Morse decoder and password checker

Forum 2005-2010 (read only) General Exhibition
2

I've seen a few people posting code, so here's mine. I'd use the "format for forum" but it's throwing an exception. I blame the structure of my code, which is very much programming by accident.

It's messy, but it (mostly) works. I'm posting the current state as an inspiration for others.

/*

  • Morse Code Decoder and door opener
  • Josh Myer josh@joshisanerd.com
  • 20090103 rev 0 -- ugly and unfortunate, but mostly functional (my first arduino code)
  • Hook a debounced switch up to digital pin 2, like you would for the Button demo.
  • This code reads morse code from digital02, turning it into ASCII characters.
  • If you key in "SOS" (... --- ...), it will turn on the LED on digital13.
  • The intended application is to let me key in a password at my apartment's
  • front gate and have it automatically let me into the building, instead of
  • fumbling around for keys.
  • There's still lots of stuff to do and clean up, but I wanted to share the idea
  • and the current implementation to help spur people on.
    */

#include <avr/pgmspace.h>
#include <string.h>

int ledPin = 13; // choose the pin for the LED
int inputPin = 2; // choose the input pin (for a pushbutton)
int val = 0; // variable for reading the pin status

#define THRESHOLD 3
#define DELAY_TIME 10 // ms

int n_since_zero = 0;
int n_in_zero = 0;

#define NCHARS 26+10+3

char morse_chars[NCHARS] = {
'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',
'0',
'1',
'2',
'3',
'4',
'5',
'6',
'7',
'8',
'9',
'.',
',',
'?',

};

char* morse_strings[NCHARS] = {
".-",
"-...",
"-.-.",
"-..",
".",
"..-.",
"--.",
"....",
"..",
".---",
"-.-",
".-..",
"--",
"-.",
"---",
".--.",
"--.-",
".-.",
"...",
"-",
"..-",
"...-",
".--",
"-..-",
"-.--",
"--..",
"-----",
".----",
"..---",
"...--",
"....-",
".....",
"-....",
"--...",
"---..",
"----.",
".-.-.-",
"--..--",
"..--..",
};

#define PAUSE 0
#define DIT 1
#define DAH 2
#define DDLEN 5

char passwd[] = "SOS";

char chars_rx[10];
int char_cursor= 0;

int ditsdahs[DDLEN];
int dd_cursor = 0;

void setup() {
pinMode(ledPin, OUTPUT); // declare LED as output
pinMode(inputPin, INPUT); // declare pushbutton as input

for (int i = 0; i < DDLEN; i++) {
ditsdahs = 0;

  • }*
  • dd_cursor = 0;*
  • for (int i = 0; i < 10; i++) {*
    chars_rx = 0;
    * }*
    * char_cursor = 0;
    _     Serial.begin(9600);_
    _    }_
    void dd_print() {
    _     Serial.print(" > DD BUF: ");_
    _     for(int i = 0; i < DDLEN; i++) {_
    _ Serial.print(ditsdahs);
     Serial.print(", ");
     }
     Serial.println();
    }_
    boolean dd_eq(charbuf) {
    * if(ditsdahs[0] == PAUSE) return false;*
    * int i;*
    _ for(i = 0; ditsdahs != PAUSE && i < DDLEN; i++) {
    if (ditsdahs == DIT && buf == '-') {
    * return false;
    }
    if (ditsdahs == DAH && buf == '.') {
    return false;
    }
    }
    /
    * Serial.print("Got to the end of ");
    Serial.print(buf);
    Serial.print("; checking strlen=");
    Serial.print(strlen(buf));
    Serial.print(" == i=");
    Serial.println(i);
    /
    if (i != strlen(buf)) return false;
    * return true;
    }
    void dd_decode() {
    for(int i = 0; i < NCHARS; i++) {
    /
    * Serial.print("dd_decode: check i=");*
    * Serial.print(i);
    Serial.print(" , string="");_
    Serial.print(morse_strings);
    _ Serial.print("", c=");_
    Serial.print(morse_chars);
    _ Serial.println();
    /_
    if (dd_eq(morse_strings)) {
    char c = morse_chars*;
    char_emit(c);
    _ break;
    }
    }
    for (int i = 0; i < DDLEN; i++) {
    ditsdahs = 0;
    }_
    dd_cursor = 0;
    _}
    void check_passwd() {
    Serial.print("Check password: ");_
    Serial.print(chars_rx);
    _ Serial.println();_
    if (0 != strstr(chars_rx, passwd)) {
    _ digitalWrite(ledPin, HIGH);
    }
    /
    * for (int i = 0; i < 10; i++) {
    chars_rx = 0;
    }_
    char_cursor = 0;
    _ /
    }
    void char_emit(char c) {
    * Serial.print("Got a char: c=");
    Serial.println(c);_
    chars_rx[char_cursor] = c;
    char_cursor++;
    if (char_cursor >= strlen(passwd)) {
    check_passwd();
    _ }
    }_
    void dd_emit(int v) {
    ditsdahs[dd_cursor] = v;
    dd_cursor++;
    dd_print();
    _ if (v == PAUSE)_
    dd_decode();
    _}
    void dit() {_
    dd_emit(DIT);
    _ Serial.println("DIT");
    }
    void dah() {_
    dd_emit(DAH);
    _ Serial.println("DAH");
    }
    void pause() {_
    dd_emit(PAUSE);
    _ Serial.println("PAUSE");
    }
    void loop(){
    val = digitalRead(inputPin); // read input value*
    * if (val == LOW) {_
    if (n_since_zero > 5) {
    _ / Serial.print("CROSS LOW AFTER ");
    * Serial.println(n_since_zero);*
    /_
    if (n_since_zero > 16) {
    _ dah();
    }
    else {
    dit();
    }
    }_
    n_since_zero = 0;
    n_in_zero++;
    _ }
    else {_
    n_since_zero++;
    _ }_
    if (n_in_zero == 20) {
    _ pause();
    }_
    if (n_since_zero > THRESHOLD) {
    if (n_in_zero > 0) {
    _ // Serial.print("CROSS HIGH AFTER ");
    //Serial.print(" > ");_
    // Serial.println(n_in_zero);
    _ // Serial.println("**************************");
    }_
    n_in_zero = 0;
    _ // digitalWrite(ledPin, HIGH);
    }
    else {
    // digitalWrite(ledPin, LOW);
    }_
    delay(DELAY_TIME);
    _}*_