FirmataVB and servos


Was hoping someone would be able to help me out. I baught a continuos rotation servo hoping to connect it to pin 9 of my arduino duemilanove (PWM). However when I do this nothing seems to happen. Im able to wire basic LEDS up to the non PWM outputs but the servo refuses to move.

A link to the servos datasheet is here:

I was hoping someone would be able to set me on the corect path with it please.

Thanks very much, Phil.

More questions than answers, I'm afraid. How are you powering the servo? Is the ground of that power source connected to the Arduino ground? How are you telling the servo to move?

The servo is wired as so:

red = +5v on arduino
black = ground on arduino
White = pwm digital output from arduino

the arduino has firmata on it and I'm using the instruction:


thanks allot.

Ok, so from what I can work out is that this servo is actualy a complete rotation servo and is therefore not proportional and can not be controlled acurately with PWM.

After doing a bit of diging around I have come across a servo that is sold as being a single complete rotation (360degrees) and still proportional.

this servo is the GWS S125 1T Servo.

Am i correct in thinkin that this servo can turn 360degrees and still be controlled with PWM to acurately adjust its position?

If you can recommend a servo that is better than this one, or is more suited to my needs then please feel free to share.

Thanks very much, Phil.

If you can recommend a servo that is better than this one, or is more suited to my needs then please feel free to share.

Without explaining your needs, who can say. That being said, you should be able to make the continous rotation servo rotate in either direction and stop. What is the code you tried to use? Google for "sail servo" for one that can make several turns. Do note that directly powering a servo thru the arduino is probably not the best choise. Best use a seperate power source rated for a couple of amps.

Ok here's what I need: a servo that can be moved to 0degrees, 100degrees, and 280 degrees.

It must be able to acuratelt move to these positions.

Thanks, Phil.

Is anyone able to confirm that the GWS S125 1T Servo is proportional and it's position easily adjusted. Thanks. Phil.

From a simple google search:

I purchased two of these 360 degree, GWS winch servos, and they seem to work as advertised; i.e., the positioning of the servo is fully proportional, over the full 360 degree range. I bought them from Acroname for $18 each, at:

Yes but I wanted to check as you can't always trust google.