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ECE 477 Design Review Team 5  Fall 2009

ECE 477 Design Review Team 5  Fall 2009. Ben Carter – Jacqui Dickerson – Ian Oliver – Dennis Lee. Outline. Project overview Project-specific success criteria Block diagram Component selection rationale Packaging design Schematic and theory of operation PCB layout

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ECE 477 Design Review Team 5  Fall 2009

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  1. ECE 477 Design Review Team 5  Fall 2009 Ben Carter – Jacqui Dickerson – Ian Oliver – Dennis Lee

  2. Outline • Project overview • Project-specific success criteria • Block diagram • Component selection rationale • Packaging design • Schematic and theory of operation • PCB layout • Software design/development status • Project completion timeline • Questions / discussion

  3. Project Overview • Next generation communication system for vehicles • Simple, real-time visual communication • Multi-touch input • Driver’s gestures produce an output on LEDs around the perimeter of a car • Color-coded messages • Tri-color LEDs produce blue, green, yellow, orange, and red outputs

  4. Example Gestures • 1) 2 fingers swiped right - Green LEDs in front of car slide right; signal to a pedestrian walking right that it's okay to pass2) 3 fingers swiped up – Yellow LEDs on front of car illuminate; signal that driver in oncoming lane is entering a hazardous area3) 5 fingers swiped down - Red LEDs in back of car blink; signal that car behind driver is tailgating/back off4) 1 finger swiped down - Blue LEDs in back of car blink; signal to thank car behind driver for letting driver merge

  5. Project-Specific Success Criteria • 1. The ability to determine direction of a finger swipe on a touch pad array. • 2. The ability to determine the number of fingers used on a touch pad array. • 3. The ability to produce at least two meaningful LED patterns. • 4. The ability to determine force of acceleration on a car. • 5. The ability to wirelessly transmit data from the multi-touch signal processor to the LED cluster controller

  6. 30 Capacitive Touch Inputs 30 Capacitive Touch Inputs 30 Capacitive Touch Inputs 30 Capacitive Touch Inputs 30 30 30 30 5 More CapSense Controller 0 CapSense Controller 1 CapSense Controller 7 CapSense Controller 8 I2C Microcontroller/DSP (Gesture Recognition) I2C LED Driver 0 LED Driver 3 UART Tx 2 more 15 15 RF Transmitter 5 tricolor LEDs 5 tricolor LEDs RF Communication @ 315MHz RF Receiver 0V – 5V analog UART Rx Microcontroller 0 (LED Control) Accelerometer I2C LED Driver 0 LED Driver 13 12 more 15 15 5 tricolor LEDs 5 tricolor LEDs

  7. Component Selection Rationale dsPIC33FJ256MC710 Required a lot of RAM & moderate Flash Signal processing 270 point scans of touch surface 2-I2C and a UART interface PIC18F2525 Required modest amount of RAM and Flash I2C and UART interfaces dsPIC chosen; staying w/ same family LED Drivers (TLC59116) Required 15 PWM channels to control 5 tri-color LEDs I2C interface provides ability to control up to 14 LED drivers using 2 pins

  8. Component Selection Rationale • RF Transmitter/Receiver (MO-SAWR-AS315M/MO-RX3400-A315M) • Required 315MHz • Provides up to 100m of transmission • Accelerometer (MMA1270EG) • Required 2.5g over 1 axis • SOIC packaging for ease of soldering • Capacitive Touch Input Controllers (CY8C20566) • Required many (30) touches to be realized • Donated by Purdue Alum & Cypress FAE

  9. Packaging Design Constraints • Will not be demonstrating on a full size vehicle • Large RC car will house one LED Output Cluster • User Interface Module will be exterior to car, powered by an AC wall wart • Full size design would consist of several LED Output Clusters, weatherproofing, and a scheme for mounting the User Interface Module to a steering wheel

  10. Packaging Design – User Interface Module • 8”x8”x1-1/2” • *variable • 20 user feedback LEDs replicate LED output on RC car • Front will be denoted with a print of a black & white top-view sketch of a car • 5”x6” capacitive touch area is uncovered PCB • External 2” antenna for RF transmission to RC car

  11. Packaging Design - LED Output Vehicle • 32”x12”x10” • 12 LEDs for front/back • 23 LEDs for sides • =>70 tricolor LEDs • ~1LED per 1.5” • LEDs mounted on 5 apiece on 14 PCBs • LED Panel PCBs mounted on inside of car’s exterior plastic • Holes will need to be drilled through car’s exterior for LEDs to show through • LEDs will extend ~3/4” off PCB, so will be able to flex and fit through

  12. Schematic/Theory of Operation • Capacitive sensor is a pair of plates/electrodes • There is also capacitance between finger and electrodes • A sensor detects change in capacitance when finger is present

  13. Schematic/Theory of Operation • Capacitive buttons are on one side of the board • The microcontroller (PSoC) is on the other side • A plastic/glass overlay (1-5mm thick) covers buttons

  14. Schematic/Theory of Operation • The capacitive sensing microcontroller is the PSoC • Each PSoC can scan buttons and communicate over I2C • Our PSoC will communicate with a DSP to process inputs

  15. Schematic/Theory of Operation • Flow of input to output: • CapSense microcontroller (PSoC) reads input from buttons – 9 PSoCs to sense 270 buttons total • DSP (dsPIC) reads PSoCs to interpret input, sends commands to LED controller wirelessly • LED controller (PIC18) coordinates LED drivers (TLCs) to produce output patterns

  16. Multi-Touch Power Supply 5V out to PSoC Linear regulators 3.3V out to dsPIC 12V in

  17. LED Output Power Supply LED Output Power Supply 12V Pb-acid battery input 5V output to PIC18, TLCs

  18. CY8 PSoC Cell Capacitive buttons CY8 PSoC I2C header to dsPIC I2C header to programmer

  19. dsPIC Core RST to PSoCs dsPIC I2C to PSoCs and TLC RF Tx to PIC18

  20. PIC18 Core Accelerometer header PIC18 RF Rx UART I2C to TLCs

  21. TLC Cell Address for I2C slave I2C to PIC18 TLC Tricolor LEDs

  22. PCB Layout – MultiTouch Board Main Components 1 Cypress PSOC chip and 30 CapSense Pads Other Components 34 Resistors, 2 Headers, 1 Capacitor, and 1 OR gate 5” x 6” Section of the larger User Interface Board Via on each CapSense pad made routing very difficult

  23. PCB Layout – MultiTouch Board

  24. PCB Layout – dsPic Board Main Components dsPIC, RF Transmitter, Power Supply Other Components 10 Capacitors, 16 Resistors, 1 Switch, and 17 Headers 2” x 7” section of the larger User Interface Board Lots of space allowed for large heat sink and ease of routing

  25. PCB Layout – dsPic Board

  26. PCB Layout – PIC18 Board Main Components PIC18, RF Receiver, Power Supply Other Components Switch, 18 Headers, 3 Resistors, 4 Capacitors, 1 Inductor, and 1 Diode 1.4” x 5” Plenty of space allowed for easy routing and the ability to actually minimize the area of the board

  27. PCB Layout – PIC18 Board

  28. PCB Layout – TLC Board • Main Components • 5 LEDs and a single TLC driver chip • Other Components • 5 Resistors, 5 Headers, 1 Capacitor • 0.5” x 5” • Tight space required careful routing

  29. PCB Layout – TLC Board

  30. Software Design/Development Status • Read inputs as 0’s and 1’s • Number of fingers = number of connected 1’s • Direction of fingers based on average coordinates of fingers

  31. Software Design/Development Status • PIC18F(LED Output Controller) • LED Output Coordination • I2C interface to 14 LED driver chips • dsPIC33F(Multiple Touch Processor) • Finger Count Detection • Area vs. discrete contacts • Direction Vector Calculation • Track angle of finger swipe • CY8C(CapSense Controller) • Activation of CapSense block, record data, then communication of data over I2C

  32. Project Completion Timeline

  33. Questions / Discussion

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