Ender-3 circuit board holder for bedlevel sensor

thingiverse

I've always been impressed by the automatic bed leveling feature, and since petsfang duct offers an option to install one, it was only a matter of time before I purchased an inductive bed level sensor. Of course, I could have ordered a complete set from TH3D, but where's the fun in that? Plus, I had some special ideas in mind. My requirements were: 1) No cutting of wires (you can rebuild everything - almost) 2) Reusing all parts (including the Z-endstop) 3) The fan for cooling electronic components is connected to the part cooling fan (I'm not a fan of the idea that cooling electronics depends on cooling printed parts) After researching online, I created a simple circuit for my sensor using my breadboard and it worked quite well: My circuit consists only of an optocoupler, a terminal for 24V, and some pinheaders. On the 24V side, there are pin headers for the cooling fan, the hotend fan (they're always on), and my inductive sensor. On the 5V side, I have a connector to the SPI-header and a connector to the Z-stop pin on the motherboard. I used the original endstop as a failsafe option to prevent nozzle crashes into the buildplate, should the inductive sensor fail for any reason. After soldering the circuit onto a piece of perfboard (about 18x50mm), I wanted to hide everything inside the electronic case, so I printed this small holder: For printing, I rotated the object by 90° around the Y-axis, used 0.2 layers with 30% infill, and accidentally added supports (I don't think they're necessary here). It turned out that pushing the board into the holder is quite difficult, but after some trimming of the board edges and making notches on the board, it snapped in place nicely. I didn't try to remove the board again - that could be a bit tricky... Maybe this will be useful for someone else - I'll also upload the FreeCAD project so you can adjust the sizes if you want.