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A Question About Hacking A Wheel Chair

Has anyone ever hacked a wheel chair controller? it seems like it would make sense or is it better to use a bridge can anyone shed some lite on this ? 2 10 watt 24 vdc motors

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Synthiam
#4  
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.
#5  
Thanks I will order a sabretooth I don't need the head ache,this really helped!
#6  
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
#7  
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.
#8  
@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)
#9  
i just viewed the video(s)...question(s) answered.
thanks.
#10  
I am seeing this same problem with trying to hack the joystick directly, I keep getting error readouts for anything other than neutral position 2.44V and 2.45V respectively. Two of the left bar lights stay on and then the next 5 flash about once every .5 seconds. Has anyone figured out how to work around this? Only thing I could think of was to let the wheelchair start up with the original joystick and then introduce the second signal but I have not been having any luck... I have the Invacare storm series arrow with the mkiv A joystick. I would like to get this working with the current hardware and to not have to purchase a sabertooth.

Thanks!
#11  
One ingenious fellow in Ireland just used servos to manually move the joystick and says it works quite well. Here is the link
Linky
#12  
I have forgone trying to hack the joystick. I wasn't exactly sure to substitute.
I removed the brakes clipped the wires put a connector on the brake wires on the brakes and motors.
Since I wanted to keep the charger, I connect the brakes to the connectors and charge.
I used the roboteq motor controller to make autonomous.
#13  
@bjf5051

Lots of us here have tried to hack the various joysticks for wheelchairs and we know what is required but in the end result, thou you can hack the sticks, it is actually cheaper to buy the Sabre-tooth H-Bridge than it is to properly interface the joystick with other electronics.

I spent hours days and weeks trying to interface the sticks without buying some good quality electronics and had some success but it was always glichy and i didn't want to take the chance that my 12 mph , 250 lb robot would just blastoff when ever it wanted too or not move at all!

I bought the Sabre-tooth H-Bridge and with-in 15 minutes had a working bot with a wheel chair base under full control.

But hey, go for it and hack that stick and when you get it perfect let the rest of us dummies know how you did it.

The controllers are very high tech I even bought a programming cable for them, that alone was only $100.00 and a myriad of emails just to get it! and the cable itself is an electronics piece of rocket science with built in proprietary signals. They are NOT serial of any kind that I know of.

But don't get me wrong , I'm not trying to discourage you but when do you want to have a working bot?

:)
#14  
Yea i am finding only a few people who have been successful with hacking the joystick, mainly due to the safety aspect the wheel chair has during start up. I have been able to replicate the 2.47V and 2.50 start up on my wheel chair with no error codes on an arduino uno (no on my ez bee :/ ) so now i am on to trying to make it move which has proven difficult so far.

I have heard everyone just ends up buying the sabertooth to control it....i like the breaking feature and i really like not having to spend the extra money on it so ill prob grab an o scope and put in a few more hours.

And for the servo idea to control the joystick, extremly dangerous especially with a robot of this weight. Even with smoothing servos can be wild.

I'll keep everyone updated, let me know if you have any ideas!
#15  
@bj5051
What type of motor controller are you using?
#16  
None, I'm emulating the joystick with an arduino and two xbees using direct io
#17  
nicccceee. that sounds challenging.
#18  
@bjf5051

Send me a email, I have something that might help you a little.

Old-FireFighter138(@)neo(dot)rr(dot)com
#19  
Got it working whoo! Made an rc circuit to filter the pwm signal and connecting the wires to the joystick during the startup. I have the chair rolling forward, backward, and turning when connected directly to an arduino, not able to do this with ez board yet. Should I keep updating this forum since i am migrating twords using arduino for my project.
#20  
That's cool!
How did you do it?
#21  
I'm thinking that whatever you're doing with the arduino should be able to be done using the EZ-B. Keep posting on this thread so we all learn what you are doing and then try and replicate it.