Ender 3 Raspberry Pi rear box remix with 50mm fan and OpenScad files

thingiverse

This is a new LID design for the Ender 3 Rear Control box thing that only fits the box with rear Raspberry Pi socket cutouts. See: https://www.thingiverse.com/thing:3178072 I wanted to add a 50mm fan and extra slots for a Raspberry Pi Camera cable and additional top rear cable entry. I included the layout of the box's internals, which might help others. I used two LM2596 voltage regulators. Regulator A converts the main PSU 24v line into 12v for fans and lights. Regulator B converts the external 12v power jack to 5v to power the Raspberry Pi. The twin relay board is controlled by the Pi using OctoPrint and the "Enclosure" plug in. One relay controls the mains side of the printer power supply, while the other relay switches the 12v regulated line to turn on the 50mm fan and LED lights. Vcc on the relay board goes to 3.3v on the Pi, and JD-Vcc goes to 5v on the Pi (remove the jumper link). To fit everything in the box, I removed all mounting lugs except for the Pi. The other lugs were replaced with 6mm high pillars. The Pi lugs needed drilling through and used m2.5 bolts and nuts. The choc block at the back is raised 6mm on two pillars to allow easier access and get cables under it. Connections from left are: GND, 24v, 12v then switched 12v. I added a 50mm fan grille mesh holder that lets you sandwich fine material mesh between the lid and this part to stop dust getting in. Without this part, the flexible mesh might rub or snag on the fan. OCTOPRINT POWER RELAY STICKING ON? - IMPORTANT NOTE ON SWITCHING MAINS TO THE PRINTER PSU... Some cheap power supplies like the one in the Ender 3 have a huge initial current spike when first switched on. This is called "inrush" current. This inrush current can weld the Octoprint relay contacts closed (on) and damage the relay. See my other thing which is an active inrush eliminator: https://www.thingiverse.com/thing:4413002