Erwan's Blog

Why go for such an arduino when the Uno and Nano are available?
First because it is much smaller, then because it also uses much less power (due to the missing FTDI chip).

The pro mini can be found here for about 6 € : http://dx.com/p/178183 .
The usb dongle can be found here for about 2 € : http://dx.com/p/149859 .

Below the wiring. As mentionned, since the usb dongle does not have a reset feature, press reset on the arduino right between the compiling and uploading part in the Arduino Gui.

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In the Arduino Gui, dont forget to select the right card i.e « arduino pro or pro mini 5v / 16 mhz / atmega328).

Voila!

Erwan

I wanted to find a way to call my kids, with me sitting on ground floor and them, sitting on the top floor of the house.

2 arduino, one acting as transmitter, one acting as receiver and here we go : they would not ignore me anymore 🙂

Lets start the transmitter (schema and code) : it has a push button to send the signal and a led to indicate it is transmitting.

#include 

const int led_pin = 11;
//const int transmit_pin = 4;
//const int transmit_en_pin = 3;
const int transmit_pin = 3;
//const int transmit_en_pin = 3;
const int buttonPin=2;


void setup()
{

   pinMode(buttonPin, INPUT);        // sets the digital pin as output
  pinMode(led_pin, OUTPUT);      // sets the digital pin as output
      delay(1000);
    Serial.begin(9600);	// Debugging only
    Serial.println("setup");
  // Initialise the IO and ISR
  vw_set_tx_pin(transmit_pin);
  //vw_set_rx_pin(receive_pin);
  //vw_set_ptt_pin(transmit_en_pin);
  //vw_set_ptt_inverted(true); // Required for DR3100
  vw_set_ptt_inverted(false); 
  vw_setup(2400);	 // Bits per sec
}

byte count = 1;

void loop()
{
  int reading = digitalRead(buttonPin);
  if(reading==HIGH) {
   //
  digitalWrite(led_pin, HIGH); // Flash a light to show transmitting
 char msg[7] = {'h','e','l','l','o',' ','#'};
 //msg[5]=count;
  vw_send((uint8_t *)msg, strlen(msg)+1);
  vw_wait_tx(); // Wait until the whole message is gone
  Serial.println(count);
  count = count + 1;
  delay(500);
  digitalWrite(led_pin, LOW);
  }
}

Next comes the receiver : it has a buzzer playing a small melody and a led blinking to indicate it is receiving.

#include 
#include 

const int led_pin = 8;
const int receive_pin = 3; //2
const int buzzer=11;

// tableau de mémorisation des notes de la mélodie
int melody[] = { NOTE_C4, NOTE_G3,NOTE_G3, NOTE_A3, NOTE_G3,0, NOTE_B3, NOTE_C4};

// tableau de mémorisation de la durée des notes : 4 = noire, 8 = croche, etc.:
int noteDurations[] = {4, 8, 8, 4,4,4,4,4 };
  
  void play(){
    // boucle pour parcourir les notes de la mélodie
  for (int thisNote = 0; thisNote < 8; thisNote++) { // thisNote de 0 à 7 

    // pour calculer la durée de la note, on divise 1 seconde par le type de la note
    //ainsi noire = 1000 / 4 sec, croche = 1000/8 sec, etc...
    int noteDuration = 1000/noteDurations[thisNote];

    // joue la note sur la broche x pendant la durée voulue
    tone(buzzer, melody[thisNote],noteDuration);

    // pour distinguer les notes, laisser une pause entre elles
    // la durée de la note + 30% fonctionne bien :
    int pauseBetweenNotes = noteDuration * 1.30;
    delay(pauseBetweenNotes); // delai entre les notes

    // stoppe la production de son sur la broche 8 :
    noTone(buzzer);
  }
  }

void setup()
{
   pinMode(led_pin, OUTPUT);        // sets the digital pin as output
  pinMode(buzzer, OUTPUT);      // sets the digital pin as output
    delay(1000);
    Serial.begin(9600);	// Debugging only
    Serial.println("setup");

    // Initialise the IO and ISR
    //vw_set_tx_pin(transmit_pin);
    vw_set_rx_pin(receive_pin);
    //vw_set_ptt_pin(transmit_en_pin);
    //vw_set_ptt_inverted(true); // Required for DR3100
    vw_set_ptt_inverted(false); 
    vw_setup(2400);	 // Bits per sec
    vw_rx_start();       // Start the receiver PLL running
}

void loop()
{
    uint8_t buf[VW_MAX_MESSAGE_LEN];
    uint8_t buflen = VW_MAX_MESSAGE_LEN;

    if (vw_get_message(buf, &buflen)) // Non-blocking
    {
	int i;

        
	// Message with a good checksum received, print it.
	Serial.print("Got: ");
	
	for (i = 0; i < buflen; i++)
	{
	    Serial.print(buf[i], HEX);
	    Serial.print(' ');
	}
        Serial.print(' ');
        for (i = 0; i < buflen; i++)
	{
	    Serial.print(char(buf[i]));
	    Serial.print(' ');
	}
	Serial.println();
        digitalWrite(led_pin, HIGH);delay(1500);digitalWrite(led_pin, LOW);delay(1500);
        digitalWrite(led_pin, HIGH);delay(1500);digitalWrite(led_pin, LOW);delay(1500);       
        play();
    }
}

Voila !

Last time we have seen how to use an arduino and a 16*2 lcd screen.
Now lets see to use an arduino and a tvout to a small display screen (2.5 inches) using a RCA connector.

First the wiring

Then the code

#include 

TVout TV;
unsigned char x, y;

void setup ( )
{
  TV.start_render( _PAL );
}

void loop ( )
{
  TV.clear_screen ( );
  TV.print_str ( 10, 10, "Hello World!!!" );
  TV.delay ( 60 );
}

TvOut lib can be found here

And finally a picture