Ender 3 Rear Case Remix

Used OpenSCAD to import the original left case design and added a cutout for a lighted momentary push button for the Raspberry PI with a Pimoroni onoffshim installed. I used a Ulincos U16F1 with a 16mm mounting hole.

Two options depending on whether you opt to install the fan in the original design (I did not).

I opted to use a buck converter with a higher rating (5A) that uses XLSEMI's XL4015 chip. It has different hole placement, but I just secured with a single screw. I connected the input of the converter directly to the 24V power supply and modified a short USB cable to connect to the onoffshim.

When you switch on the 24V supply, the onoffshim triggers and a couple of seconds later the PI is up. You can set Octoprint to automatically connect to the controller. To power down, first depress the PI button for 1 second or more. It will flash to indicate the PI is being powered down cleanly. It will flash three times just before it is done. You could then power off the 24V supply.

I chose to modify the setting for the onoffshim to use a different LED pin. After installing the software you would need to edit the file at /etc/cleanshutd.conf and change led_pin to read led_pin=27