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Motor Question

For the project i'm working on, I need to move a body that will be about 60 pounds. What motors and motor controller should I use?

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Wheelchair motors can easily move 300lbs of robot at a good speed. Be sure your H-bridge or controller has a fail safe or it could kill someone.

Another option for the <100lb bot is windshield wiper motors. You can get brand new ones for $16 each from http://monsterguts.com/index.php?act=viewProd&productId=4

I too haven't settled on the H-bridge or controller yet though. Too many options, not enough knowledge in my head yet. Too many years since I did any electronics so I don't trust what knowledge I do have yet. (and I am trying to keep it really cheap, and it looks like once you go over a 2 amps, things start to get really pricey).

@Robotz012248 "Hey Dave, Have you done the EZ-B conversion on a wheelchair? If you did how did you connect the EZ-B to the chairs controller? Pics or wiring diagram would be great!"

I have a chair that I'm going to use but have not as yet interfaced the controller...I do have the programming cable and the programming software thou which can set every option that the chair can do, it gives me full control over every setting, speed, braking, etc.


I always try to apply the three main laws of Robotics....

A robot may not injure a human being or, through inaction, allow a human being to come to harm.

A robot must obey the orders given to it by human beings, except where such orders would conflict with the First Law.

A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws.

And yes the chair can move over 300 lbs but a 1 lb robot doing 60 mph can also kill.

You sound like you might be at a similar level to myself. May I ask your age and location? Perhaps we could compare notes and possibly help each other out. You are welcome to email me at my personal email; robotz12248@cox.net
@ Dave;
I would very much like to pick your brain and resources if you'd be open to sharing. Please feel free to email me personally.

I am in the Maryland suburbs of Washington DC, and I am 47 years old. I am a reasonably good programmer with Visual Basic 6, but trying to learn VB.Net, and want to follow that with C# (would have jumped straight to C#, but I have a project at work that I need to do in VB.Net, so it has to come first).

I am pretty technically inclined, particularly around software, but the last time I did any significant hardware electronics I was in high school, so it has been about 30 years.

I would be happy to converse directly. I am at alan at thetechguru dot net, however I think it would be useful to others if we share what we learn here on the forum, and we'll also get others to chime in with answers on the things we are struggling with.


Hi Lloyd,

Hey no problem sharing info, one of the easiest methods is to just operate the power chair joystick directly with two servo's.

The big issue with the chair electronics is that unless you are a licensed/registered wheel tech technician you cannot get any info or schematics etc from the manufacturer, believe me I know, I've tried, they covet their industry info. Pick a wheelchair manufacturer and try and get info on the inner workings of their electronics.

Even the programming cable I have has proprietor electronics built inside, very hard to figure out from scratch.

Hi all,

Great posts. I will be following this thread for my next project.
Alan I am in Northern Virginia. Small world.
I too am into the technical arts. My hobby has been Home Automation. I have been doing that for over 10 years. EZ B has introduced another hobby. I plan on integrating my projects into my existing Home Automation system. Like you my work comes first along with family. Looking forward to more posts!


I also did Home Automation for many years (Primarily with Homeseer software). Unfortunatly, with X10 I could never get the reliability high enough for an acceptable WAF (Wife Acceptance Factor) and without high WAF I could not spend the money for Insteon or other more reliable tech. Catch 22. At this point I have deactivated my Homeseer machine and shut down all the automation except in my home office where I do a little automation for security.

I can see the EZ-B as a great digital IO device at a fraction of the cost of other solutions, so after I build my Bot, I may take a stab at doing some more home automation too.

Thank you all for your input. I am going to try the sabertooth 2x25 controller and wider motors. I'll let you know how it turns out.
use a sabertooth 2x25 motor controller.
i almost have mine set up to use with the ez-b.
i actually already have the electric wheelchair remote controlled using a spektrum dx5e. view my youtube videos.

here is the full link if that didnt work for you

my two youtube id's are smartstuff2buy and robots4sale
so check out all my inventions.

the problem i'm having is when i take off my receiver from my sabertooth motor controller, the ez-b is not talking to my motor controller.
i'm using the modified servo movement panel, since it shows a stop, up, down, left and right button. its made for a continuous servo. the wheelchair is powered by 2 motors and its like a zero turn mower.

DO NOT use servos to control the joystick. thats more of the old school analog approach.

i know i dont have this 100% working, but i did the hard part of making the rc controller work, but i'm sure i'm missing something simple here.

guys, please help me find out why my ez b is not sending signal, or why the signal is not working for my sabertooth. i left the sabertooth set on r/c mode. i tried with and without grounding the sabertooth to the ez-b.

whoever fixes this problem will receive $5 on paypal, if i can narrow it down to 1 person that finds the ultimate problem!

Yes I have been looking at the Sabre-Tooths...

I haven't been playing around with the EZ-B enough yet but your radio is inputting a PWM signal to the Sabre Tooth so your EZ-B has to do the same, I think that the modified servo panel is outputting an on or off state, try a vertical or horizontal servo output hooked to your sabretooth and see what it does, set the servo to 35 which should be center/neutral , leave your sabretooth set to RC.

Not sure if that will work but worth a try.

I have to get to work on this chair controller, I'm thinking that they may output some kind of single wire I2C, need to do more probing yet.

ok thanks dave,
thegoodrobot@yahoo.com is my email if you want to see more of my r/c wheelchair videos. i made an r/c lawnmower by pulling a push mower. later i will make it all one unit so its not pulling it. trying to make it "smart" with ez-b. good luck
and i will try your suggestion tomorrow
The modified servo Movement Panel has the ability to select the positioning for fussy motor controllers.

press the Config button on the modified servo Movement Panel and move the positioning to values that will work. There is someone on here who is using the sabertooth without issues after adding that feature. Wish i could remember who
United Kingdom
Hi great project it Thegoodrobot it was Pacomms I believe with the working Sabretooth controller not sure so

Serching for post please stand by .......

Thegoodrobot did you not see my other post to your problem?

I think that just disconnecting your RC gear and plugging in the EZ B will cause the controller to do a safety shut down through loss of signal.

Also it's the outside pin of the EZ B not the middle one. Did you try this????????
I have a set of motors/gear boxes out of a Barbie Corvette power wheels complete with wiring harness if anyone wants to do some trading? I have opted for wheel chair motors for my my big bot and don't need these.
Hey winstn you need to put the same hat on your bot.

The sabertooth may shut down because of loss of signal but when I turn main power off then on, shouldn't it reset?

Also I used d0 and d1, only the signal wire into the s1 and s2, and the grounds from d0 and d1 to low negative side of the sabertooth.

I will work on it again next Friday.
I think I read all your posts about the sabertooth.
I am going to try a few more of everyone's suggestions and make sure I'm looking at it right.

United Kingdom
Yes I agree about the hat unfortunately its a mates and not mine.

The only thing I thought was that you used the wrong
Pin on th EZ-B board ports it's the outside pins on the V3 board that you should connect to the Sabretooth controller.

This is opposite to the V2.1 boards but not many people have those. I have both btw
Bret. What would you be looking for to trade for the motors/gearbox? I don't have much robot gear yet, but I have some computer gear, android phones, cash...

Let me know what you might be interested in.

Finally got my Sabertooth 2x12. Took some time to figure it out but I now have it working with 2 wiper motors and the EZ-B. Everything I read on the forums said to set the Sabertooth to RC mode. I got everything working when I set it to the microcontroller pulses mode. Dip switch settings are 1-off 2-on 3-on 4-off 5-on 6-off. Now to actually build the bot.