1. Read an analog 2-axis joystick with the Arduino analog input ports. The magnitude and direction of the X-axis input of the joystick should output a differential PWM output to the left and right DC motor H-Bridge amplifiers which is applied to the PWM duty-cycle worked out in point 2 below.
2. The Y-axis input of the joystick should control the duty-cycle of the PWM, i.e. the speed of the wheelchair.
3. There should be an Emergency Stop switch, easily accessible by the user of the wheelchair.
4 Steering will be effected by using caster wheels in front and differential drive to left and right motors ( Point 1 above)
5. You may also want to examine raising and lowering the chair with an up/down selector, to empower the wheelchair user in raising him/her to the height of upright bipedal people.
Before you actually allow a differently abled person to use the wheelchair, you will need to examine safety features like over-riding the system if it begins to misbehave due to faulty input from the joystick. Please ensure you use a WDT (watch dog timer) system to check that your processor has not locked up with a certain output.
1. Read an analog 2-axis joystick with the Arduino analog input ports. The magnitude and direction of the X-axis input of the joystick should output a differential PWM output to the left and right DC motor H-Bridge amplifiers which is applied to the PWM duty-cycle worked out in point 2 below.
2. The Y-axis input of the joystick should control the duty-cycle of the PWM, i.e. the speed of the wheelchair.
3. There should be an Emergency Stop switch, easily accessible by the user of the wheelchair.
4 Steering will be effected by using caster wheels in front and differential drive to left and right motors ( Point 1 above)
5. You may also want to examine raising and lowering the chair with an up/down selector, to empower the wheelchair user in raising him/her to the height of upright bipedal people.
Before you actually allow a differently abled person to use the wheelchair, you will need to examine safety features like over-riding the system if it begins to misbehave due to faulty input from the joystick. Please ensure you use a WDT (watch dog timer) system to check that your processor has not locked up with a certain output.
