1. Propulsiometer Instrumented Wheelchair Wheel Prepared by: Seri Mustaza (BME) Siti Nor Wahida Fauzi (BME) Ahmad Shahir Ismail (EECE) Hafizul Anwar Raduan (CompE) Advisor: Dr. W Mark Richter (PhD, Director of Research and Development, MAXmobility)

2. MAXmobility Accessible wheelchair treadmill Basically, working with ergonomic wheelchair:  Propulsiometer instrumented wheelchair wheel  Transfer friendly wheelchair  Variable Compliance Hand-Rim Prototype (VCHP)  Effective ways to propel the wheel

3. Propulsiometer To access the load applied by manual wheelchair user. Consist of DAQ, load cell, wireless transmitter, battery, DC/DC converter, sensor. Located on tubular hoop that can be mounted on different sizes of wheelchair’s wheel. Mainly use as research tool in lab. Ex: Calculating metabolic rate

4. Propulsiometer

5. Viasat MiniDAT™ Battery Sensor Load Cell DC/DC Converter

6. Data Collected Angle vs. time Torque vs. time  Tx  Ty  Tz Force vs. time:  Fx  Fy  Fz

7. Data collected from propulsiometer to the PC Force, Torque, & Wheel Angle

8. Load Cell signals Each of the 6 signals ranges from -5 V to +5 V 12 bit A/D converter Resolution = range/# of states (10/4096) For each step size, would equals to 2.4412mV.

9. MiniDAT™  16-bit resolution  16 single ended or 8 differential analog inputs  8 digital I/O lines  IEEE 802.11 wireless LAN  Uses 15V DC voltage  7.9 x 4.2 x 1.42 inches (LWH)  Weight = 1.5lb  Cost = $4,625.00

10. Problem MiniDAT is no longer available Bulky Uses too much power Cost = $4,625.00 Have to wait about 20 minutes to reboot

11. Main GOAL Replacing MiniDAT™

12. Specific Goals Size: 4 x 4 x 0.5 inches (LWH) Weight: ~0.25lb Cost: less than $1000.00 Low power consumption

13. Target Specification 7 analog channels and 1 digital channel A/D with 12 bit resolution 1 quadrature encoder input Wireless capability Sampling rate of at least 10 kHz Accepts voltage signal of -5/+5 volts Power consumption ~5 watts Small and compact

14. Circuit Diagram

15. Components (A/D converter) MAX186  8 channel single-ended  12-bit resolution  Input range: 5V  Sampling rate of 133kHz  Operates at 5V

16. Components (Multichannel RS232 Drivers/Receivers) MAX220  Chip that made it possible to connect RS232 and MAX186  Data rate =120 kbps  Operates at 5V

17. Components (5V/Programmable Voltage Regulator) MAX666  Dual mode operation: Fixed +5V or Adjustable +1.3V to +16V  Regulates the power supply to provide specific voltage to components in the circuit  Operating range +2V to +16.5V

18. Components (Quadrature Decoder) US Digital EDAC2  Converts incremental encoder into analog position sensor  12-bit analog resolution  Output range: 10V  Operates at 12V

19. Components (Wireless Serial Adapter) Socket Cordless Serial Adapter (CSA)  Uses RS232 (Serial Port)  Has a class 2 Bluetooth  Range up to 10m  Simple plug, install, and play

20. If all else fails… Current solution is the most optimum (cost, size, etc) There is slight chance that it would not work So, we formed a backup plan

21. The backup plan Consists of two pre-packaged components and one software package:  Sensoray Model 526  Airborne Embedded Wireless Bridge, Ethernet to Wireless LAN (Module)  xPC Target 2.9

22. Sensoray Model 526 PC/104 Multifunctional I/O board Four 24-bit quadrature encoder inputs Eight 16-bits analog inputs Approximately 4’’x4’’

23. Airborne Ethernet to Wireless Add wireless LAN connectivity to Model 526 IEEE 802.11b compliant Very small footprint, less than 2’’x2’’

24. xPC Target 2.9 from Mathworks Provides high-performance, host-target prototyping environment Makes it easier to program Model 526

25. Current Status Finalizing the components needed for current solution Buying the components Building the solution