Morse code on a ThinkPad sleep status LED

morse.c

/*
	Original code by Matthew Herbst - Last updated 7/21/2013

  ThinkPad adaptation by nikp123 - 28/12/2023
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>

#include <unistd.h>

// Morse Code Timings - change as desired
const double   MULTIPLIER    = 2.5; //Increase durations of dots/dashes
const uint32_t DOT           = (uint32_t) 92.3 * MULTIPLIER; //1 dot
const uint32_t DASH          = (uint32_t) 276.9 * MULTIPLIER; //3 dots
const uint32_t TIMING_SPACE  = (uint32_t) 92.3 * MULTIPLIER; //1 dot: space between dots/dashes
const uint32_t CHAR_SPACE    = (uint32_t) 276.9 * MULTIPLIER; //3 dots: space between characters
const uint32_t WORD_SPACE    = (uint32_t) 646.1; //7 dots - space between words

// Morse Code timings holder array setup
#define NUM_CHARS           96
#define MORSE_MAX_CHAR_SIZE 7

// Array placement is based on a character's ASCII value
// IF YOU ADD A NEW VALUE BE SURE TO ADD IT TO THE ACCEPTED CHAR ERROR CHECK
// Note: since there is no difference between lower/upper case in Morse, 
// only upper is entered here - lower case is converted to upper using ASCII
static const uint32_t TIMINGS[NUM_CHARS][MORSE_MAX_CHAR_SIZE] = {
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, 
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0},
	{DASH, DOT, DASH, DOT, DASH, DASH, 0}, //!
	{DOT, DASH, DOT, DOT, DASH, DOT, 0}, //"
	{0, 0, 0, 0, 0, 0, 0},
	{DOT, DOT, DOT, DASH, DOT, DOT, DASH}, //$
	{0, 0, 0, 0, 0, 0, 0},
	{DOT, DASH, DOT, DOT, DOT, 0, 0}, //&
	{DOT, DASH, DASH, DASH, DASH, DOT, 0}, //'
	{DASH, DOT, DASH, DASH, DOT, 0, 0}, //(
	{DASH, DOT, DASH, DASH, DOT, DASH, 0}, //)
	{0, 0, 0, 0, 0, 0, 0},
	{DOT, DASH, DOT, DASH, DOT, 0, 0}, //+
	{DASH, DASH, DOT, DOT, DASH, DASH, 0}, //,
	{DASH, DOT, DOT, DOT, DOT, DASH, 0}, //-
	{DOT, DASH, DOT, DASH, DOT, DASH, 0}, //.
	{DASH, DOT, DOT, DASH, DOT, 0, 0}, ///
	{DASH, DASH, DASH, DASH, DASH, 0, 0}, //0
	{DOT, DASH, DASH, DASH, DASH, 0, 0}, //1
	{DOT, DOT, DASH, DASH, DASH, 0, 0}, //2
	{DOT, DOT, DOT, DASH, DASH, 0, 0}, //3
	{DOT, DOT, DOT, DOT, DASH, 0, 0}, //4
	{DOT, DOT, DOT, DOT, DOT, 0, 0}, //5
	{DASH, DOT, DOT, DOT, DOT, 0, 0}, //6
	{DASH, DASH, DOT, DOT, DOT, 0, 0}, //7
	{DASH, DASH, DASH, DOT, DOT, 0, 0}, //8
	{DASH, DASH, DASH, DASH, DOT, 0, 0}, //9
	{DASH, DASH, DASH, DOT, DOT, DOT, 0}, //:
	{DASH, DOT, DASH, DOT, DASH, DOT, 0}, //;
	{0, 0, 0, 0, 0, 0, 0},
	{DASH, DOT, DOT, DOT, DASH, 0, 0}, //=
	{0, 0, 0, 0, 0, 0, 0},
	{DOT, DOT, DASH, DASH, DOT, DOT, 0}, //?
	{DOT, DASH, DASH, DOT, DASH, DOT, 0}, //@
	{DOT, DASH, 0, 0, 0, 0, 0}, //A
	{DASH, DOT, DOT, DOT, 0, 0, 0}, //B
	{DASH, DOT, DASH, DOT, 0, 0, 0}, //C
	{DASH, DOT, DOT, 0, 0, 0, 0}, //D
	{DOT, 0, 0, 0, 0, 0, 0}, //E
	{DOT, DOT, DASH, DOT, 0, 0, 0}, //F
	{DASH, DASH, DOT, 0, 0, 0, 0}, //G
	{DOT, DOT, DOT, DOT, 0, 0, 0}, //H
	{DOT, DOT, 0, 0, 0, 0, 0}, //I
	{DOT, DASH, DASH, DASH, 0, 0, 0}, //J
	{DASH, DOT, DASH, 0, 0, 0, 0}, //K
	{DOT, DASH, DOT, DOT, 0, 0, 0}, //L
	{DASH, DASH, 0, 0, 0, 0, 0}, //M
	{DASH, DOT, 0, 0, 0, 0, 0}, //N
	{DASH, DASH, DASH, 0, 0, 0, 0}, //O
	{DOT, DASH, DASH, DOT, 0, 0, 0}, //P
	{DASH, DASH, DOT, DASH, 0, 0, 0}, //Q
	{DOT, DASH, DOT, 0, 0, 0, 0}, //R
	{DOT, DOT, DOT, 0, 0, 0, 0}, //S
	{DASH, 0, 0, 0, 0, 0, 0}, //T
	{DOT, DOT, DASH, 0, 0, 0, 0}, //U
	{DOT, DOT, DOT, DASH, 0, 0, 0}, //V
	{DOT, DASH, DASH, 0, 0, 0, 0}, //W
	{DASH, DOT, DOT, DASH, 0, 0, 0}, //X
	{DASH, DOT, DASH, DASH, 0, 0, 0}, //Y
	{DASH, DASH, DOT, DOT, 0, 0, 0}, //Z
	{0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0},
	{0, 0, 0, 0, 0, 0, 0},
	{DOT, DOT, DASH, DASH, DOT, DASH, 0}, //_
};

void delay(uint32_t msec) {
  usleep(msec * 1000);
}

void ledWrite(uint8_t val) {
  FILE *fp = fopen("/sys/class/leds/tpacpi::lid_logo_dot/brightness", "ab");
  if(fp == NULL) {
    fprintf(stderr, "Failed to open ThinkPad LED diode :)\n");
    return;
  }

  fprintf(fp, "%hhu", val);
  fclose(fp);
}

// The loop routine runs in an infinite loop:
int main(int argc, char *argv[]) {
  if(argc == 1) {
    fprintf(stderr, "no message supplied. exiting...\n");
  }

  // Read the user input
  const int messages = argc;

  // Display the user input back to the user
  fprintf(stderr, "Displaying:");
  for(int i = 1; i < argc; i++) {
    fprintf(stderr, " %s", argv[i]);

    for(int j = 0; j < strlen(argv[i]); j++) {
      // Get the ASCII value of the character being looked at
      int ASCII = argv[i][j];

      // Convert lower case letters to upper case
      if(ASCII >= 97 && ASCII <= 122) {
        ASCII = ASCII - 32;
      }

      // Ensure the character is one that has been programmed in for Morse
      if((ASCII >= 32 && ASCII <= 34) || ASCII == 36 || 
         (ASCII >= 38 && ASCII <= 41) || (ASCII >= 43 && ASCII <= 59) ||
         ASCII == 61 || (ASCII >= 63 && ASCII <= 90) || ASCII == 95) {      
        // If the character is a space
        if(ASCII == 32) {
          delay(WORD_SPACE);
        } else {
          // Go through the timing sequence for each character
          for(int k = 0; k < MORSE_MAX_CHAR_SIZE; ++k) { 
            // If the timing sequence is over, break the loop
            if(TIMINGS[ASCII][k] == 0) {
              break;
            } else { // Display the timing sequence on the LED
              ledWrite(1);
              delay(TIMINGS[ASCII][k]);
              ledWrite(0);
              delay(TIMING_SPACE);
            }
          } 
        }  
      } else {
        fprintf(stderr, "'%c' does not have a Morse Code timing. Skipping it.\n", argv[i][j]);
      }
      delay(CHAR_SPACE);
    }
  }
  fprintf(stderr, "\n");
}