1. ECE 477 Design Review Group 9  Spring 2005 Omar Shaikh - Nathan Smith - Jeff Huston - Ryan Koors

2. Presentation Outline G.I.M.P. overview Project-specific success criteria System block diagram Component selection rationale Packaging design Schematic and theory of operation Preliminary PCB layout Software design/development status Project completion timeline Questions / discussion

3. Project Overview General Informative Medical Prosthetic Integrable gait feedback system for existing lower limb prosthetic devices. Integrable gait feedback system for existing lower limb prosthetic devices.

4. Project-Specific Success Criteria 1. …detect pressure changes in the shoe via an ATD port on a microcontroller and to map those pressure differentials to distinct vibrating patterns in a vibrating motor strap. The ability to… i

5. Success Criteria continued… 2. … execute sequential vibrating patterns, thus providing “how-to-walk” training capabilities The ability to… Human leg of cross- section

6. Success Criteria continued… 3. … record sensor data and upload to a computer via Ethernet connectivity The ability to… Data uploading

7. Success Criteria continued… 4. display system status (mode, battery level) on an LCD The ability to… MODE : Warning: Low Battery LEARNING: Walking Calibration

8. Success Criteria continued… 5. … automatically determine when the prosthetic is idle and enter into a power-conservation mode in which certain functions/ports will be turned off (some ATD, LCD, etc). The ability to… Note: Does not reflect actual battery life

9. Block Diagram Microcontroller Amplifier Circuit Shielded cable LCD ATD PORT RESET Reset Button PORT RPG Ethernet device Network Applications (calib. and data upload) Power Supply: 7.2Vdc RC car battery DC Switching Regulator Power supply +/- 5Vdc reg.3.3 Vdc reg. BJT amps. Vibrating motors LEDs Pressure Sensors = on PCB = off PCB = plug connection required KEY Clinometer Fused 7.2 supply

10. Component Selection Rationale FLEXIFORCE SENSORS: Clinometer: RationaleMain Components: Relatively inexpensive Flat and flexible Tried and true in previous senior design projects Easily-readable, non- discrete output Met durability requirements

11. Component Selection Continued… Vibrating motors: HC12 NE64 Variant Microcontroller: RationaleMain Components: Low current requirements Very inexpensive ($1.25 each) Flat shape for implementation Met I/O requirements (80) Integrated TCP/IP functionality 64K Flash memory

12. Component Selection Continued… DescriptionVendorPart NumberUnit CostQuantityTotal Cost FLEXIFORCE SENSORSTekscanA201-100$13.754$55.00 SENSOR CLINOMETER HORIZONTL FLNGAccuStar02110102-000$139.001 VIBRATING MOTORSSanko Electric1E120$1.2510$12.50 MC9S12NE64V1 freescale semiconductorMC9S12NE64CPV$0.001 Total (approximate): $600

13. Packaging Design Battery PCB RPG LCD Peripheral Connections 4 in. 7 in. 1.5 in.

14. Schematic/Theory of Operation Power Supply and Distribution: Regulator circuits from regulator manufacturer website 5V -5V 3.3V 7.2 V unregulated

15. Schematic/Theory of Operation Microcontroller:

16. CRG module handles power regulation on reset ATD pins Motor PWMs LCD pins BDM header Run/boot switch

17. Schematic/Theory of Operation Microcontroller Headers:

18. Schematic/Theory of Operation Pressure Sensor Circuits: 4 inverting integrator Amps with noise suppression caps on output -5 V 100 K pots (R12,12,13,14)

19. Schematic/Theory of Operation Pressure Sensor Circuits: 10 Class D amplifiers, all R values chosen so “ON” is always in saturation

20. Schematic/Theory of Operation Connectors, etc.:

21. Preliminary PCB Layout Trial 1: Size: 5” X 3” COMPLETE FAILURE

22. Preliminary PCB Layout Trial 2: Size: 7” X 4” (100% routed, 0 DRC errors) Only common GND between A&D Analog Amp. Circuits Digital Circuits Power Supply ATD Amp. Circuits

23. Software Design/Development Status Pre-Module Development Status Pulse Width Modulator (PWM) Pulse Width Modulator (PWM) Analog-To-Digital (ATD) Analog-To-Digital (ATD) Hardware Interrupts Hardware Interrupts Memory Management Memory Management Ethernet Connectivity Ethernet Connectivity Module Development Status Liquid Crystal Display (LCD) Liquid Crystal Display (LCD) Sensor Data Management (SDM) Sensor Data Management (SDM) Pressure and Clinometer Sensor Inputs Pressure and Clinometer Sensor Inputs Motor Outputs Motor Outputs Power Down Mode – Battery Monitor Power Down Mode – Battery Monitor Startup Mode – Watchdog Startup Mode – Watchdog

24. Project Completion Timeline Schedule through user manual composition. (April 13)

25. Questions / Discussion