1. Wheelchair Navigation Aid
Technical Content Review
By Rob Riel

2. Overview Planned Workflow Top Level System Design Hardware Design
Software Design
Mechanical Design

3. Planned Workflow
Design hardware devboard, use for testing, work out any gremlins
Re-spin devboard once for connectors for final product
Develop Software after dev board obtained
Software Design
Hardware Design
Final Re-spin
Debug Hardware

4. Top Level System Design
System processes data from range finding sensors
User is alerted visually and via sound of object encroachment.
Product contains LCD screen which displays useful information
Product also lights path of wheelchair with high power LED lighting

5. Top Level Design cont.

6. Hardware Design Hardware incorporates proven design practices such as:
UART-> FTDI -> USB
Total board breakout connectors for access to all pins. (great for debugging and development)
Stable 8Mhz operation
Over engineered power traces to prevent burnouts
Onboard Temp monitoring

7. Hardware Design cont.

8. Hardware Layout

9. Rendered Product Electronics

10. Software Design Software incorporates maximum efficiency by using:
ISRs whenever possible
Lightweight LCD drivers designed in house
DSP instructions which take 1 clk vs normal 4 clks.
Because drivers are designed in house complete control is maintained over data flow, decreasing time to market due to debugging

11. Structure Definitions
Overall Code Diagram
Variable
And
Structure Definitions
System
And
Peripheral
Setup
Run Time Routines
and
Data
Processing

12. Variable and Structures
Define Constants
Define Sensor Struct
Define Macros For Screen
Define Screen
Struct
Define Loop Vars
Define UART
Struct

13. System and Peripheral Setup
Setup Oscillator
Setup ADC Regs
Setup Watchdog
Setup Interrupts
Setup Pin State (TRIS)
Setup UART Init Regs
Set Initial Pin Output
Initialize Screen

14. Run Time Routines & Data Processing
Fetch & Store Sensor Data
ISR For Change Mode
Compare Sensor Data to Thresholds
Update State Machine, Store to Screen Structure
Calculate Bat Remaining
ISR For Sending Data Via UART
Update Screen

15. Mechanical Design Control Box

16. Mech Design LCD Box