Servo and Motor Shield Confusion.

Hey Guys!

I am very new at Arduino (I just got started yesterday). I have the Uno, Motor Shield r3, and 2 standard Servos that I bought at Radio Shack:

I want to know how to hook the servos up to the motor shield or uno. There are very little tutorials with the depth I would like for some reason.

Thanks!

You don't need a motor shield for a servo, but you do need a seperate power supply for the servo as the Uno can't provide enough power for itself and the servo.

Servo will have 3 wires - +V, Gnd and a signal. The signal needs to be pulsed to move the servo, with specific timing. There is a Servo library that does this work for you as part of the Arduino IDE install, and there is information in the Playground on how servos work.

http://arduino.cc/playground/Learning/SingleServoExample

Thanks a lot for your help!

I have 2 questions though. What is this and where can I buy it?

And what is the advantage of having the Arduino Duemilanove rather than the Uno?

Looks like the bit you highlighted was the plug? No idea where you get one, but I would just poke some wire into the servo socket and use that if you are building a temporary circuit to test your ideas.

The white thing is a breadboard and you can get those in any elecronics store, ebay, etc.

Duemilanove (2009 in Italian) is for this purpose no different to the Uno. I think it is just a 'older' model with a different CPU.

Oh :slight_smile: I was just not sure how to hook it up because at a hobby store, I asked the owner if he thought it would work and he said definetly not ( mabye so I would buy one of his).

Thanks!

Sorry for double posting but I got my servo up and running but it only can only rotate 180 degrees. I was planning to use them as wheels. Would I need a whole different kind of servo or could I modify mine?

Generally standard servos just rotate 180 degrees. I have seen posts where people have modded the servos to do complete turns, so Google could be your friend here.

If you want to run wheels and you already have a motor shield, then why not just use a standard DC motor or a stepper motor? These can be run from the Arduino thru the motor shield. Examples in the Playground.

I think that is what I will do. Thanks!

And because in the picture you are not using separate power, please have a look at the two links in my signature for an illustration and solution of the next problem you will have.

Duane B

How would I connect 2 dc motors? would I need to use the Vin and GND inputs at all?

Its best to use separate power for motors as just like servos.

Duane B

The motor shield is best suited for motors or geared motors that are less than 2A stall each.
It can run 2 motors at one time or one motor bridged for a total of 4A at stall.

I would not use the motor shield for servo drive only.

I would also not modify the ones that you have, you can use them for all sorts of cool things like pan and tilt for Sharp IR or Ultrasonic sensors or a gripper... etc.

Instead, get the Parallax continuous rotation servo. This is a servo made for robotic mobility using servos.
Radio Shack sells them:

or you can get them at Parallax website.

Hi Sam
Check out this Instructable on the Motor Shield. It covers DC Motors, Stepper motors and code.

Hope this helps you!

SamKirkiles:
Sorry for double posting but I got my servo up and running but it only can only rotate 180 degrees. I was planning to use them as wheels. Would I need a whole different kind of servo or could I modify mine?

If you want to modify your servos to turn 360° then follow this tutorial:

Hope this was helpful, peace.

Or you can just buy continuous rotation servos.