideration MECHANICAL DESIGN 2 2 SOFTWARE The software to be used for the design of the mechanical components of the system will be SIEMENS NX due to the experience of the designer with the previously mentioned software during his l
31. bedded on the PCB to easily detect the proper function of the microcontroller To try to get a better detection there are some characteristics to remark to clarify the some of the characteristics of its function The receivers work with 36MHz light what means there s a need to generate at the LED s signal with the same frequency to excite them This will be defined as a burst Given the information on the datasheet it s not possible to emit continuously over the sensors or they will lose their sensitivity what means there will be a pause between bursts When there isn t any strange object like a hand inside the container the receivers get the light from the IR diodes but in a multiplexed way what means each of the detectors receives a burst pauses and then the next detector repeats the same process in a continuous cycle So during the time the IR LED is emitting directly to the receiver in the case there s nothing cutting the beam its output level will be LOW and HIGH during the rest of the time to perform a full multiplexed cycle So the moment to detect if there s a cut on the beam meaning this a strange body inside the container like a hand for example is while generating the burst This process is also documented in the figure 7 12 Every time the IR LED gets high to generate the burst the output of its corresponding detector will be checked and a variable will be increased if the receptor is low SOFTWA
32. ct but if the time would be available this modification can represent the biggest performance improvement of the system not functionality improvement which will be the wireless communication system 6 3 TESTS 6 3 1 TEST 1 ENCODER PROBLEMS The encoder used for the very first development differs from the currently used The driver for the encoder was developed for the former encoder type so there s a need of modifying the encoder driver to use it with the new model After trying to approach the problem in several different ways gets clear that the modifications to be done need to be much bigger than expected declining the designer to make those modifications before the deadline This modifications could be done when re writing the console software in a possible next revision Besides not totally correct the console still useable with some modifications on the encoder driver Design and implementation of manual assembly control system 6 3 2 TEST 2 THE CONSOLE GETS STUCK The console gets stuck randomly from time to time to solve this there will be a plan to readapt the code to use the watchdog in the next revision of the software currently not implemented making the system less reliable 6 3 3 TEST 3 IR LED S RANDOMLY NOT WORKING Using IR light for the development of the sensors means it s not possible to check the proper function of the LED s just looking at them for all the checks done to the IR
33. d with the assembly process This device doesn t have any kind of fixation because it could easily change the shape and dimensions of the module and at the moment of the beginning of the manufacturing from the PCB s this component wasn t clearly determined As can be seen in figure 2 34 this is only a simplified indicative Figure 2 34 Relay model UI9 s s A quiesse enueur Jo pue 3 ELECTRONIC DESIGN 3 1 INTRODUCTION The electronic design part consists mostly in the design of the PCB and the choice of the right electronic components for meeting the required characteristics given in the specification and given by the relations of the components between themselves besides this text is structured in a very linear way this far away from a real design stage which is mostly iterative in which the designer conveniently changes some to get adapted to other Also is the same with the relation between the mechanical design and the electronics design So this is only the result of this iterative process 3 2 SOFTWARE The software used for the electronic design during this project will be EAGLE EAGLE is flexible expandable and scriptable electronic design application with schematic capture editor PCB layout editor auto router and CAM and BOM tools Besides is not a very intuitive software once a designer gets used to it makes the design fast and flexible
34. de there are the connections used for the external switch used to connect to other devices of the manufacturing process from here and so on called chain out Moving to the right we find the connections to the buzzer which will be connected through a transistor just in case there s a need to change the chosen buzzer for a more powerful one Moving again to the right we find the connection to the button Finally on the right side at the bottom the encoder and its additional circuitry can be seen The microcontroller microcontroller of the console 15 the same as in the controller board and its features are the same as described in section 3 3 sensor controller The pins for the different devices attached to the microcontroller were chosen to get a good distribution on the PCB unless those that needed to be connected to specific pins like the port pins and the Pickit In Circuit Programmer Connectors for the controllers They will be WAGO 733 334 as described in the section 2 3 4 Control PCB Each of those connectors consisting in 4 pins will be have the first and the last pin connected to the 12VDC power rail and to ground respectively whereas the other pins will be for the communication between the console and the controllers ELECTRONIC DESIGN DIP switches Those are 8 contact 0 1 inch switches which will be used to conmute the functionality between dedicated ports to I2C bus for the co
35. ding to the sensor controller The chosen microcontroller for this development is the PIC18f4550 from the company Microchip The reason to choose this microcontroller is the wide previous experience of the designer with this microcontroller The software chosen for the development is the MPLAB X Integrated Development Environment provided for free by microchip The advantage of using this IDE instead of a generic one is the full integration with the microcontroller programmers Pickit2 and Pickit3 available for the designer also its code autocomplete capabilities and multiple file structure organization also the compatibility with several different compilers like CCS C18 or XC8 The compiler of choice for the previous development of this project was C18 but during the redesign process the designer decided to change this compiler for a more updated version which is up to date in difference with the C18 compiler which is currently deprecated for new projects and no more technical support provided The 8 compiler is based on the ANSI C standard with the addition of several specific libraries for the use of each specific microcontroller architecture from microchip so is possible to access all the peripherals of every device through C libraries instead of having to program them through assembler code SOFTWARE DESIGN 4 2 CONSOLE FIRMWARE main tasks of the console firmware are Configure and manage the user inte
36. e gearboxes the perform of a control system on the parts the assembly workers utilize during the assembly process is a must ensuring any part is skipped or assembled in incorrect order Through this the defective product ratio will improve improving also the productivity and the customer satisfaction PROJECT JUSTIFICATION 1 4 TARGETS The targets of the current project are the following Design the sensor system able to detect the movement of a hand inside the specified boxes Design the system to couple such sensors in a reliable way to the specified boxes Design the electronic circuitry needed in order to make the sensors work properly Design the software needed in order to make the sensors work properly Design the interface to connect such sensor system to a console which will control the overall assembly system Design the console circuitry Design the console software in a such way that is intuitive and easy to use Design the shape of the console in such way that is compact and reliable Design an I O interface to be able to change the configuration of the system Manufacture of a prototype Write a User Manual Provide technical support to the company whom acquires the system Design and implementation of manual assembly control system 1 5 SCOPE AND LIMITATIONS The scope of this project will be the utilization of the system in the assembly process inside the asse
37. e this Take in consideration a possible variation in the voltage to a 3 3V power source which means gt 3 3 0 006 470 Ohm so with a 1kOhm resistor we will get in the saturation area at the half of the maximum luminosity of the phototransistor Design and implementation of manual assembly control system Photoreceivers The photoreceivers are slightly more sophisticated devices than the phototransistors and include generally a block diagram as the one in figure 3 11 Instead of just sensing the IR light level the IR receivers need a modulated IR signal to be excited this has some advantages for example IR noise light immunity but also means the emitters need to generate this modulated signal BLOCK DIAGRAM Band Demo Control circuit 20445 1 Figure 3 11 Photoreceiver block diagram As can be seen on the block diagram the system has integrated pull up resistors so there s no need for external ones which will not be soldered in the control PCB when used with photoreceivers The device used for this project will be the TSOP77436 which has a modulation frequency of 36KHz The power consumption given by the datasheet of the device is 10mW what means a maximum of 80mW when all 8 receivers are powered Below the previously maximum consumption expected which was 100mW 3 8 WIRING The wiring between the sensors and the controller but also the wiring used to connect the
38. from the datasheet and is 10mW per device making total of 8S0mW ELECTRONIC DESIGN Phototransistors There are two different ways to use phototransistors as a linear device and as a switching device This depends on the voltage supplied an own characteristic of the phototransistors called collector light current which defines the maximum current through the phototransistor for the maximum lighting and the voltage applied The rule to define one or other mode 15 the following gt R Ica gt we never get into the saturation area so it works as a linear device lt R Ica gt at maximum luminosity we are saturated So the formula to calculate proper resistance will be gt Vcc Ica Using this formula with our given 6mA 5V gt 5 0 006 833 Ohm This is the minimum value to get into the saturation area with the maximum luminosity detectable by the phototransistor but by setting bigger the value of R is possible to switch the phototransistor at lower values of luminosity To set the proper value for the application some tests should be done but an approximate value of 1KOhm will be taken for the first tests The two problems that can arise through testing are The LED is not bright enough to saturate the phototransistor there s a need of a more powerful LED The environmental light saturates the device reducing the value of the resistor could solv
39. g on the final set value of the power regulator which could be 5 or 3 3 V but the calculations will be done taking in consideration the worst case 5Volt Those resistors will never dissipate more than 0 25W so it s possible to use common SMD resistors The transistors which will be of the type 2N7002 MOSFET topology transistors with this characteristics Symbol Parameter Conditions Min Typ Max Unit Vps drain source voltage 25 C lt Tj lt 150 60 V Ip drain current Vos 10 V Tsp 25 C see Figure 1 300 mA see Figure 3 total power dissipation Tsp 25 C see Figure 2 083 W Static characteristics Rpson drain source on state Ves 10 V Ip 500 mA T 25 2 8 5 resistance see Figure 6 see Figure 8 Figure 3 5 2n7002 characteristics The reason to choose those transistors is they are widely available matched switching speed for the application power dissipation matching the application not excessive on resistance no fixed voltage drop in the junction in contraposition with the BJT topology and good price ELECTRONIC DESIGN A capacitor to absorb possible voltage spikes that can generate unexpected behavior in the microcontroller more information about this can be found on the microcontroller datasheet Connector for the receivers Same as in the case of the emitters IR LED s will connect to the receivers PCB there s also an extra pin which is connected to an anal
40. ices around europe and asia and besides the wish of the designer to manufacture the PCB s in the EU but the price difference is so humongous comparing to the Asian market that was impossible to the designer to afford EU manufacture Hand soldering For the prototypes the part assembly process and soldering was handmade due to the excessive cost for a small production through other methods like the pick and place system Pick and place The pick and place systems are the preferred for a medium to high production quantities it gets discarded for the prototypes due to the high initial costs of the technology Those systems automatically place all the components over the PCB which will be afterwards soldered inside a PCB oven Let us see an example of this machines in the figure 5 4 Figure 5 4 Pick and place machine TESTS AND MODIFICATIONS 6 TESTS AND MODIFICATIONS Design and implementation of manual assembly control system 6 1 PROBLEMS ON THE BASIC FUNCTIONALITY 6 1 1 HOT PLUGGING AND NTC S In lots but definitely not in all modern electronic systems is possible to directly plug some parts of the device while it s connected and working This action is known as hot plugging When designing the device described on this project it was never taken in consideration but simply expected to work on this way If plugging directly the sensor boxes onto the console the power draw of the boxes
41. le outgoings which will be used to fix the control box to the sensor boxes The square hollows on both sides will be used to insert them and together with the Control Box Top will give the right fixation For the same reasons previously mentioned the overall thickness of this part is also kept to 1 5mm The outgoings could represent a problem in the simplicity of the design of a plastic injection mold Figure 2 8 Detail on control box bottom because they could be seen as generating undercuts but they were designed with a size small enough that allows the parts to be sprout from the mold with the help of ejectors MECHANICAL DESIGN 2 3 3 SENSOR BOX LEFT RIGHT In the case of the sensor boxes the design of both is the same but inverted through the x axis So we will describe them together Pay attention to the figure 2 9 to notice their characteristics Figure 2 9 Sensor box left side The interesting points about the design of this part are the following The square on the left to fix it to the Control Box Bottom and Top The small keystone shaped cavities along all the part used to fix the sensor glasses The central pillar on the big cavity which accomplishes a double function avoid the part to get very deformed due to the injection molding process and hold the sensor receiver PCB Finally There is a flap on the top of the part with similar characteristics as the one in the original co
42. limiting resistors on the left bottom A filter capacitor for the power of the microcontroller also on the left bottom The pull up resistors for the communication with the console the power regulator a filter capacitor for the power regulator and the connector to the console The microcontroller As will be described in the further software sections the device is a 8 bit microcontroller PIC18f4550 from the company Microchip here you can find listed some of its characteristics Design and implementation of manual assembly control system Universal Serial Bus Features USB V2 0 Compliant Low Speed 1 5 Mb s and Full Speed 12 Mb s Supports Control Interrupt Isochronous and Bulk Transfers Supports up to 32 Endpoints 16 bidirectional 1 Kbyte Dual Access RAM for USB On Chip USB Transceiver with On Chip Voltage Regulator Interface for Off Chip USB Transceiver Streaming Parallel Port SPP for USB streaming transfers 40 44 pin devices only Power Managed Modes Run CPU on peripherals on Idle CPU off peripherals on Sleep CPU off peripherals off Idle mode currents down to 5 8 uA typical Sleep mode currents down to 0 1 uA typical Timer1 Oscillator 1 1 uA typical 32 kHz 2V Watchdog Timer 2 1 uA typical Two Speed Oscillator Start up Flexible Oscillator Structure Four Crystal modes including High Precision PLL for USB Two External Clock modes up to 48 M
43. limiting resistors for the IR LED s were replaced for 8 2kOhm resistors 6 3 7 TEST 7 DRIVING LED S WITH LOWER CURRENT After the replacing of the limiting resistors with the new value of 8 2kOhms a finger can easily break the beam of the IR LED s The number of receivers excited for each LED still isn t only one but three Besides this the excited receivers always follow a predictable pattern being the adjacent ones on both sides what means that in the corners only two receivers are excited This fact can become an extra feature if properly managed by software because it allows to detect if the oblique beams gets cut which could allow to measure the size and the position of the object cutting the beam Besides the system is already useable there are some problems driving the last two IR LED s on the outer side of the container which aren t working properly Design and implementation of manual assembly control system 6 3 8 TEST 8 LIGHT SOURCE INTERFERENCES Two possible light sources which can cause interferences on the receivers are the fluorescent lamps and the IR remote controls To check if the receivers were catching these interferences a fluorescent lamp was disposed as close as possible to the receivers focusing its light directly to the receivers There wasn t any difference in the functionality of the system while the fluorescent lamp test An IR remote control was also used to interfere with the receive
44. lue by default so it MUST be tested and calibrated before soldering on the PCB or it may cause damage to the circuit Filter capacitor for the power regulator Used to hold the voltage stable on the controller side in case of abrupt changes on the power consumption 3 5 CONSOLE Let us proceed with the console in the same way done with the controller starting with the schematic to show the different parts of the design 235522278 000 733 364 Document Number Date 27 07 2015 1912813 Sheen 1 1 Figure 3 6 Console Schematic As can be seen in the figure 3 6 The circuit contains The microcontroller at the center Design and implementation of manual assembly control system A connector to in circuit programmer power and the run LED s with its current limiting resistors with the recommended capacitor for the microcontroller power supply on the center top On the left side can be seen the connections to the four controllers and also some switches which will be used to reconnect the pins of the boxes to the I2C port feature that could be used in future versions At the right side on the top can be seen the power supply and a voltage regulator plus the connector to the power plug Below those can be found the I2C port connection used for the communication with the 1602 LCD At the bottom on the left si
45. mable under Software Control Priority Levels for Interrupts 8x8 Single Cycle Hardware Multiplier Extended Watchdog Timer WDT Programmable period from 41 ms to 131s Programmable Code Protection Single Supply 5V In Circuit Serial Programming ICSP two pins In Circuit Debug ICD via two pins Optional dedicated ICD ICSP port 44 pin devices only Wide Operating Voltage Range 2 0V to 5 5V Figure 3 3 PIC18f4550 features So as can be seen in the figure 3 2 the 1814550 has 35 I O pins from which we will need 8 pins for the activation of the IR LED used as emitters 8 pins for the sensing of the receivers 2 pins for the communication with the console pin for the run LED which will blink while the device is active There will be the need of using other IO ports which have a multiplexed functionality to use through them the in circuit programmer Those pins need to be necessarily the pins 16 17 and 18 as can be seen in figure 3 3 which will not be available as IO ELECTRONIC DESIGN 39 Also the pins assigned to the communication with the console are fixed to be coincident with the I2C port of the microcontroller regarding to a possible future modification to use all the controllers unified in a single I2C bus Also can be seen the connection of some pins to a device called wireless This device is an NRF24L01 wireless communication module which will not be described further because i
46. mbly facilities of the company This system is not intended to be used outdoor This system is not intended to be used in areas with high ambient particles level like milling machining facilities This system is a PROTOTYPE so it may need further modifications to work properly but needs to be tested on the field for a long time to let the possible problems arise 1 6 STRUCTURE This project will be mainly divided into three different fields of interest Electronic design Mechanical design Software design But will also include some other sections but related in some way with those previously mentioned topics as the following Prototype and mass production System testing Mechanical drawings 2 MECHANICAL DESIGN UI9 s s A quiesse enueur Jo pue 2 1 INTRODUCTION Regarding to the mechanical design the system has two differentiated parts with their own targets and limitations the console and the controller Talking about the controller the main needs are to design the housing to contain the sensors and the control logic unit in a way that they get adapted to the chosen container minimizing the impact on the inherent functionality of the container and letting use the added functionalities with ease and this means Create a design which doesn t need to modify the container itself to be used Design the housing on a way th
47. nd release 6 1 3 CONNECTORS During the testing phase some problems with the IR LED shown up they were randomly working depending on the position of the PCB which in the beginning look like a crimp problem the designer had to crimp all the wires on his own with tools which were not adapted to this kind of connectors which is an inherent focus of troubles and errors but at the time it was simply the only possible option Finally emerged the real cause of the problem which was a bad solder another of the most common problems due to the hand soldering of very small components done by the designer 6 1 4 IR LED EXCESSIVELY POWERFUL On the calculations for the current draw for the LED s was taken the maximum possible brightness of those thinking that this would be the best option to improve the reliability of the beams but several problems came into view The excess of power of the LED s were causing lots of reflections inside the containers which meant that all the receivers were active every time an LED was flashing There s a consideration ignored before which is the fact that HUMAN FLESH IS ALMOST TRANSPARENT TO IR LIGHT What means there s a need to emit at very small power so the goal of detecting a hand inside the containers is accomplished 6 1 5 ERROR IN THE PCB LAYOUT There was an error in the footprint of the VTX 214 010 112 device the issue was footprint was mirrored so the power supply could be properl
48. ns Main Controller Initialize variables toggle ToggleLED toggle yes ON _ OFF LED OFF LED ON d hand Sense other CONSOLE_WIR Delay up hand Sense CONSOLE_WIR 0 Figure 7 13 Flowchart of the main function of the controller FLOWCHARTS 9 Initialize variab SENSE LED N i RECEIVER_N 1 lt nPulses gt nPulses Y Y i nOn 0 IR_LED i 1 1 1 gt res Receiver i threshold Return ret TOGGLE LED Figure 7 14 Sense and Toggle LED functions Design and implementation of manual assembly control system 5 enueur pue COSTS 8 COSTS MATERIALS PROVIDER bru y rubio fab lab berlin fab lab berlin fab lab berlin fab lab berlin Franz Brose Max witte modulor fab lab berlin fab lab berlin segor segor ebay ebay ebay 8 1 DEVELOPMENT COSTS ITEM Tayg 51 box container FDM prototype Control Box Front FDM prototype Control Box Back FDM prototype Sensor Box Right FDM prototype Sensor Box Left IR transparent acrylglass 9C20 sample Screw M2 5 x 10 DIN 965 Acrylglass 120 x 250 mm FDM prototype Console top FDM prototype Control Box Back Electric Keyswitch Rocker switch MARQUARDT 1801 1121 C7 IEC power plug 1602 LCD screen ICD
49. nsole box bottom Material ABS Black Console PCB including materials Controller PCB including materials Emitters PCB including materials Receivers PCB including materials Console box front acrylglas laser cut Console box back acrylglas laser cut IR glass Control box front Material ABS Black Control box back Material ABS Black Sensor box left Material ABS Black Control box right Material ABS Black 1000 1000 1000 1000 250 250 250 1000 1000 1000 250 250 2000 4 31 2 05 1 97 1 97 5 55 4 31 18 55 3 82 5 32 4 66 0 961 0 96736 0 56 4 31 2 05 1 97 1 97 4310 2050 1970 1970 1387 5 1077 5 4637 5 3820 5320 4860 240 25 241 84 1120 71479 79 17 24 8 2 7 88 7 88 COSTS TOTAL Console box top Material ABS Black Console box bottom Material ABS Black Console PCB including materials Controller PCB including materials Emitters PCB including materials Receivers PCB including materials Console box front acrylglas laser cut Console box back acrylglas laser cut IR glass 5 55 4 31 18 55 3 82 5 32 4 86 0 961 0 96736 0 56 5 55 4 31 18 55 15 28 21 26 19 44 0 961 0 96736 1 12 128 6584 Design and implementation of manual assembly control system UI9 s s A quiesse enueur Jo pue
50. ntainer with the finality of keeping the original functionality of the container being able to stack several boxes even when they have the sensor system installed In this case the overall thickness of the part is a little lower 1 mm due to the need to optimize the space bound by the size of the PCB which is determined by the size of the connectors for the wiring of the emitters receivers Design and implementation of manual assembly control system 2 3 4 SENSOR GLASS The so called sensor glass isn t really a glass but a 1mm thickness sheet of acrylglass named with the reference 9C20 which is transparent to a wide range of the IR light spectrum as is possible to notice in the figure 2 10 Transmission of ACRYLITE GP Sheet Color 1146 0 and 199 0 100 90 60 Light Transmission Percent Cn e 200 400 600 600 1000 1200 1400 1600 1800 2000 Wavelength nanometers Figure 2 10 Light transmission of the IR glass against wavelength This part is designed to be completely flat as can be seen on figure 2 11 to avoid possible undesired reflections of the emitters having also an added advantage for the manufacture The process to manufacture this part is slicing with a laser cutter from a big dimensions sheet Is also possible to appreciate the keystone shaped outgoings to fix it to the above mentioned Sensor Box Figure 2 11 Sensor glass
51. ntroller boxes While all of the switches of one package are on all the switches on the other package must be off Figure 3 7 DIP switches Power supply The power supply will be a VIGORTRONIX 214 010 112 which will convert the 230V AC from the net in 12VDC used to deliver the power to the sensors which will be afterwards converted in 5 VDC to power the circuitry of the console 12 Port and 1602 LCD Through this connector attached to the I2C port of the microcontroller which will also be a WAGO 733 series connector the console circuitry will connect to the 1602 LCD used to display information to the users The LCD has an external circuitry attached to it allowing to communicate by means of I2C protocol The drivers for this device were written for another project by the designer of this project Switch and encoder Used as input devices from the user they have some extra external circuitry to perform a HARDWARE DEBOUNCING to avoid multiple detections due to the mechanical parts contained in the button and in the encoder The encoder 15 QUADRATURE DOUBLE STEP rotary encoder In the figures 3 8 and 3 9 can be seen the signal generated for this encoder while rotating clockwise and anti clockwise Design and implementation of manual assembly control system 0 CLOCK Figure 3 8 Encoder turning counter clockwise two steps 0 CLOCK Figure 3 9 Encoder turning clockwise two steps From
52. of this configuration will be the same as the previously explained in the section 4 2 2 6 but with a different maximum and minimum ranges 4 2 2 9 Sound Allows to set the alarm sounds active inactive depending on the preferences of the user and Down will toggle the option whereas the Enter button saves the option and quits and the back button quits without saving Design and implementation of manual assembly control system 4 2 2 10 Error Statstistics Inside this option is possible to check the number of faults committed after the last counter reset To reset the counter turn the encoder left turning right has no effect Enter and Back options share the same behavior going back to the configuration menu note In future versions of the software there will be several other error statistics SOFTWARE DESIGN 4 2 3 ASSEMBLY PROCESS AND SYSTEM LOCKING The assembly process which is the main aim of the design is thought to proceed as in the flowchart given in the 7 6 but let us explain it normal language Once the machine is switched on with the locker closed the only available options are the firmware and the assembly start pushing Enter on the assembly start options the system will show the number of a box from which the worker needs to extract a part and it will continue showing the same box number until as many parts as needed for the assembly are extracted Then the number of box will change
53. og pin just in case it s needed in future revisions Pull down resistors The pull down resistors are set to be used with the phototransistors and the system is thought to use them as switches which means its value must be taken from the equation gt R Ia being Ia the value of the light current and R the value of the pull down This gives a value of R gt 5V 6mA R gt 866 Ohm Anyway this is only an indicative value to use as start point for the test phase In the case of the modulated photoreceivers as it will be explained in the section 3 6 there will be no need of those pull down resistors Power and run LED s If the system is powered on the power LED on this case white will light up if the microcontroller is also active the blue run LED will blink The maximum allowed current through the LED s is 20 mA extracted from seller s information but taking in consideration there s no need to use the maximum brightness but to optimize the power consumption the maximum current will be set to 4mA so the resistors value will be Rlim Vcc Vak Imax 5 3 2 4mA Rlim 450 Ohm Design and implementation of manual assembly control system chosen value will be the closest standard resistor value 470 Ohm And the power consumption will be PzV I P 5 4mA P 0 02W Capacitor for the power of the microcontroller This capacitor is used to avoid high frequency ripple on
54. onnectors were placed to serve internal device connection like the screen or the locker The size of the power supply orange on figure 2 25 was in the initial stage of the design the most limiting factor for the size of the console 2 4 4 OTHER COMPONENTS Locker The locker figure 2 27 is a standard SPST key switch with a 19 5 mm mounting hole which can be provided by several manufacturers There isn t any Figure 2 27 Locker keyswitch Design and implementation of manual assembly control system datasheet for this part so it will be replaced in case of a further versions to ensure technical characteristics Placed on the front panel to give easy access to the supervisors to change the options Screen This screen is a 1602 LCD widely used along consumer electronics devices which can be manufactured in very different sizes and shapes but most of them have the same dimensions so they re compatible with each other the dimensions are shown in figure 2 28 Placed at the center of the front side to make easy for the users to read the displayed messages Encoder and button The encoder is a ready to use KEYES module easy to find on EBAY probably based on a TYCO DP12SV encoder There lots of different encoder modules with the same dimensions so it is easy to find other models which fit the same dimensions figure 2 29 Figure 2 28 1602 LCD screen Figure 2
55. p side will have a couple of plugs to fix the buzzer Figure 2 23 Console box bottom Figure 2 24 Console box top Design and implementation of manual assembly control system Figure 2 25 Top and bottom sides including PCB and buzzer 2 4 3 CONSOLE PCB Regarding to the mechanical design the main point of interest is the location of the connectors and the I O devices As much as can be directly attached to the PCB as better so it will give robustness and reliability but the fact is that is much more important to give the right position to the I O devices so it becomes easy to interact with the system As can be seen in figure 2 25 the rear connectors used to connect the console to the sensor controllers and the chain connector used to connect to other machines part of the assembly process are the only components on the back side which are to be used outside the housing of the console On the front side the encoder is the only part which protrudes the console case MECHANICAL DESIGN the rest of the components needed to be air wired and connected to PCB Figure 2 26 Console PCB In the initial stage of the design the connectors to the sensor controllers were on the front side but once the wiring is connected makes uncomfortable to work with the I O devices and also implied to make the PCB much longer the same way as the housing the rest of the c
56. plastic filament which conforms the parts It s a method with low reliability and low quality prints but is far away the cheapest in terms of machinery and material This will be the method used for the production of the following prototypes om om Console box top console box bottom control box top om control box bottom sensor box right and sensor box left Figure 5 2 FDM printed part Injection molding For a possible mass production the preferred production method for the 3D printed prototyped parts will be the injection molding This has some implications on the mechanical The final noe urs design of parts like minimizing undercuts and draft all the parts to ensure the demoldability Those and other requirements can be seen on the included offers used also for the costs estimation Figure 5 3 Injection molding Design and implementation of manual assembly control system 5 2 PRINTED CIRCUIT BOARDS Gerber files The first step to manufacture a PCB usually is to get from your preferred PCB design software the GERBER files which is a de facto standard for the PCB production Usually there s also the need to add the Excellon files which refer to the drilled holes PCB Manufacture Once the CAM files are ready there are lots of different online service in which you can manufacture the PCB s for this project the designer checked several serv
57. re 2 4 two hollows in which the connectors of the electronic circuitry will fit which use will be to connect with the console and to have easy access to debug update the firmware of the sensor controller Figure 2 5 Control box top inside lFigure 2 4 Control box top outside On the other side is also possible to appreciate the cavities and outgoings that will be used for the fixation with the other parts comprising the sensor controller Figure 2 6 The width of this part is determined by the size of the chosen connectors trying to keep it as small as possible not to disturb the form factor of the container The thickness of the material will be kept in 1 5 mm which gives robustness and flexibility without an excess of material use Figure 2 6 Detail on control box Design and implementation of manual assembly control system 2 3 2 CONTROL BOX BOTTOM The Control Box Bottom part will hold the PCB and is also the one which fixes it to the container it contains a hollow to get fixed through the back flap of the container and several holes to fix the PCB by means of screws those laying inside the box not disturbing the overall look of the cases as can be seen in figure 2 7 also Figure 2 7 Control box bottom inner view 15 possible to appreciate the profile of the case which is adapted to the backside of the container e On the figure 2 8 is possible to see again the litt
58. rface which consist in several input and output devices to be controlled by the user or to display information to acknowledge the user Give access through the user interface to all the configuration parameters to be used in the different assembly types Control the assembly process meaning this to check if the assembly workers take the right amount of parts and on the right order to get a correct assembly Block the assembly system in some way not allowing the assembly workers to continue with the process before the supervisor checks the assemblies which could give place to an error Design and implementation of manual assembly control system 4 2 1 USER INTERFACE Those are the input devices the users can access to Encoder with button Turning this device right or left the user can go through the different menu options pushing the button contained in the encoder starts the selected process for example to start the assembly process or to change the configuration parameters Secondary button Pushing the button returns from the current option back stopping the process without saving any information changed Together with the Encoder with button is enough to move back and forth through all the console options Locker The locker is used to avoid the assembly workers to change the different configuration options so once the locker is closed all the configuration functionality disappears f
59. rom the console options The menu options are intended to be only user by the supervisors to properly set up the machine and to unlock it in case there s any mistake in the assembly SOFTWARE DESIGN And those the output devices Screen Used to display most of the relevant information of the system also to navigate through the different options Most of the screen handling is hidden in flowcharts due to the fact the libraries used to manage such events were programmed by the designer but are generic for different projects so they re out of the scope of this text Power LED Simply a white LED which shows the system is already powered on Run LED Colored led which blinks while the microcontroller is performing tasks so if the LED stops blinking means the system got stuck Useful for debugging tasks but also just in case there s a critical error during the process the user can appreciate the machine is stuck and restart it Buzzer Used during the assembly process to acknowledge the assemblers the detection and also to be used as an alarm when there s a fail in the assembly process Chain relay The designed console could be connected also to other devices that are checking other parts of the assembly process and this is the way they communicate When the contact change from its normal state it means there s a problem in the process and it will only return to the original state when the supe
60. rs pointing the emitter to them While in a long distance the remote control doesn t affect to the receivers but in a very short distance the emission of the remote control can cause interferences generating false positive and false negative detections but if the distance between the remote control is more than approximately 500 mm the interferences are not powerful enough to interfere with the receivers The conclusion is that the interference level to cause a malfunction in the receivers by fluorescent light is negligible and the interferences caused by a remote control are not intended to be in the scope of the system and much less as close as they need to be to cause such interferences UI9 s s A quiesse enueur Jo pue 7 FLOWCHARTS SLV LS DIINOO NYO AES RA ARS aNNOS DIANO ANNOS ACISNISWIL X ACISNI WIL DI NO saxog AWIL SAXON DIINOO xOd add ANN DIINOO A IHINHSSV lt Udy pue suondo o qe reAe MOUY 0 ANIONS aui JO ourauos V ATUO SI 200 SI SUL NOLLNALLLV A ISINSSSV LIVIS TANLONALS TET NANNAN Menu structure Figure 7 1 UI9 s s enueur Jo pue
61. rvisor unlocks the system through the locker Design and implementation of manual assembly control system 4 2 2 MENU OPTIONS AND CONFIGURATION PARAMETERS the configuration parameters explained in this section will be stored in global variables so there s easy access to them from any part of the program In the figure 7 1 can be seen the different options through which the user can navigate Let s get a little bit more in detail about those options 4 2 2 1 Firmware version Allows you to check the current firmware version installed in the device in case the company which ordered the project decides it on that way this could be changed to a text displaying the name of the company or any other text 4 2 2 2 Assembly start Shows on the screen the possibility to start the assembly pushing the enter button starts the assembly process 4 2 2 3 Assembly Once here we are inside the assembly process itself and it will be ruled by the flowchart attached within the figure 7 6 4 2 2 4 Configuration menu Allows the user by pressing the enter button to get inside the configuration menu letting the user move through the different options Attention The Configuration menu is not intended to be used by the workers involved in the assembly process but for the supervisors so this menu will be hidden while the locker stays open SOFTWARE DESIGN 4 2 2 5 Configuration option display The options going from NUMB
62. s a future modification out of the scope of this project so it only be again commented in the modifications section The pins where to connect the IR LED s and the photo sensors were chosen to be adjacent and easy to route regarding the disposition of the elements in the PCB as can be seen in the figure 3 4 9 9 9 9 9 9 9 9 9 9 9 9 9 9 0 9 9 09 9 9 9 9 9 0 9 9 9 09 9 9 09 0 0 0 0 0 09 0 0 0 Figure 3 4 Controller Once the IR LED s and the sensors were correctly assigned to pins then the rest of the pins were chosen so the final allocation of the pins became as seen in the schematic The connector to the in circuit debugger Design and implementation of manual assembly control system Contains five pins according to connectors that need to be done with devices pickit2 or pickit3 those pins are power ground programming clock programming data and master reset to set the device in the programming mode The connector to the IR LED s Already described and justified in the mechanical design section left to say that it contains 11 pins besides it needs only 10 to match the connector used on the side of the sensors The current limiting resistors for the IR LED s As their name explains are used to limit the maximum current through the LED s to its maximum value which is 100mA its value needs to be adjusted dependin
63. sistors used on the I2C data and clock pins and the length of the wire used by the communication Decreasing the speed of the clock signal will also improve the reliability of the communication 6 2 3 POSSIBLE WIRELESS COMMUNICATION A possible wireless communication between the sensor controllers and the console was taken in consideration adding to the controllers a Lithium Polymer battery could avoid the need of wiring the system giving a much better flexibility It s possible to notice the footprint of and NRF24L01 on the controller PCB which was the device intended to be used for that communication Due to the high power consumption reduction on the IR LED s commented in section 6 1 4 this option is much more feasible so if there s a redesign on the project will be oriented on this way 6 2 4 SPI COMMUNICATION The previously mentioned NRF24L01 communicates to the microcontroller through SPI port which in the actual microcontroller isn t compatible with the I2C communication which implies to change the communication protocol between the LCD screen included in the console and the microcontroller to I2C this can be easily done using another PCB previously designed just replacing the I2C for the SPI module on the back side of the screen 6 2 5 CHANGE TO ARM ARCHITECTURE The change in the architecture of the microcontroller is one of the most critical possible changes because it will imply a very deep redesign in the proje
64. system CHA LOANNOO SHXOHG 5921420 I 12990 v poj 2uuo JONXOg 0 ye A 3Anoe p21223uuo Pe NP lt 0 A 0 c 2 E JONXOg A I gt QD po122uuo JONXOg A 9ADO UI pa1 ouuo2 saxoq 32205 Flowchart of the process to check if all defined boxes are connected Figure 7 11 2 2 298 HS vd Ke dsiqq 2 jou Ke dsiqq 10N 1dniojug s dniiojut 59 jqeuq NNA AAT 218801 USI ITI URIS GELO sjndjno 196 aindguo se 3104 2113 p sdej USI 0 FOUL INO Id 34 uoneinsguo2 180 enueu jo pue Figure 7 12 Flowchart of several used functio
65. t of the main function of the controller 90 Figure 7 14 Sense and Toggle LED 91 INTRODUCTION INTRODUCTION The following project is the redesign of a former project ordered by a company to the writer of this project which wasn t totally successful on the first try so it was a challenge to find the way to make the system more robust and reliable as close as possible to a real commercial product In this project there are three main fields which will be combined along it electronics mechanics and programming The mechanical design part which was the main handicap of the designer during the development of the project in which is based the following will be greatly improved Also there was an improve in the electronic design skills but over this the research and component identification of the designer have improved during the period of time between the development of the old and the new project Probably the part in which the designer didn t improve enough to mean a notorious change from the former project is the programming but anyway the process of redesigning the system had as a consequence in the designer to find a new way of thinking about the programming problems and how to approach them It s important to note also the skills acquired regarding to the acquisition of materials and the relations with the providers Design and implementation of manual assembly
66. tains the same fixing holes as the front Figure 2 18 Console box front frontal view Figure 2 19 Console box front with assembled parts Design and implementation of manual assembly control system Figure 2 20 Console box front top view with assembled parts Figure 2 21 Console box back inner view Figure 2 22 Console box back outer view Is important to note in the first design phase the connectors to the sensor controllers were in the front side giving easier access to them but after thinking deeply on the usability of the console was decided to move them to the back side so the wires are not interrupting the easy access to the button encoder and screen which will become the center of the interaction MECHANICAL DESIGN Both parts were designed using a flat surface with the intention of manufacturing them with a sheet of 3 4 mm plexiglass or plywood through laser cutting process inasmuch as the designer has access to such laser cutter for those materials and is also a very easy and cheap manufacture method due to the lack of need of a mold unlike in casting processes 2 4 2 BOX TOP AND BOTTOM The top and the bottom part will have a similar geometry they will fit on each other housing all the console circuitry and will be fixed through screws to the front and the back side The bottom side will contain four plugs to fix the PCB through screws in the same way the to
67. termine Figure 7 7 FLOWCHARTS Config N of parts CONFIGURE variables PARTS Print box number functionN MENU CONFIG Print number of parts 0 D down U up enter Y Y Y Y nParts box nParts box 1 1 gt 20 lt 1 nParts nParts 20 1 20 MIN 1 nBoxes Figure 7 8 Configure number of parts flowchart Design and implementation of manual assembly control system Config Time in box tInBox Config NumVal Save on EEPROM functionN Config Nboxes MENU CON Config Sound FIG Y Y sound ConfigBin Val nBoxes Config NumVal Y Save on EEPROM Save on EEPROM tInBox nBoxes functionN MO MENU CON unctionN G FIG Config Statistics Return nErrors Config Resettable Val Save on EEPROM nErrors CONFIGURATION functionN MISCELLANEOUS MENU_CON FIG Figure 7 9 Flowchart of miscellaneous configuration options FLOWCHARTS ERROR HANDLER Error Handler Initialize Variables errorType Display Display TIME TIME IN BETWEEN 210 EXPIRED EXPIRED Display Display INCORRECT MULTIPLE BOX DETECTION functionN MAIN_MENU Figure 7 10 Error handler flowchart lt lt Design and implementation of manual assembly control
68. the power of the microcontroller to avoid parasitic resets holding the power stable The recommended taken the reference of similar designs with a 18F4550 is 150 pF but similar values will also work properly Pull up resistors for the I2C communication Those pull up resistors are placed to ensure the voltage reference on the communication pins between the controller and the console considering a possible future modification to communicate both devices through the I2C protocol two 4 7 KOhm resistors will be used which is a commonly used value for the I2C taking in consideration the I2C bus will be used only in low speed mode Power regulator The voltage supplied by the console is 12 Volt to transmit more power with less loses through the wires which connect the console and the controller but the voltage needed for the controller circuitry is from 3 3 to 5 Volt so there s a need for a step down voltage regulator In this case the voltage regulator will be a MINI 360 step down switching regulator which is able to convert a voltage up to 23 Volts to a lower voltage as low as 1 Volt so it will be able to deliver both 3 3 and 5 Volts to the controller circuitry just setting up the right value with the potentiometer included on the regulator This circuit also shields the partially the possible voltage drops on the console to affect the controller circuitry ELECTRONIC DESIGN IMPORTANT NOTE the regulator is set to its maximum va
69. this graphs taken with a logic analyzer the designer programmed the driver to use the encoder as the input device for the console Other All the non described items have the same characteristics as in the section 3 3 3 6 EMITTERS PCB The emitters PCB will consist in the IR LED s and the connector to the controller The description of the connector was already given in the section 2 3 5 so there s only left to talk about the LED s which are VSMB2000X01 some of its characteristics are Peak wavelength 940 nm infrared range High radiant power Angle of half intensity 12 Dimensions 2 3 x 2 3 x 2 8 ELECTRONIC DESIGN And those were the main reasons to choose this IR LED to keep the form factor of the device as small as possible there was a need of small devices and was important to keep the angle of the beam as small as possible to avoid interferences with the receivers The anode of the IR LED s is connected to Vcc while the cathode is connected to the drain of the FET s from the controller unit so when the FET s are active the cathode gets connected to ground and the current flows limited by the current limiting resistors So let s check the power consumption of the emitters Taking this data from the datasheet 100mA IFM max 200mA maximum continuous forward current and peak Vfmin 1 15V if the Voltage supplied to the LED s is 3 3V 3 3V 1 15V so
70. way from a raw sheet of material It s possible to get the parts directly from the machining provider or to get the raw material and pay the laser cutting service per given time In the case of this project the designer had the access to a Laser cutter and had the knowledge to use it so the 4 prototypes were manufactured in a timed service The parts prototyped with this method are console box front and console box back Figure 5 1 Laser cut acrylglas In the case of a mass production is always better to outsource the service and relay in the hands of professionals it will be easier and cheaper 3D printing FDM The definition of 3D printing is a vague conglomeration of very different manufacturing techniques with something in common they re additive techniques and this means that instead of removing big quantities of materials from a raw block they add small quantities until the desired part is generated Three examples of these techniques are SLA Stereolithography which uses a laser to cure a photosensitive polymer by layers a slow method with very few and expensive material choices but good print quality PROTOTYPE AND PRODUCTION SLS Selective Laser sintering Generates the part melting selectively polymer dust Giving parts of good quality small tolerances but rough surface finish FDM Fused melted deposition The additive manufacturing most diffused method using an extruder to melt a
71. y connected on the other side the problem is doing so means the dimensions of the PCB change totally making impossible to fit inside the console box This problem was solved soldering wires to the power supply to replace them on the solder of the PCB The proper way to solve this problem would be to modify the footprint and redesign the but there was no time to wait for the manufacture of the new board so the designer of this project decided to go forth with the current PCB design Design and implementation of manual assembly control system 6 2 FURTHER MODIFICATIONS 6 2 1 CONNECTING MORE SENSOR BOXES There is the possibility to connect more sensor boxes performing a modification in the software and adapting the wiring between the console and the controllers using the second I O pin every box port has available currently used to ensure the boxes are connected 6 2 2 USING I2C PORT TO CONNECT WITH THE CONTROLLERS This possible modification was taken in consideration from the beginning of the design of the PCB s so by means of the internal DIP switches on the console PCB is possible to connect all the controller box ports to the console in a way that they can make use of the I2C port communication This feature wasn t tested due to the lack of time before the deadline of this project One of the expected problems of this method will be the maximum allowed wire length which depends on the value of the pull up re

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