Automatic printer switch off

thingiverse

I wanted my printer to switch off automatically after printer job done and not caring about fans still running. So I decided to create this thing. The Power of my printer is derived from an ATX Power adapter and the Printer On switch basically shortcuts the green wire of the ATX supply to ground. When my printer jobs finishes, my printer does a homing of X and Y, so wenn X axis reaches home position, this could tigger a limit switch.(switch off) So the basic Idea is to create a second "switched" On switch. This is an electrical path from ground to 2nd onSwitch - to extra limit switch - and finally to to green wire. So when you successfully started your print job, you would supply the printer from the 2nd on switch. Actually a simple limit switch is not sufficient: When homing triggers the limit switch it will disconnect the power, but when looses force it might snap back , providing power again to the printer. So the printer will just make a reset, but not switch off. You need something like a latch. This is what I realized here. A Video showing the functionality of the switch is at http://youtu.be/8Bw0QOTs684. Here you see my installed auto-power-off :http://youtu.be/IdwWwwvrUUY Instructions You need the plastic print a 5mm diameter 10mm small spring a small skrew to fix the spring A limit switch with 10mm Hole distance 2 M2x8 skrews top Print with 0.15mm layer height, no support use a file and 5.5mm drill to finetune the result. Attach the spring to the latch, insert the latch into the case. mount the spring with the skrew, then insert the locker and finally mount the limit switch.