Project 3 SOS light

1. Project instruction

SOS is a Morse code distress signal (▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄), used internationally, that was originally established for maritime use. In formal notation SOS is written with an overscore line, to indicate that the Morse code equivalents for the individual letters of “SOS” are transmitted as an unbroken sequence of three dots / three dashes / three dots, with no spaces between the letters.[1] In International Morse Code three dots form the letter “S” and three dashes make the letter “O”, so “S O S” became a common way to remember the order of the dots and dashes. (IWB, VZE, 3B, and V7 form equivalent sequences, but traditionally SOS is the easiest to remember.)

2. Project Principle

We could produce a letter through LED on and off state, long and short flash respectively represent dot and dash. Through Morse code table,“S”is represented by three dots, therefore, we replace three dots with short flash, dash symbolizes letter“O”, replace threw dashes with long flash.

3. Project circuit

4. Project code

/*
keyestudio Max Development Board
Project 3
s o s
http://www.keyestudio.com
*/
int ledPin = 10;

void setup() 
{
 pinMode(ledPin, OUTPUT);
}

void loop() 
{
        //  stand for“ S”with three quick flash
       for(int x=0;x<3;x++)
       {
               digitalWrite(ledPin,HIGH);            //set LED on
               delay(150);                           //delay in 150ms
               digitalWrite(ledPin,LOW);             //set LED off
               delay(100);                           //delay 100ms
       }
               // time gap to produce next letter
        delay(100);
 
         //stand for“ O”with three short flash
         for(int x=0;x<3;x++)
         {
                digitalWrite(ledPin,HIGH);            //set LED on
                delay(400);                           //delay in 400ms
                digitalWrite(ledPin,LOW);             //set LED off
                delay(100);                           //delay in 100ms
          }
 
          // time gap to produce next letter
          delay(100);
 
          // stand for“ S”with three quick flash
          for(int x=0;x<3;x++)
          {
                  digitalWrite(ledPin,HIGH);            //set LED on 
                  delay(150);                           //delay in 150ms
                  digitalWrite(ledPin,LOW);             //set LED off
                  delay(100);                           //delay in 100ms
            }
 
           // wait 5s before repeating S.0.S signal 
           delay(5000);
}

Upload code to Arduino, we will view LED flash S.O.S signal and wait for 5s and flash again. Plug external power in Arduino, and place them in a waterproof box, then S.O.S signal can be sent.

S.O.S signal is usually applied in maritime use and mountain-climbing.