Team Exterminate Antweight Robots

Modifying a Micro9 servo to 360 degree movement

These instructions show how I modified a Micro9 servo. This is (as far as I know) the third incarnation of this servo, and I purchased mine in August 2004. Feel free to follow these instructions, but if you damage anything by doing so then the risk, and the responsibility are yours.

This is the Micro 9 servo

The four screws you will need to remove are at the back of the servo

Here the screws have been removed

Here the front plate has been removed, revealing the gears

The output gear needs to be removed. It's jammed tightly onto the output shaft so you'll have to be firm. I took mine off with a small pair of pliers. Be careful not to break anything though!

I have outlined in red the protrusion that prevents the output gear from rotating 360 degrees. You will have to remove it. I used a Dremmel. Once again care is needed not to damage anything.

Here the protrusion has been removed.

Here's a closer look at those gears. You can see that the output gear has double thickness over half its circumference. This extra material is what the protrusion in a previous picture jams against, and is what prevents 360 degree rotation.

Most of the gears have been removed showing the potentiometer (on the right) This is used as a feedback mechanism by the servo to tell it where the output gear is positioned. The potentiometer (pot) will have to be glued in place at a middle position.

Connect the servo to a reveiver and a battery and make sure your transmitter is set to a centre position.

Rotate the pot until the motor doesn't rotate. This is the centre position, but may not actually look central. You have to match it up to your own transmitter.

Glue the pot in place

You will then have to widen the bore of the output gear with a 1.5mm drill (just twist the drill bit in by hand) so that it rotates smoothly on the pot shaft, as in the previous step you glued the pot shaft in place so that it wouldn't rotate.

Lastly, re-assemble and you should have converted a servo into a motor for an antweight robot.

Good luck.

Disclaimer: Building robots can be dangerous, any damage caused by following these instructions must be your own responsibility. Please take care.