uArm only sometimes executing program - other times "stuck"

uArm Serial No.: UARM-0725160138
Firmware Version: 2.2.1
Operation System: Win 7
uArm Controlling Method: Arduino IDE 1.6.12 (in Visual Studio 2015 Student) with the uArm Library 1.7.2

The uArm begins the operation after receiving a command from the serial port. Usually it works the first time after plugging it in, but sometimes it just stops. The uArm additionaly sends its actions as text to the serial port (for debugging). Sometimes in the middle of the sentence sent ot the serial port it continues with random letters and numbers, for example: “|°°?üQa7`=&”. This is the point where the uArm also stops moving. However, the uArm does fully execute the program at other times.

What is happening? I first thought it was the memory, but there is still around 40% memory left:
Program size: 19,998 bytes (used 62% of a 32,256 byte maximum) (4.21 secs)
Minimum Memory Usage: 1239 bytes (60% of a 2048 byte maximum)

Also the ABSOLUTE positioning in the uarm.moveto() command is very unprecise, I had to create a “correcting position” function which actually reads the position and corrects itself. Why doesn’t the command moveto() with ABSOLUTE positioning move the uArm to the correct position? For example: moveto(x, y, 15, …) makes the uArm move to z =12. ??

Thank you for your time,


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Hi Ben,

You are using the old uArm library with the new firmware.

Please update the uArm-Arduino library to 2.2.1

My mistake was using the library v. 2.2.1 before the update of the firmware, which didnt work obviously. Thats why I downgraded. However, later I did update the firmware and with the library 1.7.2 it seemed to work, so I stayed there. Thank you for clarifying this!