OSR servos are overextending and straining the servo arm

Hi everyone,

I just recently built my OSR 2 with the pitcher modification and I am running everything through an ESP32 board. I managed to get the sketch onto the board fine, everything lights up. I have all the wires installed into their corresponding pins yet when I give the device power the servos seem to go into overdrive and try to drive the arms back as far as they possibly go creating this distorted mess. I have attached an image of what it looks like when I give the system power.

Please help I am going crazy trying to figure out what I did wrong.

Usually the ground connections coming loose tends to be the issue when the servos go haywire. Looks like the ground wire going from the ESP32 doesn’t have much slack, but that might just be the angle of the picture.

The procedure to attaching the servo horns is to first power the servos on so they go to the home position. Then attach the servo horns so they are at a 90 degree angle to the servos (i.e. pointing straight at you as you look at the case face on). Then attach the arms.

Did you do that, or did you attach the servo horns when the servos were powered down and at some random position?


yeah, servos weren’t homed before you installed the horns. Easy fix. Just hope the servos didn’t hurt themselves straining against each other.


I will try that, as for the pitch servo how do I attach that so it is zero’d? Should the servo horn be 90 degrees when compared to the servo it is closest to? The build instructions were not that in depth regarding angles and degrees everything attaches on at.

The May 2022 build instructions look pretty clear to me about those questions. What instructions are you following?

Here’s what you find in the instructions I’m referring to:

Close the Arduino IDE and unplug the Romeo from the USB cable. Wait a few seconds, then reconnect it. The servos should automatically return to a neutral position. With the servos in this position place the Futaba 25T M3 servo horns onto the servos so that they are at right angles to the base. Tighten the tiny screws on the servo horns in this position.

And for the pitcher:

Power up and reset the OSR2. This will drive the pitcher servo into the neutral position.

Now install the servo horn and pitcher arm with M3x10 bolts and M3 washers. The arm should be parallel with the pitcher plate when the servo is in the neutral position.

So the horn is parallel to the servo for the pitcher when it’s powered and in the home position.

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Nice work team, I see all of the correct responses here.

Don’t hesitate to Dm me @Overspike if you need more assistance.

Thank you Thanny, I apparently skipped over the section regarding the pitcher arm. As for my problem it was actually two fold. Just in case anyone has this issue happen to them here is the solution. 1) make sure the pitcher arm servo is zero’d and the servo horn is installed at a 90 degree angle to the main servo horns controlling the up and down motion. 2) adjust the length of the fish eye bearings, making them too tight does not give enough play when testing the max height and some pitching angles.