tinygomorse.go

package main

import (
	"machine"
	"time"
	"unicode"
)

const (
	unit = time.Millisecond * 200
)

var dur = map[rune]time.Duration{
	'.': 1,
	'-': 3,
}

// moreseCode is a the [A-Z] subset of the morse code characters, see
// https://en.wikipedia.org/wiki/Morse_code#Letters,_numbers,_punctuation,_prosigns_for_Morse_code_and_non-Latin_variants
var morseCodes = map[rune]string{
	'A': ".-",
	'B': "-...",
	'C': "-.-.",
	'D': "-..",
	'E': ".",
	'F': "..-.",
	'G': "--.",
	'H': "....",
	'I': "..",
	'J': ".---",
	'K': "-.-",
	'L': ".-..",
	'M': "--",
	'N': "-.",
	'O': "---",
	'P': ".--.",
	'Q': "--.-",
	'R': ".-.",
	'S': "...",
	'T': "-",
	'U': "..-",
	'V': "...-",
	'W': ".--",
	'X': "-..-",
	'Y': "-.--",
	'Z': "--..",
}

func main() {
	machine.LED.Configure(machine.PinConfig{Mode: machine.PinOutput})
	input := "hello world"
	for _, r := range input {
		blinkMorseCode(r)
	}
}

// blinkMorseCode translates a character in [a-zA-Z ] to Morse code following the
// International Morse code (https://en.wikipedia.org/wiki/Morse_code#Representation,_timing,_and_speeds):
//
//  	short mark, dot or dit (  ▄ ): "dit duration" is one time unit long
//      long mark, dash or dah (  ▄▄▄ ): three time units long
//      inter-element gap between the dits and dahs within a character: one dot duration or one unit long
//      short gap (between letters): three time units long
//      medium gap (between words): seven time units long
func blinkMorseCode(r rune) {
	if unicode.IsSpace(r) {
		time.Sleep(4 * unit) // We have already slept 3 units at the end of the last morseCode.
		return
	}

	morseCode := morseCodes[unicode.ToUpper(r)]
	for _, r := range morseCode {
		machine.LED.High()
		time.Sleep(dur[r] * unit)
		machine.LED.Low()
		time.Sleep(unit)
	}
	time.Sleep(2 * unit) // We have already slept 1 unit at the end of the last dot/dash. 
}