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[on:]

I've been looking into using a hubbed motor for a single wheeled self balancing vehicle and I stumbled across the Focus Designs SBU V2 and now V3 which uses the Golden Motors Magic Pie 2 motor. I'm trying to determine how they control their motor. You can see from the attached diagram that there is no external controller which should make it easier to figure this out... I hope.

I'm wondering how I can connect my Arduino to this to control forward/reverse and speed? Would I be able to write my code to simply switch the reverse or should I consider switching it via phase? Would switching the reverse be fast enough, or smooth enough?

Also, the guys at Focus Designs have found a way to use the regenerative braking and a few other features I'd like to have. Man, those guys are smart. If I wanted a unicycle, that's the one I'd buy.

Thanks for any input,
Gyv

[Reply #1 on:]

The Magic Pie motors have the controller in-board.

The first version (which I have) didn't support reverse (and had fewer connections I think).  Standard throttle control is a 5k/10k pot - and
controllers normally switch off if there isn't the correct resistance in the right place for safety reasons.  You put a 5k or 10k resistor in the
place of the pot and directly control the "wiper" voltage.

reverse may or may not be a 5V logic signal - some reverse enginreering from the full kit of parts perhaps?

[Reply #2 on:]

MarkT,

Sorry, I wasn't clear. I realize the MP2 controller is in board, I meant how do the Focus Design guys control their MP2 on their SBU?

[Reply #3 on:]

Ask them?  Experiment?  I would imagine the speed control is as I describe, but as for reversing, I have no experience.

[Reply #4 on:]

I sent them an email earlier this week, no response yet. I'm tempted to buy one and play with it. I can always use it to make an e-bike if I can't get the Arduino to work. But its kind of a lot of money to spend just to play around. I'm sure you're right about the throttle input.

Thanks for the input, I'll report back if I find out anything or move forward with the experiment.

[Reply #5 on:]

I also like this self balancing vehicle, and I noticed that they were using this motors.

For regeneration brake may be they are using the Smart Pie in the SBU v3, perhaps the best option it is to contact with goldenmotor.com , I don´t think that SBU people will help you because this means loose money for them.

edit: There is a lot of information in goldenmotor forums, I´ve just found this:

I think this would be relatively easy to implement with an arduino, a gyro and doing something really fun!!

PS: please, excuse my english