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Asked — Edited
Resolved Resolved by Rich!

Help With Modified Servo


I have 2 motors controlled via a H-bridge so I have a Movement Panel all set up for this. But, I also have a single modified servo I need to control from time to time. Obviously I cannot use another Movement Panel as I already have one, so I have a modified servo control. It works but a cannot reduce the speed, even if I change the min and max values in the config menu.

If there's a way, how can I use the modified servo at a "drastically reduced" maximum speed. Full speed is far to quick and will eventually cause damage (I have already stripped one servo due to this eyeroll). I've had a look through the learn section and script menu but couldn't find any info that would help me with this. Any suggestions would be most welcome and of course appreciated.

Steve. :)


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Changing the forward and reverse values in the modified servo control will change the speed at which it moves. The closer to 1 and 180 the value is the faster it is, the closer to 90 the slower it is.


Speed doesn't change much from 180 to 90 until you get around the value of about 124... I would assume it would be similar from 1 to 90 (around 55 or so)... you'll have to experiment with the numbers until you find the correct value that suits your needs....

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To add, and it may be due to an old version I am currently running (update is frozen at 40.1mb downloaded so can't update just yet) but the modified servo control may have a bug in that changing the values doesn't change the speed (not even if you put them both to the same value, the direction still remains as if it was 1 and 180).

The EZ-Robot 360 servos stop at around 107 or 108 (at least mine does however I did notice a hole on the side which may be a way to adjust stop position, I only noticed it while packing the servo away though so didn't get chance to check what it does) so closer to those is slower. Different servos will vary (you will need to find it out by trial and error).

And the EZ-Robot 360 servos do have a greater speed range and you can notice a difference even at the high speeds.

If you need to, for the time being, use the Servo() command, the servo position will determine the speed and direction as mentioned above.

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I tried doing that using various ranges, 1 to 180, 50 to 130, 80 to 100, and even 88 to 92. Non of these changed the speed and span at full RPM each time. Just to confirm it is an EZ-Robot continuos rotation servo that came with the dev kit.

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Add a normal horizontal or vertical servo control Set the port to that of the modified servo Change max and min values in the config to 1 and 180 Adjust the control to find the desired speed Make a note of the number for your desired maximum speeds for forwards and reverse Press release on the control to stop the motor spinning

Then use the Modified servo control and adjust the values.

It may be that ARC needs a quick update from DJ to address the issue I mentioned earlier (I'm still unable to get the latest version so it may have been addressed but from your comments I assume it hasn't).


In the modified servo Movement Panel adjusting forward left wheel servo speed from 180 to 120 really slows my modified servos down.... However, it doesn't seem to work with the basic modified servo control...

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Yeah same for me too. It works really well. Only thing is a cant have the 2 movement panels (the other being the H-bridge one).


I'll give the horizontal control idea a try and report back.

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So I'm giving the horizontal/vertical servo control a try but no joy. I then tried a mod servo control and when I press the arrows I can here the servo click but doesn't move (well a very very tiny bit). Tried a mod servo Movement Panel and I get the same. It did this yesterday but all of a sudden burst in to life, but not today.

Any ideas?

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Are you doing that in a new project or an existing one? To avoid any conflicting scripts, commands or controls try it in a new project.

Modified servo control will make it move forwards or reverse at full speed (regardless of settings due to the little bug). Modified servo Movement Panel will move forwards or reverse at the specified speeds (this one works OK). Standard Horiz/Vert servo controls will make it move forwards or reverse at varying speeds depending on the position set.

If they are not doing that it's one of two thing;

  1. Another control is also controlling the servo, use a new project to avoid this.
  2. The servo is seized or broken and may need some diagnostics to figure out the problem and fix it.
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Yeah did try it in a new empty project. No dice. stress

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Well thanks for your help guys. Just to update you, my modified servo burst back in to life again and tried a vertical Movement Panel and it worked, briefly. Then the servo packed up for good, only pulsing any time I hit a control. So ordered and replaced it with a standard servo and all is well.

Thanks again guys. :)