Instructions | Arduino Teletype

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#include<Serial.h>
//Baudot lookup table
unsigned char lookup[] = {
' ', 'E', ' ', 'A', ' ', 'S', 'I', 'U',
'\n', 'D', 'R', 'J', 'N', 'F', 'C', 'K',
'T', 'Z', 'L', 'W', 'H', 'Y', 'P', 'Q',
'O', 'B', 'G', 0, 'M', 'X', 'V', 0,
' ', '3', '\n', '-', ' ', '`', '8', '7',
'\r', ' ', '4', '\'', ',', '!', ':', '(',
'5', '+', ')', '2', '$', '6', '0', '1',
'9', '?', '&', 0, '.', '/', ';', 0 };
const int RELAY_PIN = 4;
const int CHAR_DELAY = 22; //milliseconds
const int START_BIT_DELAY = 22; // milliseconds
const int STOP_BIT_DELAY = 44; // milliseconds
const int SPACE = 4;
const int F_SHIFT = 27;
const int L_SHIFT = 31;
const int CR = 8;
const int LF = 2;
boolean letters_on = true;
boolean print_debug = false;
/* transmits 5 bit integers */
void byte_send(int _byte){
send_start_bit();
// loop through all 5 bits and send a space for zero bits, and mark for one bits.
for(int _bit = 0; _bit < 5; _bit++){
switch (bitRead(_byte,_bit)) {
case 0:
Serial.print(0);
space();
break;
case 1:
Serial.print(1);
mark();
break;
} // end switch
} // end for loop
send_stop_bit();
} // end byte_send()
/* Lookup and decode characters before transmitting. */
void char_send(char letter){
char l = toupper(letter);
Serial.print("sending ");
Serial.print(l);
int idx = lookupChar(l);
Serial.print(" idx: ");
Serial.print(idx);
Serial.print(" Binary: ");
// check for offset
if (31 < idx){ // shift for figures
if (letters_on){
figure_shift();
}
idx = idx - 32;
} else { // shift for letters
if (false == letters_on){
letter_shift();
}
}
byte_send(idx);
Serial.println();
} // end char_send()
void letter_shift(){
Serial.print(" [L_SHIFT] ");
letters_on = true;
byte_send(L_SHIFT);
}
void figure_shift(){
Serial.print(" [F_SHIFT] ");
letters_on = false;
byte_send(F_SHIFT);
}
void cr(){ Serial.print(" <CR> "); byte_send(CR); }
void lf(){ Serial.print(" <LF>"); byte_send(LF); }
void send_start_bit(){
digitalWrite(RELAY_PIN, HIGH);
delay(START_BIT_DELAY);
}
void send_stop_bit(){
digitalWrite(RELAY_PIN, LOW);
delay(STOP_BIT_DELAY);
}
void mark(){
digitalWrite(RELAY_PIN, LOW);
delay(CHAR_DELAY);
}
void space(){
digitalWrite(RELAY_PIN, HIGH);
delay(CHAR_DELAY);
}
int lookupChar(char letter){
if (' ' == letter){ return 4; }
for (int lookupIdx = 0; lookupIdx < sizeof(lookup); lookupIdx++){
if (letter == lookup[lookupIdx]){
return lookupIdx;
}
}
return 0;
}
void setup(){
Serial.begin(115200);
pinMode(RELAY_PIN, OUTPUT);
pinMode(5, OUTPUT);
digitalWrite(RELAY_PIN, LOW);
}
void demo(){
cr();
lf();
letter_shift();
for (int i = 0; i < 34; i++){
char_send('R');
char_send('Y');
}
}
void demo2(){
int idx = 0;
char demo_string[] = "THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG'S BACK 1234567890 TIMES";
cr();
lf();
letter_shift();
for (int i = 0; i < sizeof(demo_string); i++){
char_send(demo_string[i]);
}
}
void demo3(){
int cur = 0;
while (cur < 68) {
if (Serial.available() > 0) {
Serial.print(cur);
Serial.print(": ");
char_send(Serial.read());
cur++;
}
}
cr();
lf();
}
void loop() {
demo();
demo2();
//demo3();
}