Shoe for the Elderly and Handicapped

1. Shoe for the Elderly and Handicapped A Senior Design by #7 Stephanie Chou, Seung Won Min And Shawn Winston

2. Introduction 710 million people worldwide live with a condition limiting basic physical activities. The elderly and handicapped have difficulty bending over to put on their shoes

3. Overview • Shoe Features: • Remote controlled open and closes heel of shoe • Inductive charging • Provides feedback to increase user’s foot circulation • Safety features

4. Power Supply 5V Recharge Module Project Block Diagram 9V Arduino Bluetooth Remote Control 9V Data sent/ data received Heel Module Safety Module Circulation Detection Module

5. Project Build and Design

6. Power Supply • Requirements • Battery supplies 3.7V to boost converter • Boost converter amplifies voltage to 9V for rest of circuit to run on

7. Power Supply Testing • Verification • Measure output of boost converter with 3.7V input • Verified that all components worked together at the same time when battery was connected

8. Voltage Step Up Calculation Peak- to- Peak Ripple 0.19/5.044= 3.766% min(Voutput) ≥4.5V Output Input

9. Power Supply Calculations • Charging Time • 5 hours from empty to full • Battery Lifetime • Battery Capacity: 500 mAh • Circuit current draw at full usage: 590mA • Idle current draw: 140mA • Average battery life: 3 hours

10. Power Supply Challenges • First boost converter initially failed

11. Heel Module • Requirements • Motor turns on and off when given the open or close signal from the remote control module • Motor locks and stays in place when no power is received.

12. Heel Module - Schematic

13. Heel Module • Linear Actuator Motor • PCB and battery housed in the heel of the shoe

14. Heel Module Testing • Verification • Send open and close signals from Arduino pin and observe if motor opens fully and closes fully • Ensure motor has enough torque to move heel • All verifications passed

15. Heel Module Challenges • Determining what type of motor to use • Mechanical Design

16. Charging Module • Requirements • AC/DC converter outputs 12V • Lithium-ion battery charges though USB charger • Transmitter from wall outlet inductively couples with inductive coil receiver

17. Charging Module • AC/DC converter, Transmitter, Receiver, USB charging regulator, Rechargeable Lithium-ion Battery

18. Charging Module Testing • Verification • AC/DC converter outputs 12V • LED on Receiver lights up when it receives voltage from Transmitter • Voltage on battery changes as charge increases

19. Charging Module Challenges • Chip on transmitter fried day before demo • May have been caused by plugging leads into adapter backwards • No datasheet for inductive chargers

20. Remote Module • Requirements • Open and close shoe when open and close button is pressed on the smartphone • Vibrates phone when circulation motion unit sends a no movement signal.

21. Remote Module • Android and Arduino communicate via Bluetooth. • User controls opening and closing of shoe from application

22. Remote Module - Android • Requirements • Send signal via Bluetooth to control opening and closing of shoe • Receive signal via Bluetooth to vibrate when user doesn’t move for set amount of time

23. Remote Module - Arduino • Requirements • Send signal to Android when accelerometer detects zero motion • Send signal to Android when accelerometer detects renewed motion • Receive signal from Android to open and close motor

24. Remote Module Testing • Verification • Determined the data type of signal being sent and received by android • Determined the data type of signal being sent and received by Arduino • Tested using Blueterm App • Ran the App

25. Remote Module - Challenges • Assuring reliable Bluetooth connection • Determining datatype of signals sent between android and arduino • Android programming

26. Safety Module • Requirements • Measures the temperature of the battery and sends a “danger” signal to cut of power supply if battery is over 90°C.

27. Safety Module – Schematic

28. Safety Module • Thermistor detects change in resistance due to temperature change • Power to circuit is cut when temperature threshold is reached • Temperature Threshold: 90°C • Testing Threshold: 40°C

29. Safety Module Testing • Verification • Used a temperature variable soldering iron to heat thermistor • When thermistor detects temperature threshold, try to open and close the motor • The motor should not open or close. • No signals should be sent to Android from safety module

30. Safety Module Simulation

31. Safety Module Challenges • Testing couldn’t exactly replicate real life situation • Delay in temperature reading • Lowered temperature threshold to compensate

32. Circulation Module • Requirements • After 30 minutes of inactivity, the phone vibrates constantly until the user moves • Inactivity: the accelerometer detects no change in movement • Research showed that 30 minutes of inactivity results in measurable decrease in foot circulation • The phone vibrates every second until the user moves

33. Circulation Module Testing • Without Android: connect Arduino to PC and read output data • With Android: wait for vibration signal • Shake the shoe to make the vibration stop

34. Circulation Module Challenge • Changed original vibration design • Replaced vibration motor with phone vibration • It is hard to feel vibrations in the feet

35. Final Circuit Design

36. Conclusion

37. Successes • The main functionality of the shoe works • Bluetooth and Android interaction • Features behave as expected

38. Challenges • Reliability vs cost/practicality • Mechanical Design • Motor • Wireless charging • Piezoelectric vs. Inductive Charging • Wireless Connectivity

39. Future Work • User testing needs to be completed • Practicality of product needs to be finessed • Charging module needs to last longer and charge faster • Industrial Design • Fashion Design • Application UI Design

40. Thank you! • Service Shop • Machine Shop • Rishi • Prof Lilly