Ender 3 bed leveling sensor

thingiverse

Use this to get almost free automatic mesh bed levelling for the Ender 3. The only extra parts you'll need are perhaps some M3 bolts, an SG90 servo, and some glue. This design is superior to directly attaching the micro switch to the arm because the wires connecting to the micro switch won't be bent every time the servo rotates. I originally used a design where the micro switch was attached to the servo arm, but every couple of prints, the wires would break and I'd have to re-solder. This one lasts much longer and works just as well. You'll need to sand down the inside of the track and the outside of the piston so that the piston slides down the track with a smooth, play-free motion.