I need some advice on using 24v scooter motors for a robot project.
ElectricAye
Posts: 4,561
I've got some kids who want to build a "real" robot made of metal and bike chains, etc. so I've been eyeing the 24 VDC electric scooter motors. Problem is, I know nothing about these kinds of motors, how hard are they to control via BS2 or Propellers, for example, or how exactly to make controllers for them. Poking around the internet, I've seen debates about buying geared vs. non-geared versions of these motors, various talks about what sort of H-bridges to use, or whether the standard scooter controllers can be hacked somehow. So I would like to know if anyone on the forum has had any experience with these sorts of motors and might want to share some thoughts, good links, horror stories, and the like.
Thanks.
Thanks.
Comments
Thought I didn't need a controller initially. Used a 40A automotive lighting relay for simple on/off control. Worked fine on the bench, but it arc-welded itself into position on the very first ride and I couldn't turn it off. Made for a very exciting first ride!
http://tncscooters.com/
BTW, if you used one of those 250W gearmotors and simply replaced the sprocket with a wheel, that would be much safer (chain-wise at least) and still plenty strong & fast. Maybe too strong & fast.
Oh, yes, that's a good point. Oops. I hadn't thought of that. Kids today, you know, they aren't like us when we were growing up. We used to ride our bikes backwards down and up hills all the time.
Yes, that's a big question mark for me. How controllable are these scooter motor things? Would an H-bridge controlled by a BS2 be able to tame them or are they just "too much". I think what the kids envision is something that can roam around outside in the grass and go up hills and shoot things with paint ball guns, etc. They saw some RC battle tanks at the local Robotfest a couple weeks ago and they (and I, I guess) are using those as a sort of point of reference.
http://www.youtube.com/watch?v=eYh2JaHsdak&feature=plcp
Is there any reason the motors wouldn't turn in reverse if you switched the polarity?
I'd like to build a robot powerful enough to get around outside sometime (maybe to mow the lawn or plow snow). It seems like these scooter motors would be a good option, but I'd definitely want it to be able to go in reverse.
(I've bookmarked the scooter sites you listed in the other scooter moter thread.)
Maybe this guy... http://www.youtube.com/watch?v=ktyRiTv9qsI&feature=related
Hmmm, yes, you might be right about it being too powerful for kids. I'll have a look at these Power Wheel things and see what can be done. I think the kids are into something that looks serious though, so I've got to at least provide the appearance that we're not recycling mere toys or whatever. Or maybe it's just my own repressed yearning to use robotic armies to conquer the planet that is erupting to the surface... finally!
That sounds like an interesting idea. I'm sure autonomous robots roving the 'hood will be against the law, but if I can attach a stray mother-in-law to one, maybe that would be a loophole worth exploiting. I'm betting that I could get a whole lot of free electric wheelchairs if I'd offer to take the mother-in-laws that are often attached to them. I know I'd be willing to give up mine for free if there were any takers.
I'm not sure, but I have the impression that electric wheelchair motors are larger than a lot of those scooter motors.
One concern I'd have about electric wheelchair motors would be finding a replacement if I needed one. It would be kind of nice to be able to get four of the same motor and to be able to replace one if needed.
However, I wouldn't say no to some free wheelchair motors.
http://www.youtube.com/watch?v=engi16bLJe0
I picked an old thread because, this idea has been done before in some fashion or another, though I can't find a finished project.
My daughter had this in the trash and almost got picked up by her service, I had to smack myself because, I didn't instill it in her to call me first, when she decides to pitch possable useful items.
In an initial check of the system I found a loose connector and a broken battery cable, the rear tire has to be replaced because of flat spots, 'kids will do it every time', there must be pretty good speed out of it, and the brakes work well, to turn a round wheel into a square one.
I'm hoping to get a balancing bot with a grim reaper type rider put together for Halloween. This is a 24vdc chain drive system, I'm wondering if the motor controller can be hacked, or to go with something different. I want to use a Propeller and Memsic 2125 for the brains, it will definitely need an XBee, as I can't run that fast anymore. I want to include some failsafe's like a ping sensor, brake control and a way to cut power, if anyone has ideas they would like to share, I would appreciate it.
Also I have been sitting on this wheelchair base for a while now, would make a good mule or electric guard dog. I don't want to make drastic changes on it, may need to use it for its origial intention someday.
Mike