The joystick board for the powered wheelchair Jean-Marc Capron ISEN September 30 th 2011 University of Kent 1 Part-financed by the European Regional Development Fund

b joystick  C ATMEL ATmega328 ADC 10 bits quad DAC I2C to original system  C ATMEL ATmega2560 (ARDUINO or anything else) SPI UARTUSB PC sensor 1 sensor 2 sensor n joystick module sensors module

b joystick  C ATMEL ATmega328 ADC 10 bits quad DAC I2C to original system SPI joystick module  C ATMEL ATmega2560 SPI UARTUSB PC sensor 1 sensor 2 sensor n sensors module actual joystick’s position modified joystick’s position

joystick module mounted in the original system

b joystick  C ATMEL ATmega328 ADC 10 bits quad DAC I2C to original system SPI joystick module  C ATMEL ATmega2560 SPI UARTUSB PC sensor 1 sensor 2 sensor n sensors module LED visual interface SPI optocouplers

Sensors used on the prototype: Ultrasound sensors 9 implemented (only 4 active at one time) Advantages:- cheap solution - long range (typ. 20 cm  5 m) Drawbacks:- long response time (up to 50 ms) Infrared sensors 2 implemented (when passing through a door) Advantages:- no latency induced Drawbacks:- short range (< 1 m)

details (top view) 59 mm 36 mm 23 mm microcontroler

details (bottom view) quad digital-to-analog converter connection to joystick connection to sensors module connection to original system

Part-financed by the European Regional Development Fund Plan of presentation I. Outline of the task within the context of the project II. Main results III. Future challenges and the work to be done 9