View Full Version : Arbotix-Pro doesn't recognize servos

07-08-2015, 02:28 PM
Hi everyone,

Recently the Arbotix-Pro board on one of our robots stopped working for an unknown reason. The robot was working perfectly fine, running the PS3 demo and walking. After one rather "normal" fall, the robot wouldn't move anymore.

We tried to replace the Arbotix-Pro board with one from another robot and everything was back to normal. So I imagine the problem is in the board, although I don't know what it might be exactly.

This is the output from the dxl_monitor:


Any ideas of what might have happened?

Thank you in advance.

07-08-2015, 02:45 PM
Can it find any servos when testing with spares? It is possible that the impact caused issues with a solder joint somewhere in the dxl communications ICs, specifically the read enable. Also possible that something inside the chassis shorted one of the dxl ICs during the impact. If you have a logic analyzer, try searching for servos while monitoring the TX and RX pins of the DXL UART at the STM32, the TX enable and RX enable pins, and the DATA line at the DXL connectors. The schematic is at the Interbotix github 'ArbotixPro' repo (https://github.com/Interbotix/ArbotixPro).

edit: Another possibility is that the 5V voltage regulator got damaged, which would cut power to the TX side of the DXL ICs and the RPi2. Much easier to check that the 5V supply is still functioning than hooking into the DXL ICs if everything stopped working.