BIMEcamp2017_morse.ino

#include <string.h>
const char *letter = "**ETIANMSURWDKGOHVF?L?PJBXCYZQ??";
int letterlen = strlen(letter);
const char *want = "FOOT";
char morse[1000];
int morses = 0;

const int light = 5;
const int beepin = 6;
void setup()
{
    pinMode(light, OUTPUT);
    pinMode(beepin, OUTPUT);
    // decode
    int wantlen = strlen(want);
    for(int i=wantlen-1; i>=0; --i){
        int where = 0;
        for(where=0; where < letterlen; ++where)
            if(want[i] == letter[where])
                break;
//        if(where == letterlen)
//            printf("NO");
        while( letter[where] != '*'){
            morse[morses++] = where & 1 ? '-' : '.';
            where >>= 1;
        }
        if(i)
            morse[morses++] = ' ';
    }
    // reversed
    for(int i=0; i<morses/2; ++i){
        char t = morse[i];
        morse[i] = morse[morses-1-i];
        morse[morses-1-i] = t;
    }
    morse[morses++] = '\0';
}

void beep(unsigned char delayms){
  analogWrite(beepin, 40);      // Almost any value can be used except 0 and 255
                           // experiment to get the best tone
  delay(delayms);          // wait for a delayms ms
  analogWrite(beepin, 0);       // 0 turns it off
  delay(delayms);          // wait for a delayms ms   
}  

void loop()
{
    const int timeunit = 500;
    for(int i=0; i<morses; i++) {
        if(morse[i] == '-') {
            digitalWrite(light, HIGH);
            delay(timeunit * 3);
            digitalWrite(light, LOW);
            delay(timeunit);
        }
        else if(morse[i] == '.') {
            digitalWrite(light, HIGH);
            delay(timeunit);
            digitalWrite(light, LOW);
            delay(timeunit);
        }
        else {
            beep(200);
            delay(timeunit * 3);
        }

    }
}