1. ECE 445 Electronic Shoe Sizing Device Group 43: Robert McDonald, Eric Ayala, Siyan Guo May 3 rd, 2016

2. Introduction: About our Project Goal: Design an automated foot sizing device to get more accurate and consistent results than the Brannock device (standard device used in shoe stores)

3. Electronic Shoe Sizing Device

4. Objectives  Obtain accurate foot measurements  Create a simple user interface for customer to control the device  Safety features will be implemented

5. Block Diagram

6. Micro-Controller  16 Analog Inputs  54 Digital Inputs among which 15 can be used as PWM Inputs Arduino Mega 2560

7. Force Sensors  5 force sensors adhere to padding on the walls to halt wall movement 2 square sensors for length walls 2 circular for ball of foot object 1 strip sensor for width wall FSR 406 FSR 400 FSR 408

8. Distance Sensors  3 distance sensors embedded to the walls  Accuracy within 3 mm error at a range of 8 cm to 40 cm HC-SR04

9. Sensors and Limit Switches Length Force SensorLimit SwitchesWidth Force Sensor

10. Sensor Data Distance sensor data Force sensor data for 20 g weight

11. Initial Mechanical Design

12. Final Mechanical Design

13. Motor Controller  Motor Operations:  Starting and stopping the DC motor  Selecting forward and reverse operation  Regulating speed  Protection against faults that include overlap (shoot through)

14. Motor Controller Schematic

15. Final PCB Boards

16. Motors  Utilizes (4) 12 V DC gear motors  Uses PWM for speed control  Average wait time around 10 seconds  Approximately 5 A stall current

17. Motor RPM Calculation  Get RPM for 10 second wait time  Average foot length: 22 cm, 40 cm - 22 cm = 18 cm  (18 cm)/(10 s) = 1.8 cm/s speed of wall  Screw spacing on lead screw is about 3 mm  (1.8 cm/s) / (.3 cm/rotation)=6 RPS =360 RPM

18. Comparison of Torque Original motors: Final motors:

19. Choice of Motors Lynxmotion PGHM-01: ●Less than 5 A stall current ●1120 g-cm nominal torque ●300 RPM with no load

20. Wi-Fi Module  Access Point  3.3 V  115200 baud rate  Accept command in Serial interface ESP8266

21. Software  Data Collection  Data Analysis  Display

22. Data Collection  PuTTY terminal for user input  MCU gather sensor data

23. Data Analysis

24. Display  PuTTY terminal on Cellphone

25. Conclusion and Further Work  Fail to integrate as a whole  Arduino input buffer not being cleared - caused unexpected movement  Future work - get around input buffer  Future work - modify walls and modify padding  Future work – create app

26. Thank you to: Professor Jonathan Makela Mr. Dave Switzer (Machine Shop) TA: Benjamin Eng Zitao Liao Jackson Lenz Braedon Salz

27. Citations  "WiFi Module - ESP8266." - WRL-13678. N.p., n.d. Web. 02 May 2016.  "12VDC, 300rpm Planetary Gear Motor PGHM-01." Robotshop. N.p., n.d. Web. 2 May 2016.  "Interlink Electronics." Interlink Electronics. N.p., n.d. Web. 02 May 2016.  "HC-SR04 Datasheet." HC-SR04 Datasheet. Elec Freaks, n.d. Web. 02 May 2016.

28. Thank You!