Asked — Edited

Questions With Rotational Servo Speed On Adventure Bot

When I load the example project, I get an Auto Position Control that includes directional arrows. However, when I press Forward or Reverse, only one servo moves. If I press Right or Left, both servos move as expected in opposite directions After reading the Calibrate Continuous Rotation servo Adjust Speed tutorial and watching the video, I added the Continuous servo Movement Control which required the removal of the Auto Position Control. Per the video, I changed my stop values from the default 108 to 90 and clicked Test on both Stops, with the Use checked. I was able to stop the movement as shown in the video The next step adjusting speed, with the Use unchecked. Unlike the video, I was only able to slow the speed a very small amount. My servos would only move at 95 or greater or 82 or less not the closer numbers shown in the video.

My questions are:

  1. Why can’t I set the slow speed?
  2. Why was the Auto Position control in the example?
  3. Am I now supposed to remove the control I added and put back in the Auto Position control I read many other posts on issues with rotational servo speed issues, but didn’t find a solution

Thanks, Frank

Calibrate Continuous Rotation servo Adjust Speed


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  1. You don't need to remove any controls. Start a new project instead. For example, you wouldn't erase the contents of a document simply to start writing a new document:D

  2. The reason for the Auto Position is to add a more fluid movement to the servos

  3. You may use the continuous rotation movement panel, if you like. There's no reason not to. The reason the calibration video mentions to use it is because you cannot calibrate using any other controls as easy

The speed of continuous rotation servos is not easily adjustable. That's one of the drawbacks. You can calibrate the servos to be STOPPED at 90. Then, following the tutorial, slowly move away from 90 in either direction one degree at a time to select your speed.

Here's a direct link the calibration procedure for reference for other readers:


Have you Tried the latest ARC and included project?


Just saw it. Testing speed control now

Thanks Frank


Here are my findings. Please note that the Windows version was 2016.11.07 and the IOS version was 2016.11.06 (latest I could find)

This was tested on the Adventure Bot example in the release ARC Windows release 2016.11.06 added speed sliders on the Continuous servo Movement panel.

User-inserted image

However, there are a couple of issues:

  1. The speed sliders only affect the forward and reverse speeds, i.e. the right and left speeds are still set on full speed

  2. The range of speed control is not good. The control only seems to be effective in the top ½ of the slider

By comparison, the sliders controlling the h-bridge on the Roli appear to give full range control

The ARC IOS Mobile release 2016.11.06 has this display

User-inserted image

There are also some issues:

  1. Does not add any speed control sliders. The release states there is an analog speed adjustment

  2. The forward/reverse & 45degree controls work fine, but at full speed. But, the 90 degree controls do not cause any movement

Regards, Frank


When did you purchase the adventurebot?


I built it from the developer kit and parts I ordered. Is it possible I have the wrong servos?


When did you get the developer kit?


okay, let me get back to you tomorrow


im having replacement servos sent to you. I believe the ones you have are faulty. Apologies, the replacements will have proper speed control ability.


@djsures The new replacement servos work great!

I really enjoy have a wide range of speed control now.

Thank you very much Frank