Ender-3 circuit board holder for bedlevel sensor

thingiverse

I always admired the automatic bed levelling and since the petsfang duct has the option to install one it was inevitable that I purchased an inductive bedlevel sensor one day. Of course I could have ordered a complete set from TH3D, but where is the fun with that, plus I had some special ideas in mind. My requirements where: 1) No cutting of wires (you can build everything back - almost) 2) Reusing all parts (also the Z-endstop) 3)The fan für cooling the electronic stuff is connected to the part cooling fan (I don't like the idea very much, that cooling the electronic is dependent of cooling the printed parts) So after some research in the internet, I put a little circuit for my sensor on my breed board together and it worked quite well: My circuit contains only 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 are always on though) and my inductive sensor. On the 5V side I have a connector for to the SPI-header and a connector to the Z-stop pin on the motherboard. Here I used the original endstop as a failsafe option to prevent crashing the nozzle into the buildplate, should the inductive sensor fail for some reason. After soldering the circuit on a piece of perfboard (~18x50mm) I wanted to hide the whole stuff in the electronic case, so I printed this little thing here. For printing, I turned the object by 90° around the Y-axis, used 0.2 layers with 30% infill and by accident with supports (I really don't think they are necessary here). It turned out that pushing the board into the holder is very hard, but after some cutting the board edges and making some notches on the board it snapped in quite well. (I did not try to remove the board again - that could be a bit tricky…) So maybe this is usefull for anyone - I will also upload the FreeCAD project so you can change sizes if you want.