Railway HO project Signals and electronics for my HO scale railway project

This is my own project for building model railway HO scale (1:87) Deutsche Bundesbahn (DB) style Era III (1945-1970) Train Signals following this specification.

This is part of a complete project involving:

• 3D printing (Maker World)
• Electronics (PCB design and soldering) (github)
• Arduino code (demo, DCC and JMRI integration) (github)

Resources

wikipedia signals in Germany

These sites were a great source of inspiration:

• stummi forum (DE)
• [digital bahn (DE)] (https://www.digital-bahn.de/info_kompo/signale.htm)

Project

This project contains Kicad project files and gerber to build PCBs using 1.8mm LEDs.

This PCB uses charlieplexing to reduce the number of wires. It is possible to build a block signal, input signal, or output signal with this PCB. I designed my own wiring path to avoid using the POV effect to light multiple LEDs. Each situation for each signal is a simple combination of HIGH and LOW signals on all 4 pins.

It's possible to reduce the number of wires for the "Block Signal" (only 2 wires required) and the "Entry Signal" (only 3 wires required). See [documentation/] (documentation/)

I also need a special breadboard version to ease tests. This version allows soldering of resistors.

The gerber.zip files are enough to build the PCB from a manufacturer such as jlcpcb. See [release/] (release/) directory.

History

The version 2 is smaller than the version 1. It solves the "shunting signal" Hp0 + Sh1 did not work because the right white LED did not light up.

This v3 is a better version as it fixes a distributed current problem.

Source

The [source/] directory contains Kicad files

BOM:

• a PCB per signal. I ordered mine 0.8mm thickness from jlcpcb.com simply by uploading the gerber.zip file.
• 2 to 4 60 to 100 ohm resistors 1/4 W from everywhere
• 1.8mm LEDs. I bought mine from aliexpress.com.