A Hellschreiber library for Arduino

This library will modulate OOK Hellschreiber signal in the desired output pin. Can be used for beacons, telemetry, tests and experimentation.

Supported characters: 0123456789 ABCDEFGHIJKLMNOPQRSTUVWXYZ.-=!:*. Only UPPERCASE letters supported.

See examples/basic/basic.ino sketch example:

#include <Arduino.h>
#include <Hell.h>

// Setup Hell library to work with PIN number 8
Hell hell(8);

// Setup
void setup() {}

// Loop
void loop() {
  // TX
  hell.tx("THIS IS A TEST");

  delay(9000);
}

See extras/testing.md on how you can use test this library with a speaker.

The library is based on lu1aat/cw-arduino-beacon for symbol matching procedure, supported characters: 0123456789 ABCDEFGHIJKLMNOPQRSTUVWXYZ.-=!:*.

This library is maintained by LU1AAT Andres (lu1aat.andres at gmail dot com)

• fldigi Hellschreiber modem: http://www.w1hkj.com/FldigiHelp/feld_hell_page.html
• nonstopsystems HELLSCHREIBER SOFTWARE: https://www.nonstopsystems.com/radio/hellschreiber-software.htm
• AD9851 Hellschreiber Transmitter: https://www.george-smart.co.uk/arduino/arduino_hellschreiber/
• Hellduino: Sending Hellschreiber from an Arduino: https://brainwagon.org/2012/01/11/hellduino-sending-hellschreiber-from-an-arduino/
• Sending hellschreiber from an Arduino –> Helldunio!: http://www.lb3hc.net/archives/1303
• ARDUINO FOR HAM RADIO | Hellschreiber: https://k183.bake-neko.net/ji3bnb/page14.html

• Symbol table: use PROGMEM to the symbol table in flash (program) memory instead of SRAM. This make possible that the code run in small micro-controllers like ATTiny85.
• Constants: Change int definitions to unsigned.
• Documentation: Added documentation about use with Pixie QRP HF transceiver.

• Initial release
• Support for only uppercase letters, numbers and six simbols.