While I have the sensors mounted on 2 printers I am only wiring and changing firmware on 1 at a time. And I am starting with the homemade printer, Printilicious. The proximity sensor runs on 12v and the megatronics 3.0 board like all others uses 5v for it's sensors/end stops. So To resolve this I used a 10k and a 15k ohm resistor and made an in line voltage divider attached to the output wire of the proximity sensor..



I took this as a weekend project and all of my dvom/multimeter/labscope and related diagnostic equipment is at work. So here is my makeshift voltmeter for testing my circuit..



I got a stack of these tiny digital volt gauges off ebay a while ago and have used them for various projects. There is one mounted to each printer just so I can easily monitor the 12v output of my power supplies. They work great..



And today I am struggling with the trial and error of marlin settings.