Motor Controller Advice

I want to buy the DFRobot 4WD platform at the URL below(sorry the system won't let me insert a link because I'm a new user). What motor controller will be adequate to drive the four motors that come with it and power the microcontroller? I am using the Arduino Mega.

Motor Specifications

Green Motor ? Gear Ratio 1:120 ? No-load speed(3V):100RPM ? No-load speed(6V):200RPM ? No-load current(3V):60mA ? No-load current(6V):71mA ? Stall current(3V):260mA ? Stall current(6V):470mA ? Torgue (3V): 1.2Kgcm ? Torque (6V): 1.92Kgcm ? Size: 55mm x 48.3mm x 23mm ? Weight:45g

Yellow Motor:

? Motor Model: 130 Motor ? Output Mode: Two-way shaft output ? Gear ratio: 1:120 ? No-load speed (3V): 90RPM ? No-load speed (6V): 180RPM ? No load current (3V): 120mA ? No load current (6V): 160mA ? Locked-rotor current (3V): 1.5A ? Locked-rotor current (6V): 2.8A ? Size: Long 55MM W 48.3MM high-23MM ? Weight: About 45g

http://www.robotshop.ca/dfrobot-4wd-arduino-mobile-platform-4.html

I know the specs are not clear, so lets assume that all four are the "yellow motors."

Thanks, Lebowski

They appear to be using four of these:

http://www.robotshop.ca/dfrobot-6v-180-rpm-micro-dc-geared-motor-with-back-shaft.html

If you look in the specs for that motor, you’ll see they match what is in the robot chassis specs.

These are regular brushed DC motors, so the controller will likely be something that is a dual h-bridge design (so one controller per pair of motors - you’ll have to decide which pair to control per controller).

I would run the motors at 7.2 volts (using R/C battery packs or similar), and use two of these:

http://www.robotshop.ca/pololu-dual-motor-driver-9a-2.html

While not a cheap solution, they should be able to handle the extra current requirements for the motors running at that voltage (something you might have to call about is whether the motors can -really- handle the higher voltage - the robot platform page seems to indicate that they can go up to 12 VDC, but the motor page for the motors doesn’t indicate this).

You might also simply contact them - say you wanted to buy the platform, that you wanted to use an Arduino to control it, what do they recommend for controller/drivers for the motors (maybe you can get a package deal?)…

:slight_smile:

Thank you for the help. I will give them a call tomorrow.

I also have one more question. Since I don’t care about having independent control of all 4 wheels, would it be possible to buy one of those controllers and wire the motors on each side in parallel? That would be a max current draw of 5.6A per channel, which the controller seems to be able to handle.

Since I don’t care about having independent control of all 4 wheels, would it be possible to buy one of those controllers and wire the motors on each side in parallel? That would be a max current draw of 5.6A per channel, which the controller seems to be able to handle.

As long as you stay within the current limits, that should work OK.