What parts do I need to use the Arduino Uno to power a servomotor?

Projects General Guidance
1

I'm extremely new to Arduino and in general motion controls. I basically want to use the Arduino Uno to input a specified RPM in which a servomotor would then rotate at the desired RPM.

This is what I have:
Arduino Uno
SeeedStudio L298 Dual H-Bridge Motor Driver

My question is what other components do I need (ie breadboard/wires/etc.)?

Thank you!

**Student Senior Project

2

It depends what sort of 'servomotor' you are planning to drive.

3

Overview

Ray

4

The good news is that a servo has the driver circuit built-in so it only only needs power and a precisely-timed pulse-train from the Arduino.

The bad news is that a normal (unmodified) servo doesn't rotate 360 degress, so there is no "RPM", only a target-angle and the time it takes to get to that angle.

You either need a regular DC motor (controlled by a transistor/MOSFET) with some kind of RPM sensor, or a stepper motor. You don't need an H-bridge unless you need to reverse the motor.

A stepper motor usually runs off an H-bridge, but a stepper is usually used for a certain number of steps or an angle, rather for spinning at a certian RPM. And, they generally run slower than regular DC motors.

5

You also need a separate power supply for the motor, capable of supplying the required current. It is a very bad idea to try to power a motor from an Arduino.

6

@dgshelto - you need to clarify whether you mean the sort of servo that is used in flying model aircraft (which is the sort usually encountered on this forum) OR the sort of servo that is used in place of stepper motors on CNC machines. It sounds like you mean the latter. If so provide a link to the datasheet for the device you plan to use.

...R

7

DVDdoug:
a precisely-timed pulse-train from the Arduino.

please explain how to get a timed pulse.

8

I think you would be better off starting your own thread about this. I only looked at this because I had contributed before. I had forgotten what it was about and the OP never followed up his question.

What sort of timed pulse do you want? What have you tried? In what way has it not worked as you want?

...R

9

i have not tried anything with timed pulse.
trying to get a frequency of 20MHz or more. a pulse through a transformer would work.

10

mightyruler:
trying to get a frequency of 20MHz or more. a pulse through a transformer would work.

Your chances of achieving that with a 16MHz processor do not seem great. This seems unrelated to the original question so if you believe it's an Arduino issue and want further help with it I suggest you start your own thread explaining what problem you want help with.