Multiple motor with Arduino Uno Advice

Hi all Arduino hackers,

I have a project in my head and I am very new to this Arduino world. For my project I need to drive 3 motors. 2 motors need to be drive motors and 1 just for turning wheels. I currently have a motor that would be for turning wheels. I am very lost with the drive motors: brushless, stepper, H bridge. Could any one explain what I need to be able to drive those 2 motors?



If by "drive motors" you mean motors that you have control over speed, then regular DC motors with PWM would be sufficient. (And some power control, such as a MOSFET) If by "drive motors" you mean motors where you need very precise position control, or very precise rate control, then you need either stepper motors, with a stepper driver circuit, or continuous-rotation servos, which just take a single pin out of the Arduino plus a power source. If you can draw a sketch of what you'll use the motors for, then we can be better at recommending specifics.

Ok, So I think I would need 2 continuous-rotation servos that take up 1 Arduino pin each. Is that what are actually called? Continuous-rotation servos?


jwatte: ... continuous-rotation servos...

I wouldn't call "continuous-rotation servos" precise - considering they've been neutered of their "servo" control (for the OP, a continuous-rotation servo is a hobby-grade servo which has been modified so that it no longer moves to a given position, but instead continuously rotates; as such, it is no longer a real "servo", but is still called such - mainly due to "inertia". Technically, it is nothing more than a DC gearmotor, which, to a certain extent, you can control the speed - but only with some level of precision; there is no feedback or speed control in such a modified "servo").

A ‘servo’ is any motor with a feedback controller. I would expect the speed control of the “continuous rotation” servos to be reasonably precise, based on the same position encoder as used for positioning the servo. And, yes, a “continuous rotation servo,” be it “hobby grade” or not, will probably work for propulsion, assuming that it delivers enough torque for your platform weight.

If all you need is a motor with speed control, then a geared DC motor would be sufficient. You can control its speed with PWM. If it also needs to run backwards, you will need an H-bridge or similar circuit to drive it. If it’s just forward, a single pin out with a MOSFET driver and a kickback diode would be sufficient.