1

The joystick board for the powered wheelchair

Jean-Marc CapronISEN

September 30th 2011University of Kent

Part-financed by the European Regional Development Fund

bjoystick

mCATMEL

ATmega328

ADC10 bits

quadDACI2C

tooriginalsystem

mCATMEL

ATmega2560

(ARDUINOor anything else)

SPI

SPIUARTUSBPC

sensor 1

sensor 2

sensor n

joystickmodule

sensorsmodule

bjoystick

mCATMEL

ATmega328

ADC10 bits

quadDACI2C

tooriginalsystem

SPIjoystickmodule

mCATMEL

ATmega2560

SPIUARTUSBPC

sensor 1

sensor 2

sensor nsensorsmodule

actualjoystick’sposition

modifiedjoystick’sposition

joystick module mounted inthe original system

bjoystick

mCATMEL

ATmega328

ADC10 bits

quadDACI2C

tooriginalsystem

SPIjoystickmodule

mCATMEL

ATmega2560

SPIUARTUSBPC

sensor 1

sensor 2

sensor nsensorsmodule

LEDvisual 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 m

m

23 m

m

microcontroler

details (bottom view)

quaddigital-to-analog converter

connectionto joystick

connectionto sensorsmodule

connectionto originalsystem

9Part-financed by the

European Regional Development

Fund

Plan of presentationI. Outline of the task within the context of the

projectII. Main resultsIII. Future challenges and the work to be done