For a project in college I used an Arduino to emulate the joystick controls for an autonomous robot. The joystick was opened up and leads were attached to the 0-5V for forward/back and left/right.

Forward/Back 0.1=Backwards 100% 2.5V=Neutral 5V=Forward 100%

Left/Right 0.1=Left 100% 2.5V=Neutral 5V=Right 100%

Obviously the direction of the wheelchair was controlled by varying the voltage to the joystick. This is definitely the way to go because it still allowed the joystick to be used when the robot was not driving around under autonomous

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Graduated from school for two years now I decided I wanted to continue working on a similar project. So i bought a EZ-B, invacare wheel chair and plan on hacking into the joystick to gain control of the robot. I have been reading that i can use the PWM output to control the wheel chair. First thing I need to do is see what the voltage range is an how the robot is controlled by the joystick (hopefully it is the same or similar to the first time i did this).

When using a wheelchair hacking the joystick is the way to go. found it more difficult to control the motors directly just because they are 4 pole and have a bunch of safety features that you will have to avoid.

I am currently working on getting a 0-5V output where 0= backward, 2.5= no motion, and 5V= forward. Am i correct in saying that using the PWM is the best way to do this? The PWM control window in EZ-B controls the duty cycle which can be related to the output voltage but i do not know if this is the most efficient way of doing this.

wheelchair aside...I am essentially looking for a voltage output which can vary between 0-5v which could be used to control anything from dimming and led to controlling a motor controller.

I played with the joystick input method for some time and finally after many frustrating attempts i just bought a SabreTooth 2x60 and my troubles were over.

The chair i'm using is a Jazzy 1122 with 2 - 24 volt motors, i removed the electronic brakes which is simple and the Sabretooth can use PWM , RC and serial inputs to control the motors.

You can make the joy control work but if your center voltage is off even the tiniest bit the chair either wont start or if initialized will drift ever so lightly and it is vary difficult to maintain the pure regulated voltage that the controller requires.

I have accomplished the task with not so satisfying results, weeks even months of fiddling around with it plus various regulator boards, but in one day I had it going with the SabreTooth.

Save yourself a headache and decide if you want a robot or a wheelchair.

Putt Putt; I went through the same thing that you did. I have the "Pride Jet 3." If there is any fluctuation in the center voltage, it shuts down and flashes an error code until it is shut off and reset. I suspect that the older ones were easier to hack into, but like everything, the more advanced they get, the harder it is to modify them.

Thanks I will order a sabretooth I don't need the head ache,this really helped!

Hello All. I'm new to the forum. I have a Jazzy GT power chair. I wanted to hack the joystick but, its proving to be somewhat of a chanllange. I wanted to replace the controller with a Vantec or Saber, but then the two motors have four wires. I know that the black and red wires are for battery, but I don't know what the other two wires are. My question is two-fold....Can I just use those motors with just the red/black? And....What are the other two wires for?

Thanks (in advance), nmsr1196

Yes, you use just the Red & Black wires. The two white wires go to the motor brake. If the motor does not have 12 to 24 volts applied to it then the brake stays on and will not allow the motor to turn. You can just remove the brake, plenty of places on the web that tells you how to do it. Good luck with your project.

@Herr Thanks for the response. Do the two wires connect together then connect to the brake connection on the controller? In other words one electrical point? Thanks (in advance)