Asked — Edited

Modify Servo For Continuous Rotation

This tutorial will explain how to modify a servo for continuous rotation. If you do not feel like modifying a servo yourself, you can purchase modified servos from HVW Tech

Servos normally have a limitted rotation of about 180 degrees. The number of electrical pulses within an ammount of time determines how many degrees the servo will move the shaft. As you can imagine, that is a great feature with many uses. However, servos would be great to drive wheels and tractor treads if they could spin continuously.

Many benefits to using a servo for driving wheels. The servo is in its own little packaging and self contained with gears and circuits.

Parts: 1 x Acoms AS-12 servo Enjoy RC Hobby 2 x 220 Ohm Resistors

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I have a Parallax Continuous Rotation servo. In the ARC program, do I need to select "Modified Servo" Control for it to work?

Also my servos came with instructions on how to set a start point, I haven't figured out how to do this. Do I need to set a start point for my servos before connecting them to the EZ-B?


Yes, a continuous rotation servo is also a modified servo. The continous rotations do not need a start point.

As for regular/standard servos, they need a start point. And I refer to that as calibrating or aligning. When you build your robot, make sure the arm, head, or whatever is attached to the servo has enough rotation. You can't use a continuous rotation servo for a head, or arm, etc... Because that will just continuely rotate:)

Watch the videos on the Tutorial section to see what the differences between a standard and continuous rotation servo are. The Tutorial section can be found from the top menu on this website.


OK great. I only asked because before I had used these servos in a Ardunio project and well...lets just say I no longer own one.

Also when you say "regular/Standard Servos, they need a start point. And I refer to that as calibrating" Do I need to calibrate a regular servo before use with the EZB?

I am sorry if I seem like a noob, I just like to gather as much information as possible before starting something.


Because a standard servo has a limited range of rotation, you want to ensure your servo is in the middle before attaching the robot limb, etc.

For example, if you put your robot arm on the servo, but the servo is in the furthest position, then the robot won't be able to move that limb any further in that position. Does that make sense?

Align your servo by

  1. You'll want to plug the standard servo into the EZ-B.

  2. Add a standard servo control (either horizontal or vertical depending on your layout)

  3. move the slide dial to the center

  4. attach your robot limb to the servo while it is aligned at the center



OK great that helps a lot. All I need a standard servo to do is to simply make the hood of a model car lift up. The rest of the project is a surprise ;)


Oh that sounds interesting! Way to leave us hanging eek