Ender 3 Emergency Stop

thingiverse

This is a simple 2020 extrusion mount for an emergency stop button. I wanted something that would immediately cut motor power in case something got stuck, for example. Other methods, such as cutting printer power with a button, were not ideal because they also stopped the fans, leading to potential clogs due to heat creep. My solution was a software one, hooking into Marlin to kill the printer while keeping the fans running. This can be achieved by defining a 'KILL_PIN' in the Marlin firmware and your board's pins file. This is an example of the pin I used on my SKR v1.3 mainboard. I utilized the X-MAX end-stop pin, as it was unused. If your button triggers when not pressed, you can reverse the pin trigger state in the MarlinCore.h file by changing LOW to HIGH. The button I used is available for purchase at https://www.aliexpress.com/item/32800114918.html. I've also included a contacts cover for the button to prevent debris from triggering the KILL state. Hopefully, this will be useful to someone.