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Michael Templeton@templeton_m· 1 view

Keep loosing nano while programing.

I have an ongoing issue where if I adjust any line on my AR4 software, the nano board quits talkin. I have a servo gripper and a sensor running on the nano. In windows device manager the port is still showing. I can open Arduino IDE and talk to the nano, but to get AR4 to talk again I have to reboot windows or unplug and re-plug the usb to the nano.

I have had this issue for a while, but I'm now implementing the robot and having to make small adjustments. A simple 1 min adjustment is taking 15 mins.

I have the latest version on both the teensy and nano. Have replaced both teensy and nano, all usb cables (using good cables). Using AR4 6.3

Any help here will be greatly appreciated.

Comment 2

Chris Annin

This sounds like the Nano COM port is getting “stuck open” or the Nano is briefly resetting, so AR4 can’t reacquire the port until Windows/USB resets it (unplug/replug or reboot). A few things to try:

  • Make sure nothing else is connected to that COM port while AR4 is running (close Arduino IDE/Serial Monitor completely).
  • If the servo/gripper is powered from the Nano/USB, move it to an external 5-6V supply (shared ground), servo noise can cause resets that leave the USB serial in a bad state.
  • Try disabling/enabling the COM port in Device Manager as a faster recovery than rebooting.

If it keeps happening, I can add/adjust AR4’s Nano reconnect logic so it fully closes and reopens the port cleanly (including stopping any background read thread) and retries automatically if the port drops.

Michael Templeton

This is a new install of windows just to run the AR4, so nothing should be grabbing the com port. The servo is powered separately with common ground.

I'll try the com port disable/enable for the reset.

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