Allows you to automatically reconnect your klipper system when using usb cable.

Since klipper can be used within different circumstances i'm trying to descibe my setup and usecase first.

My printer is have a mks robin nano 1.2 board with a raspberry pi 3b being connected via usb. The raspberry itself have a separate power supply. So i can turn the printer and the rpi off and on independently.

When i turn the printer off and on again klipper should automatically reconnect. Because i don't want to click restart and or restart firmware manually.

When unplugging the usb cable and plugging it back in again klipper should automatically reconnect. Because i don't want to click restart and or restart firmware manually.

I created this repository because i had problems with the solution being mentioned on the klipper repo to automatically reconnect klipper when the printer is being connected to the rpi with usb cable Klipper3d/klipper#835. restart is not working and i also ran into problems when executing a script within a udev rule.

Install the at scheduler and ensure python (python3) is installed.

apt-get install at

Copy the files reconnect-klipper.py and 99-klipper.rules to your host system.

Inside 99-klipper.rules you need to adjust the value of

• idVendor 1a86,
• idProduct 7523,
• path of the script /home/pi/reconnect-klipper.py and the
• base url http://localhost:7125 of moonraker.

To determine the idVendor and idProduct you can use lsusb command. Lsusb is also described here Klipper Issue 835.

SUBSYSTEM=="usb", ATTRS{idVendor}=="1a86", ATTRS{idProduct}=="7523", ACTION=="add", RUN+="/bin/bash -c '/bin/echo \"/bin/python /home/pi/reconnect-klipper.py http://localhost:7125\" | at now'"

Copy reconnect-klipper.py script in your home folder. Any other accessible path can also be fine.

Copy 99-klipper.rules into /etc/udev/rules.d/ and reload rules.

sudo cp ./99-klipper.rules /etc/udev/rules.d/99-klipper.rules
sudo udevadm control --reload-rules

This should do the trick. If you have problems try rebooting your klipper host or run reonnect-klipper.py manually by calling python reconnect-klipper.py.

With my mks robin nano 1.2 board i also run into a problem where the save&restart functionality after editing printer.cfg was not working. I always ended up with the error message telling me i need to restart firmware. Adding the line restart_method: command to [mcu] section solved the problem for me.

This might not apply for your setup. But when you run into problems (also applies for this script) just give this a try.

[mcu]
serial: /dev/serial/by-id/usb-xxx_USB_Serial-if00-port0
restart_method: command

[mcu rpi]
serial: /tmp/klipper_host_mcu