Go Down

Topic: Using the Megamoto Shield to control a wheelchair (Read 1 time) previous topic - next topic

wilderbuchanan

Hi Everyone,
I am new with Arduino and i was wandering if someone could lend me a little help in getting my wheel chair running via Arduino.  I am using the Megamoto controller (http://www.robotpower.com/products/MegaMoto_info.html) and i can't figure out what electrical and code configurations i need.  I have a car battery hooked up to the power supply and a large motor that drives the wheelchair hooked up in the motor connection. I have jumpers at at D11, D8, D3, and A0 positions.
Thanks for your time,
Wilder

Germ

That page you linked has an excellent user manual down at the bottom for getting things started.
Have you read through it and do you have specific questions?


aarg

You have piqued my curiosity. Don't wheelchairs usually have two motors, one for each wheel?
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

nickgammon

Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

MorganS

The Megamoto should be able to run a wheelchair, but it's probably close to the limit of this chip's performance. Check how hot it's getting.

Since the chip can withstand high voltages, I would put 2 car batteries in series for (nominal) 24v. Even if the motors are 12v, this will reduce the current through the chip without overheating the motors. (Just limit your PWM maximum to 80% or so.) Unfortunately the Megamoto shield has some other components like the power LED which won't take this voltage. I would let them burn out by themselves.
"The problem is in the code you didn't post."

wilderbuchanan

Last night after about 6 hrs of work i was able to get the motors to run.  However, i realize that i need to learn how to program and work with the Arduino first, before jumping back into this project.
Thanks for your time,
Wilder

RayLivingston

I would think that H-Bridge would be really marginal for a wheelchair. You might consider using these instead:

http://www.ebay.com/itm/50A-Single-H-bridge-Motor-Driver-Module-PID-F-Arduino-Intelligent-Car-Robotic-6-/291041496732?pt=LH_DefaultDomain_0&hash=item43c36cce9c

These work really well, and will withstand significant over-load for short periods.  I use them with motors that draw up to 85A at stall, and have never blown one, other than when I did something stupid.

Regards,
Ray L.

Germ

I would think that H-Bridge would be really marginal for a wheelchair. You might consider using these instead:

http://www.ebay.com/itm/50A-Single-H-bridge-Motor-Driver-Module-PID-F-Arduino-Intelligent-Car-Robotic-6-/291041496732?pt=LH_DefaultDomain_0&hash=item43c36cce9c

These work really well, and will withstand significant over-load for short periods.  I use them with motors that draw up to 85A at stall, and have never blown one, other than when I did something stupid.

Regards,
Ray L.
Those look awesome I'm also looking for one with higher volts. I am thinking about modifying a 24v scooter.

RayLivingston

Those look awesome I'm also looking for one with higher volts. I am thinking about modifying a 24v scooter.
Higher voltage ones tend to be a lot more expensive.....  But you can get an amazing amount of torque out of a very small motor using a planetary reducer.  I have one product that uses a 12V/80A RS-775 motor to develop 35 ft-lbs @ about 60 RPM - MORE than enough speed and torque for a wheelchair.

Regards,
Ray L.

Go Up