This repository contains the Arduino code for the S&T GeoTronics M4 Enigma. The S&T GeoTronics M4 Enigma is an Arduino Mega custom shield programmed to replicate the behavior of a German M4 Enigma machine. It consistes of 4 16-Segment units, 5 LEDs, 26 Lamps setup as keyboard, 26 keyboard buttons & 10 Function keys. The 115 light emitting diodes are multi-plexed. This minimizes the amount of pins needed to control them down to 38 pins and all 36 pushbuttons keys are sharing a total of 4 pins.

Depending on your type of kit, you need to install the relevant version of the code onto the Arduino:

• Open Enigma M4
• Open Enigma M4 with Plugboard

To understand how to operate the S&T GeoTronics M4 Enigma, please refer to the following guide:

• BJ Gleason - Open Enigma for Dummies

• Designed, assembled & programmed by Marc Tessier & James Sanderson 20/9/13.
• Modified for Prototype PCB pair on 4/12/13.
• Modified to obey doublesteping and have M3 function 22/3/14.