Tutorial on how to configure Endstops in a 3d Printer
Bigtreetech Optical Endstop Light Control Limit Optical Switch For Ramps 1.4 Board With 3 Pin Cable 3d Printer Part - 3d Printer Parts & Accessories - AliExpress
Ramps 1.4 differences on the end stop pins, are there any?
TwinTeeth - Wiring the electronics | Diyouware.com