Schematic and basic PCB design are from: https://www.opendcc.de/elektronik/reverser/kehrschleife_e.html All credits to the creator! I made some minor changes to the PCB and created the Gerber files for PCB creation. The PCB Zip file contains all files, that are required for a PCB manufacterer. NOTE: These files are optimised so that they can be used via Elecrow.com If you order there, just add the zipfile and order: PCB Thickness: 1.6mm, Dimensions: 78mm * 78mm, Different Design: 1 (all the same) Building and using this schematic, board and/or firmware is entirely at your own risk. I am not responsible for any fault or damage in any shape when using this decoder.