Endstop Accuracy

thingiverse

So it turns out using an end switch actuated by a spring-loaded screw is not the most precise method of setting your extruder in the home position. Upon watching people mount hall effect sensors actuated by magnets or ultrasound proximity sensors for both bed leveling or as end stops, I clearly saw how overcomplicated we make our stuff. Let's keep it simple, for me, you, and everyone who doesn't have time to draw and etch a circuit and write code for a system where only a 5V signal will do the job perfectly. On the picture above there is an infrared sensor, its datasheet as a PDF file shows us the simplicity of its working. You load it with 5-24V on the (+) brown wire and (-) blue wire, and as a result sticking something between the infrared will give a signal out of the white wire, the same voltage of the input. Moreover, the precision of it is around 0.03mm, and that's much more than we need to have the same home position over a long time span. So basically, what you need to do is get your hands on an infrared sensor like this one (PM-U24P), which costs the same as a Big Mac. Save yourself and your prints by printing its support, unfortunately, you can't use the one it comes with the printer because it's a little offset to the right so the already existing screw gets in the middle of the sensor. But you can use the 2x M2 screws, the 1x M3 screw, and its nut. Jack the coming +5V signal from the existing switch to the brown cable. Search the board for a -5V for the blue one and et voila, there you go, a perfect endstop, and you can still use the adjusting screw.