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Smart Crutch The 6 th arm

Smart Crutch The 6 th arm. ENSC440 Group #5 Tues, April 14, 2009. Story Time ! Why do we want to make the Smart Crutch!!!. Once upon a time. I don't wanna slip!!!. System Overview Team Dynamics Research Background

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Smart Crutch The 6 th arm

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  1. Smart Crutch The 6th arm ENSC440 Group #5 Tues, April 14, 2009

  2. Story Time ! Why do we want to make the Smart Crutch!!!

  3. Once upon a time

  4. I don't wanna slip!!!

  5. System Overview Team Dynamics Research Background System Input/Output Friction Sensor Motion Sensor Experiment Result Prevention Mechanism Hardware Design RF Alarm System Software Timeline Finances Business Opportunities Future Work Acknowledgments Presentation Outline :

  6. System Overview • User Interface • Warning Stage • Prevention Stage • Transmission Stage

  7. Team Dynamic

  8. Research Background Two-Point Gait Three-Point Gait

  9. Research Background Four-Point Gait

  10. Research Background - Free Body Diagram

  11. System Inputs/Outputs

  12. Friction Sensor

  13. Friction Sensor

  14. Activation Switch

  15. Motion Sensor • Triple Axis Accelerometer • Output Voltage with Respect to Gravity • Output Voltage Between 1.3V-2V

  16. Experiment Results

  17. Warning Activation Motion Sensor Friction Sensor

  18. Prevention Activation Conditions to Activate Prevention: • Activation Switch is On • Happens After Warning • Decreasing Angle (10 Degrees/0.07 (v))

  19. Alarm Activation • When User Falls • Less than 30 Degrees or More than 160 Degrees in X-Axis or Y-Axis

  20. Activation Algorithm

  21. Prevention mechanism

  22. What does it do? • Arm extends outwards • Extra Support • One-way Gear prevents backsliding • Pull-back mechanism

  23. Hardware Design • What are on the Board? • Detailed hardware description for certain parts on the board • RF remote alarm system

  24. What are on the board? Atmel Atmega16A 8 bits microcontroller • 32 programmable IO pins • 16K bytes in system programming flash • We use ISP interface to program the microcontroller

  25. What are on the board? 2 lines x 16 character LCD • Display the user response

  26. What are on the board? 5 user buttons interface • For user to enter their User ID and weight

  27. What are on the board? Accelerometer ADXL330 • Used for measuring the angular position of the crutch RF transmitter (ASK scheme) • Used for sending the help message to the remote receiver during emergency situation

  28. What are on the board? Friction sensing circuitry Fall-prevention mechanism control circuitry On board Buzzer • Will sound when the user has the tendency to slip

  29. What are on the board? 5V regulator circuitry • The power source is a 8.4V Ni-Cd battery with 1800mA-hour • The total current draw for the overall system is around 200mA

  30. On/Off Switch 2X16 Characters Black/White LCD 5V regulator Power Circuitry Warning DC Buzzer 434MHz RF transmitter Power Indication LED Reset Button Friction Sensing Circuitry Microcontroller 10 Pin ISP Interface Fall Prevention Motor Circuitry Accelerometer User Interface Buttons Enter Button Control Circuitry 6 pin Motor Connector PCB layout

  31. The built PCB image

  32. Detailed hardware description

  33. Detailed hardware description

  34. RF alarm system • The remote alarm system will generate a series of beeping sound when crutches fall • Transmission range within 100m

  35. RF alarm systemDetailed Schematic

  36. Software Design Microcontroller resources • 16 bit timer – warning and alarm • 512 B EEPROM – user info database • External interrupt 0 – push buttons • 8 bit processor • 1 MHz internal clock • AREF ~ 2.56V; 2.65 used

  37. Software Design

  38. Software ADC calculation • single ended connection • Aref = 2.65 V Vin = (ADC * Aref) / 1024

  39. Software - Testing • Use 512 B eeprom for dumping sensor values • Extract values from txt file and convert to Matlab • Plot values in matlab • Plot values in pyLab • 72 kg

  40. Software - Testing Color Scheme • Green – Friction Sensor Voltage • Red – Required Angle Voltage • Blue – Y-Axis Voltage • Light Blue – X-Axis Voltage

  41. Software - Testing Crutch 1 – Cemented Floor

  42. Software - Testing Crutch 2 – Cemented Floor

  43. Software - Testing • Crutch 1 – Carpeted Floor

  44. Software - Testing • Crutch 2 – Carpeted Floor

  45. Software – Testing • Crutch 1 – water/slippery

  46. Software - testing • Crutch 2 – water/slippery

  47. Timeline

  48. Finances

  49. Finances Additional Costs • spare/extra parts • travel • tools/equipment

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