Graphical simulation of the Enigma Machine which runs on an Arduino+Adafruit touchscreen
Enigma Visual version 1.3 dated 03/10/2019 @2110 written by Mark J Culross, KD5RXT (kd5rxt@arrl.net)
HARDWARE:
This project runs on an Arduino Uno or equivalent. For me personally, I prefer the SparkFun RedBoard - Programmed with Arduino (DEV-13975) - https://www.sparkfun.com/products/13975
For the visual (graphical) version of the Enigma machine, this project uses the Adafruit 2.8" TFT Touch Shield for Arduino with Resistive Touch Screen (1651) - https://www.adafruit.com/product/1651
This particular display provides touchscreen input & 320x240 full color display using the Adafruit Touch Shield V2 library.
DISPLAY CALIBRATION:
The coordinates returned from the touchscreen will vary slightly from unit to unit, so if you find that the point where you touch on the screen is not matching the point where the Enigma Visual Simulator program responds, then you should run the TFTcal-Adafruit.ino calibration sketch. Doing so will help to determine the touchpad scaling constants TS_MINX, TS_MINY, TS_MAXX, & TS_MAXY on-the-fly which will work best for your particular hardware. NOTE: use something small but not too sharp (e.g. a toothpick) to poke the touchscreen during calibration.
IMPLEMENTATION:
The design of the encode/decode processing in this sketch is based upon the original encode/decode engine from the EnigmaSerial.ino sketch (w/ some cleanup, optimization, & enhancements, all w/ no apparent adverse effects on equivalent/correct operation)
My primary goal for this project was simulate as many versions of the Enigma machine as I could, with the ability to verify correct operations for each. All versions of the Enigma machine that are simulated were verified to operate correctly using the excellent/versatile HTML-code utility titled "Universal Enigma Simulator v2.0" by Daniel Palloks, available at the following URL: http://people.physik.hu-berlin.de/~palloks/js/enigma/index_en.html
Verification of correct operations for each of the machines was facilitated by using the sample Enigma settings & messages available at the following URL: http://franklinheath.co.uk
COMPILER/LIBRARY NOTE:
If this version is built using older versions of the IDE and/or some versions of the Adafruit TFT library, the resulting compiled code could exceed the available program space of an Arduino Uno. When this version is built with IDE version 1.8.7, the resulting code is efficient enough that it fits within the available program space. If you find that the build process reports that the available program space is exceeded, then simply comment out the line "#define SERIAL_MODE", essentially removing the calls for run-time serial input & output, which should thus avoid exceeding the available program space until the IDE and/or Adafruit TFT library can be updated to newer versions. Of course, doing so also results in the loss of the otherwise available serial capabiltity for processing Enigma messages & the ability to display the intricate details of the internal mechanical operations of the Enigma machine over the serial port.
CONTACT INFO:
If you have any questions, suggestions for improvement, and most especially any bug reports, please contact me at kd5rxt@arrl.net.
OVERVIEW VIDEO:
For a quick & dirty overview, see the following video: https://youtu.be/8nu2KaLVWrU
OPERATION:
See the "Operation.txt" file for detailed operating instructions.
VERIFICATION:
See the "Enigma_Sample_Messages.txt" file for sample Enigma messages which can be used to verify correct operation of the Enigma Visual Simulator.