Transcript System Overview

Run-To-Form Trainer
Phillip Park, Rishi Neeranjun, Nikhil Mehta
ECE445 Senior Design Project - Project 29
December 8, 2014
Overview
 Purpose
– Provide a wearable device that keeps track of which area
of the foot the user lands on, pronation, and pace
 Features
– Bluetooth connectivity through users phone
– Real Time pace feedback
Background Information
System Overview
 Hardware:
– Power Supply, Boost Converter
– Sensor Network
– Microcontroller Unit
– Bluetooth Module
– iPhone
 Software:
– Arduino IDE for Microcontroller
– iPhone IOS application
System Overview – Block Diagram
RTF Overview
RTF Overview
Power Supply (Initial Design)
 2 Coin Cell battery (250mAh,
6V)
– Lower max current draw
• 15mA
 Low-Dropout voltage
regulator
– L7805CV 5V output
– Linear Regulator 83.3%
efficient
Power Supply (Final Design)
 3.7V Lithium Polymer Battery 500mAh
– Max Current Draw much larger
• 500mA
– Rechargeable
 Boost Converter
– TPS61090 5V output
– Power Converter 95%
efficiency
Power Supply Waveform
Power Budget
BatteryCapacity(mAh)
= BatteryLife(h)
CurrentDraw(mA)
Battery Capacity
Current Draw
Battery Life
500mAh
34.3mA
14.3Hours
Sensor Network
 VibraTab from Parralax
– Responds to force, flex, shock,
vibrations
– Settling time 150ms
 1MOhm resistor for sensitivity
 5.6V Zener diode to cap
voltage
Sensor Network Waveform
Microcontroller Unit
 Atmega328p from Atmel with
Arduino Optiboot Bootloader
– 5V operating voltage
– 20MHz clock cycle
 Arduino IDE
– Reads signal inputs and sends results to
iPhone via Bluetooth
 Controls Diagnostics(LEDs)
Microcontroller Flow Chart
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Blue = Bluetooth
Sky Blue = User
Red/Green = LED/Diagnostics
Grey = Data processing
Yellow = Data transaction via Bluetooth
Microcontroller Unit Challenges
 Distorts data when sent to iPhone
– Too much data sent at a time
• Format results into array of strings, and process through a ForLoop.
Diagnostics
 Red LED- Bluetooth
– Blinks if Bluetooth is advertising
signal
– Solid if Bluetooth is connected to
a device
 Green LED- RTF
– Solid if running session is in
progress. Data is being recorded.
Bluetooth Module (Initial Design)
 RN-42XV from Rover Networks
 Bluetooth 2.1 + EDR
– Outdated technology
 3.3V operating voltage
– Logic Level mismatch
 Not MFI (Made For i(product))
– Incapable for developing an IOS app
Bluetooth Module (Final Design)
 nRF8001 Nordic Semiconductor
 Bluetooth 4.0 (BLE)
– Lower power consumption
– More Reliable
– Marketed for devices like the RTF
 Provided Arduino library
 Doesn’t need MFI Licensing
– Uses Apple’s “CoreBluetooth” framework
iPhone Application - CoreBluetooth
iPhone Application - CoreBluetooth
 Uses custom Service and Characteristics provided
by Nordic Semiconductor
– Service: UART
– Characteristics:
» RX
» TX
 Serial-like data communication between
microcontroller and iPhone
iPhone Application - Screenshot
Future Work / Opportunities
 Full integration within shoe
– Collaboration with Nike, Adidas, Under Armor
• Nike + iPod
 Physical therapy
– Wet foot test substitute
 Improve UI
– Take advantage of smartphone features
• GPS
• Audio
 Expand Accessibility
– Android App
Ethics
 Consult a physical therapist before using the RTF
– Results from the RTF are not medically verified at this
time
 Sending small voltage signals in close contact to
user’s foot
– User must be fully protected from any risk of shock.
Acknowledgement
 TA: Cara Yang
 Prof. Jonathan Makela
 Prof. Michael Oelze
Thank You!
 Questions?