Let's Make Robots!

Remote controlled unmanned power-chair

Ok, My idea...


I have reason to need a bluetooth or r/f remote controlable powered wheelchair. To be able to remotely turn it on (& off) and manouvre it from an outdoor shelter over to a freshly parked car's drivers door.

What I have at the moment is just the base power chair:

Powertec F50 by Sunrise Medical


What I wish to do as much as is possible is to leave the current set-up as it is, and to add the propsed r/c system to work along side it.


perhaps you can help, I am not a robot builder. Assuming this project idea interests you I'll continue...

I'm not sure how much you've studied the typical design of an electric wheelchair, but on the Powertec F50 basically there's the control joystick pod (Lets call it a peripheral device) which has a wire running to the back of the machine (socket & plug) under the seat to the main controller box (brain thingy).

I guess what would be ideal is if where that lead plugs in had a 'splitter' on it so that an R/C receiver relay peripheral device could be spliced in and the original unmolested brain-controller could get the motion inputs from either input peripheral.

Not sure what you think of that but I'd want to be able to keep the original joystick pod as standard and functional as possible, once in the seat it would be used to direct the chair as normal.

What I can do is take photos of the chair and it's component parts for you for starters to have a looksie?

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Hi Jay,

Its been a long road of experimentation, trial, and a helluva a lot of error.  But, my latest revision is based on the now famous BOA Bridge (catchy aint it BOA?).

Some quick highlights of the history :

1. Ended up ripping all of the "brains" and safety controls out of the chair, because they did not agree with my plot of enslaving humankind.

2. Tried a large variety of homebrew electronic circuits to control the very hefty wheelchair motors from a digital source - put them all through a variety of tests - all went POOF in flames and mushroom clouds of silca

3. Tried a commercial (robot power) simple H bridge - POOF (that was expensive - not doing that again)

4. Talked with BOA at length about the mystries and benefits of manly MOSFETs  -  helped a little describing why a gnd on the gate is needed to turn off the MOSFET

5. BOA comes up with the BOA Bridge - a fabuloso simple electronic design

6. Robologist suggests a gate driver - turns out in my case he was right

7. So after much frustration and dead MOSFETS here is the latest revision of the controller circuit.  It has not gone through ALL of the tests, however, the ones it has gone through it has not heated up at all.  So I beleive this circuit can drive a 200 lbs heavy duty electric wheelchair without a problem - (more to come)

* the schematic is missing the IGBT gate driver


*Ugly free form circuit - I love wire nuts !

On the digital control front :

1. had computer PWM control wheelchair motors through parallel port - found this jerky an not reliaible due to task scheduling and interrupting cpu with a variety of "other tasks"
2. got a cheap DIO card from ebay - to try instead of the parallel port - card did not support pwm - or at least I could not figure out a way to do it
3. got a cheaper Arduino - hooked it up to the computer - Works Brilliantly
4. working on software for the computer & Arduino so that the Computer does heavy number crunching of video image processing from webcam and Arduino is kindof a dumb slave - but a very good dumb slave.  I think of it like the dinosaur Stegosaurus - it had two not very big brains - or like the coretex and the cerebellum - a big brain and something that is responsible for reflexes and "staying alive"
5. Setup is Computer -> Arduino -> BOA Bridge -> Wheels .  The nice thing about a regular computer it that it is extremely powerful and easy to do things we already expect.  For example wireless.  So I can do this "My Computer" --(wirless)--> Computer -> Arduino -> BOA Bridge -> Wheels.  My computer can use a keyboard or joystick or game paddle etc. so this is pretty easy "Joystick" -> "My Computer" --(wirless miles away)-> Computer -> Arduino -> BOA Bridge -> Wheels..  get my drift?

Here is some of the gui portion of the code I have been working on ....

Too much info?

Good work, glad to see you're into software as well. What program did you use for your gui? Which Arduino board?

The program is a "myrobotlab" framework.
Its a  modular service based Java application. I am developing it with eclipse, but at some point I should be able to give it away so others can "program/configure" it to their desire - using a graphics - "much like matlab" although I've never used matlab (heh)

(see the tabs in the picutre)
The individual Services running for the above example are :

Arduino Service
ParallelPort service
GUI Service
Video Service
Servo Service (2 of them)
Joystick Service

The Arduion runs Decimilia - but really there would be no reason why it could not run other Arduino varieties if I got the specs on them.  Nor for that matter any serial connected uProcessor.  When I get ready to release 0.9 version, I was hoping for donations of  different microcontrollers so I could create services for them... always more stuff ...

GroG I have been wanting to intervene a power chair at the joystick signal with a computer just as you talked about above.  I think you said you were successful after figuring out all the safety crap that accomidated with the chair.  Do you have an pictures or a link?


I am very interested-I'm into the arduino microprocessor board and I know a little programming, I also work at a power chair rehab company, lots of parts. I have been mounting servos on my joysticks for the last 3yrs and wants to try something new. I would like to get your email address if possible. 





riiidaa ,

I assume that you want this "unmanned power-chair" to move, upon remote request, WITHOUT ANYONE ABOARD, from a secure place, to a place that the disabled person could get on board, and then he/she would take direct control of the power-chair.

I also assume that you would want the disabled person to be able to get off of the power-chair, and send it back to the secure place.

In one case you'd want the power-chair to move from point "A" to point "B" upon remote request.

And then. in the other case, you'd want it to move from point "B" back to point "A".

Are my assumptions correct?

I do not know how to solve your problem.  I do NOT have the talent.

But I bet that there ARE people on this forum that DO have the talent.

Let's get this thread back on topic, O.K. guys?


Someone asked for help, and then the thread went off on tangents.  I'm not trying to be pissy, but as I see it, the thread has been hi-jacked, and the original question ( which I think is very valid ) has not been addressed.

Duane S

Wilson, NC  USA

Thanks BOA Croydon's near me :)

Hey GroG, curioius - how would yours stop in the event of a power failure, or dead battery on a slope with no 'stinking' brakes? Used to be a mobility scooter out there in the market that would just run out of juice and thenn free wheel the old deer into oblivion ;)


Oh and when you talk of yours allowing wicked fast speeds this interests me for manned use :OP 

at some point i'm going to put the electric brakes back in - but for now they were interferring with my progress of hacking the chair..

Yeah i was supprised - turns out i got an extra-heavy duty chair, and the controller circuitry kept the top end of the speed fairly low.  Its packing 2 deep cycle marine batteries.  I keep posting info as i work. 

Thanks guys for your input so far, am in London UK, and today had a chat with the chap that runs http://www.roamingrobots.co.uk which is the knock on sport based on the tv series Robot Wars. Figured as it was r/c rather than autonomous that I need it would be worth tracking down people who love using bits of old electric wheelchairs in their 'battle bot' r/c's...

Looks like he may be able to help me do the work as they offer robot building services, he says 2.4ghz bluetooth type technology will be far safer which I figured. Apparently battle bots are all moving away from, 27mhz / 40hz bands. You're right BaseOverApex safety is important, if it went runaway it could snap someone's leg like a twig or dent a car big time.

Cheers GroG, your project is very interesting, deffo want a big STOP button - and yeah I need to invest in a 2nd joypod rig to fit servos on and strap on the back as you say, would like to have both the r/c pod and the stock pod hooked up to the contol brain either with a splitter or a switchable splitter.

The strap on pack doesnt need to be exposed to the elements nor have to be used directly by hand so it can be boxed away once complete.

The walnut shifter will be going ;) - too top heavy for unmanned roaming, it will send the F50 off course.

Definitely give Remap a shout. http://www.remap.org.uk/ We make free stuff for folk with disabilities and some of them are pretty technical... We have engineers in Ealing, Hammersmith & Hounslow, Brent & Harrow, Barnet, Croydon & Romford. That's just the London area.

You didn't think I JUST made robots, did you?