Ah, the woes of printer bed leveling. Unless you have a fancy 3D printer, bed leveling is a tedious task. [Rupin] got tired of messing around with his printer, so he decided to make his very own bed leveling sensor.
The goal was to create a Z-axis probe that works as both an auto-leveling sensor and as an end stop. He originally was trying to design something using a servo motor probe, but ended up chucking the idea since the motor was noisy and calibration was difficult.
He’s since switched over to use a solenoid actuator with an optoisolator to determine the position. The actuator extends an M3 screw which will touch the bed — as the position is adjusted, it is possible to adjust the bed using software for a perfectly level bed, every time.
Relatively speaking, the hardware aspect of this was quite easy to do. [Rupin] is now cleaning up the code and when he’s happy with it he will publish it as part of the Marlin branch of printer firmware.
Alternatively if you’re looking for more of a challenge you can try using temperature force sensitive resistors to level your bed…