Serial Comunication between Arduinos – With Wire & Wireless

— please check an updated code sample on the following post —
http://lab.guilhermemartins.net/2013/08/01/new-basic-arduino-serial-communication/

 

I´ve created this example to make two Arduinos talk in a simple and clear fashion.
You will see below an example with wires, and another one without wires.

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Setup with TX and RX pins connected by wire:

On the sender Arduino there is a potenciometer, the values are read and sent through the serial port.
On the receiver Arduino one Led intensity will change accordingly the pot value.

Tx on Arduino#1 -> connect to ->  Rx  on Arduino#2
Rx on Arduino#1 -> connect to ->  Tx on Arduino#2

NOTE:
Don´t forget to disconnect Tx / Rx wires before upload

// SENDER

int analogValue5, val5;

void setup() {
// Serial port enable
Serial.begin(19200);
}

void loop() {
// read analog pin 5
analogValue5 = analogRead(5);

// remap values from the analogValue5 variable to 0 / 255
val5 = map(analogValue5, 0, 1023, 0, 255);

// send the value to the serial port
Serial.println(val5, BYTE);

}

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// RECIEVER

byte incomingByte;

void setup() {
// Serial port enable
Serial.begin(19200);

// declare pin 11 as output, this is the LED
pinMode (11, OUTPUT);
}

void loop() {

// if there is bytes available coming from the serial port
if (Serial.available()) {

// set the values to the ‘incomingByte’ variable
incomingByte = Serial.read();

// write the value to the pin 11
analogWrite(11, int(incomingByte));

}
}


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Wireless setup with XBee modules:

Recently I got two XBee modules, and here is the setup to make them talk to each other:
As a start I used 2 potenciometers to control the intensity of two LEDs and It works pretty well.  :]

I´m using this adapters to connect the XBee to the circuit. They are very simple to assemble and to use.

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// SENDER

int analogValue2, analogValue5, val2, val5;

void setup()
{
// start serial port at 19200 bps
Serial.begin(19200);
}

void loop()
{
// read analog input
analogValue2 = analogRead(2);
analogValue5 = analogRead(5);

// remap values

val2 = map(analogValue2, 0, 1023, 253, 0);  // 254 and 255 for SYNC
val5 = map(analogValue5, 0, 1023, 253, 0);

Serial.print(254, BYTE); //SYNC char
Serial.print(val2, BYTE);

Serial.print(255, BYTE); //SYNC char
Serial.print(val5, BYTE);

delay(150);
}

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// RECIEVER

byte incomingByte, sensor1, sensor2;

void setup() {

// start serial port at 19200 bps
Serial.begin(19200);
Serial.println(“Ready!”);

// led pins

pinMode (5, OUTPUT);
pinMode (6, OUTPUT);

delay(1000);

}

void loop() {
if (Serial.available()) {   // are there any bytes available on the serial port ???

// assign bytes to the var ‘incomingByte’
incomingByte = Serial.read();

Serial.print(int(incomingByte));

// from now on is pretty clear I guess   :)

if ((int(incomingByte) == 254)) {
sensor1 = Serial.read();
Serial.print(“Sensor 1 = “);
Serial.print(int(sensor1));
}

if ((int(incomingByte) == 255)) {
sensor2 = Serial.read();
Serial.print(“  Sensor 2 = “);
Serial.print(int(sensor2));
}
}

analogWrite (5, sensor1);
analogWrite (6, sensor2);
}

80 thoughts on “Serial Comunication between Arduinos – With Wire & Wireless”

  1. serial comm takes both digital pins 0 and 1, they must be free in order to be able to upload code to the arduino.
    you will notice if you ever use anything connected to those pins ;)

  2. thanx a lot ….all those answers are very much usefulllll….again thanx for the help i ll implement it soon

  3. every time I try to upload the reciver code it gives me error ( stray ‘/’ in program ) please help

  4. following serial reading in rx

    ?HÌz;X?HÌz;X?HÌz;X?HÌz;X?HÌz;X?HÌz;X?HÌz;X?HÌz;X?HÌz;X?HÌz;X:H?HÌz;X?HÌ

  5. i like the way the problem is solver..
    is it possible to simoultanouslt send all 6 analog read values via serial instead of 2.
    and receive correctly..
    can u pls help me with the code..
    thanks

  6. hello sir……..
    i want the details abut how to interface3arduinos……..coz i need to transmitt an array of data through GSM interfaced with arduino

  7. Thank you soooo much your example code was unspeakably useful. I appreciate you taking the time to post about your project, it will save me hours of research!

  8. I can’t understand because it doesn’t work: the receiving code stamp on serialmonitor the ascii caracter converted like: 505352505351505353505348505352505351505353505348505352505351505353505348505352505351505353

    So the LED doesn’t turn ON

  9. Hi! why the code ‘BYTE’ wrong and the warning :

    “As of Arduino 1.0, the ‘BYTE’ keyword is no longer supported. Please use Serial.write() instead.”

    how to solve the problem?
    thanks

  10. I got warning :
    “As of Arduino 1.0, the ‘BYTE’ keyword is no longer supported. Please use Serial.write() instead.”

    how to solve it?
    thanks

  11. Hello, how much for a Code that can send analog readings from accelerometer and aslo 4 push buttons and recibe these data to another xbee with arduino ?

  12. hello Hector, apologize but I won’t have the time to make this code for you, have a look on the arduino forums, I’m sure you will find what you need
    good luck

  13. No xbee configuration is necessary ? just wire these things and they are ready to go ?

  14. I want to establish a communication between ping sensors(ultrasonic dist. sensors) and xbee.
    the ping sensor transmits a signal and the xbee receives it and instructs another ping sensor(which is attached to this xbee) to transmit a signal to the first ping sensor.

  15. I never connected a sensor directly to the xbee module.
    Sincerely hope you find a way and if you dare, share it here with the rest of us ;)

  16. I want to transmit analog sensor data wirelessly using Arduino. Will it be possible using the Xbee??

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