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

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

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

System Overview User Interface User Interface Warning Stage Warning Stage Prevention Stage Prevention Stage Transmission Stage Transmission Stage

Team Dynamic

Research Background Research Background Two-Point Gait Three-Point Gait Two-Point Gait Three-Point Gait

Research Background Research Background Four-Point Gait

Research Background - Free Body Diagram

System Inputs/Outputs System Inputs/Outputs

Friction Sensor

Activation Switch

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

Experiment Results

Warning Activation Motion Sensor Motion Sensor Friction Sensor Friction Sensor

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

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

Activation Algorithm

Prevention mechanism Prevention mechanism

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

Hardware Design 1. What are on the Board? 2. Detailed hardware description for certain parts on the board 3. RF remote alarm system

What are on the board? 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

What are on the board? What are on the board? 2 lines x 16 character LCD - Display the user response

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

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

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

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

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

The built PCB image

Detailed hardware description

Detailed hardware description Detailed hardware description

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

RF alarm system Detailed Schematic

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

Software Design

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

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

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

Software - Testing Crutch 1 – Cemented Floor

Software - Testing Crutch 2 – Cemented Floor

Software - Testing Crutch 1 – Carpeted Floor Crutch 1 – Carpeted Floor

Software - Testing Crutch 2 – Carpeted Floor Crutch 2 – Carpeted Floor

Software – Testing Crutch 1 – water/slippery Crutch 1 – water/slippery

Software - testing Crutch 2 – water/slippery Crutch 2 – water/slippery

Timeline

Finances Description Total Prize 2 lines* 16 LCD module $ $ Circuit components $ $ MHz RF transmitter/receiver $ 8.00 $ Battery, Battery Charger $ $ Triple Axis Accelerometer $ - $ - Microcontroller $ $ DC Motor $ $ Atmel Microcontroller development board $ $ Underarm Crutch $ $ Mechanical components $ $ Total Cost $ $

Finances Additional Costs spare/extra parts spare/extra parts travel travel tools/equipment tools/equipment PersonSpent Amir $ $ James Stan $ $ Ben $ $ Kyle $- $- $- $- Total Expenditure $ $

Business Opportunity Hospital: The patient with temporary or permanent disability with their lower body Hospital: The patient with temporary or permanent disability with their lower body Senior’s home: The senior people who has difficulty walking or weak vision. Senior’s home: The senior people who has difficulty walking or weak vision. Home: For family member with disability Home: For family member with disability

Future Work Sensors Sensors Hardware Hardware Software Software Prevention Prevention Summary Summary

Future Sensors Bearing System for Suspended Friction Sensor Bearing System for Suspended Friction Sensor Optical Motion Slip Sensor Optical Motion Slip Sensor Water Sensor Water Sensor

Future Hardware Reduce Space Reduce Space Less AmplifiersLess Amplifiers Surface MountSurface Mount Smaller BatterySmaller Battery Reduce Cost Reduce Cost New MCNew MC Machine ManufacturingMachine Manufacturing Smaller BatterySmaller Battery

Future Software Communication between crutches and nurse Communication between crutches and nurse Communication between left and right crutches Communication between left and right crutches New Interface New Interface GUI GUI

Future Fall Prevention Larger Range of Fall Prevention Larger Range of Fall Prevention Closed Body Closed Body Water ResistantWater Resistant No Catching of ClothingNo Catching of Clothing Lighter Lighter Less Stress on BodyLess Stress on Body Adaptable/ Reusable Adaptable/ Reusable Connect to different crutch stylesConnect to different crutch styles

Summary Conceal to 1 ½ “ Diameter Conceal to 1 ½ “ Diameter Reusable Reusable Surface-mount Electronic Components, and reduce cost Surface-mount Electronic Components, and reduce cost

What We Learned Out of the box thinking Out of the box thinking Cooperative teamwork is an absolute necessity Cooperative teamwork is an absolute necessity Resourcefulness Resourcefulness How to work in stressful situations How to work in stressful situations How to fill the gap between theory and practice How to fill the gap between theory and practice

Acknowledgement ASA Concepts would like to thank: Patrick Leung Steve Whitmore Dr. Andrew Rawicz Fred Heep Jason Lee Jamie Westell

Questions?