Ender 3 Emergency Stop Unit

This is an emergency stop unit which disconnects the 3D printer mains power supply by a trigger which comes from the smoke detector, switch or other source that can be added. This is a further line of defence against the possibility of fire. Once smoke is detected the source of heat on the 3D printer is removed. Thus limiting any fire, I HOPE. I have implemented this on the Ender 3 as in the photos.


THE WARNING

Always have thermal runaway detection active in your firmware. I had to install Marlin 1.1.9 for this to work on my machine. Also, we are not supposed to leave 3D printers unattended. However, we have lives to live and this is not always possible, so another line of defence against fire is this emergency stop unit. The mains power supply is 240 volts. Take care when building this unit as 240 volts is dangerous. If you are not happy in building a unit which involves mains supply, seek support.


THE CIRCUIT

I have adapted the circuit design from "digimatic" and