uArm calibration issue


I´m having trouble calibrating my new uArm metal.

I´m using the arduino library from here : GitHub - uArm-Developer/UArmForArduino: Arduino uArm Metal Library (uArm Metal only)

When running the calibration, i do the following :

  • press “c” to launch the calibration process
  • put the arm in the callibration position and press “1”

IMPORTANT : I actually don´t kmow what the correct callibration position is. I´m supposed to orient the servos at 45, 130 and 20 degree but I don´t know how the angles are measured.

Anyway, i tried with different positions but every time, the values returned for offsetRot, offsetL and offsetR are “ovf” (overflow I gues, I´m new to arduino).

I also wrote a short programm to try to understand the issue. In fact, every time I try to read the angle of a servo, i get “ovf” in return.

Could it be that there is a hardware problem with the servos? This would mean that all servos have exactly the same issue.

Or am I just missing something / doing something wrong?

Thanks ind advance for your answers

P.S. I´m also sending a support ticket to uFactory


I noticed that while executing the calibration, there are some servos that return :

I´m just guessing, but for me this means that the servo doesn´t work properly.
However, it´s interesting to see that if i reboot the arduino (unplug/replug), it´s not always the same servo which has this error.

Hi tschild,
1, Can I have your ticket number in Support, pls?
2, Can I have link you refer to as Calibration in Github? This is the old version for Calibration.
3, Pls refer to our page first for Calibration


Hi Poppy,

Thanks for your reply.
Somehow I couldn’t make a ticket, I couldn’t log in. I instead wrote an e-mail to

I tried an older version of the UArmForArduino library (6.0) qnd it worked better.

I’m still wondering why it doesn’t work with the new version.

Hi Poppy, I also need to know what the correct way to calibrate the uarm Metal is. The link you posted is a link to the Chinese version of the main site, do you have a link directly to up to date English instructions on how to calibrate the uArm?

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