Published March 11, 2017

ESP8266 Blynk Bridge: Simple Device-to-Device Communication

Learn how to get started with Blynk Bridge — the easiest way to enable communication between multiple devices like ESP8266, Arduino, or Rasp

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ESP8266 Blynk Bridge: Simple Device-to-Device Communication

Things used in this project

Hardware components

Espressif ESP8266 ESP-01

Arduino UNO

Raspberry Pi 2 Model B

Software apps and online services

Blynk

Story

Project Summary:
This project shows how to use Blynk Bridge to enable simple communication between two ESP8266 boards — perfect for IoT setups that require device-to-device messaging without a local server. With just a few lines of code and the Blynk app, you can start sending data between devices in no time.

Quick Steps Overview:

Install Blynk Library – Add the Blynk library to your Arduino IDE.

Install Blynk Library – Add the Blynk library to your Arduino IDE.

Create a Blynk Project – Set up two devices in the Blynk app and get their Auth Tokens.

Create a Blynk Project – Set up two devices in the Blynk app and get their Auth Tokens.

Configure Blynk Bridge – Use the WidgetBridge class in one ESP8266 to send virtual writes to the other.

Configure Blynk Bridge – Use the WidgetBridge class in one ESP8266 to send virtual writes to the other.

Upload the Code – Flash each ESP8266 with the appropriate sender/receiver sketch.

Upload the Code – Flash each ESP8266 with the appropriate sender/receiver sketch.

Test the Communication – Use buttons or sensors to trigger messages from one device to the other in real-time.

Test the Communication – Use buttons or sensors to trigger messages from one device to the other in real-time.

For the full tutorial with code examples and detailed setup, visit Blynk Bridge: Another Way to Communicate Between Two ESP8266.

/**************************************************************
   Blynk Bridge - Communication between ESP8266
   Sketch code for the receiver module (module which is controlled)
   www.geekstips.com
 **************************************************************/
 
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
 
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "xxxxxxxxxxxxxxxxxxxxxxxxxxxx";
 
// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "XXXXXXXX";
char pass[] = "********";
 
// This code will update the virtual port 5
BLYNK_WRITE(V5) {
  int pinData = param.asInt();
}
 
void setup(){
  Serial.begin(9600);
  Blynk.begin(auth, ssid, pass);
}
 
void loop(){
  Blynk.run();
}

/**************************************************************
   Blynk Bridge - Communication between ESP8266
   Sketch code for the master module (module which will command others)
   www.geekstips.com
 **************************************************************/
#define BLYNK_PRINT Serial
 
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h>
#include <DHT.h>
 
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "xxxxxxxxxxxxxxxxxxxxxxxxxxxx";
 
// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "XXXXXXXXXXXXX";
char pass[] = "*************";
 
#define DHTPIN 2 // What digital pin we're connected to
 
//#define DHTTYPE DHT11   // DHT 11
  #define DHTTYPE DHT22   // DHT 22, AM2302, AM2321
//#define DHTTYPE DHT21   // DHT 21, AM2301
 
DHT dht(DHTPIN, DHTTYPE);
SimpleTimer timer;
WidgetBridge bridge1(V1);
 
BLYNK_CONNECTED() {
  // Place the AuthToken of the second hardware here
  bridge1.setAuthToken("tttttttttttttttttttttttttttttttt"); 
}
 
void sendSensor(){
  // get readings from the DHT22 sensor
  float h = dht.readHumidity();
  float t = dht.readTemperature(); // or dht.readTemperature(true) for Fahrenheit
  
  if (isnan(h) || isnan(t)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
 
  // Send command to the second ESP
  // WHEN Temperature IS OVER 28 C
  // in order to open the 220V Relay
  // Also update the VIRTUAL port 5 
  // on the second ESP
  if(t > 28){
     bridge1.digitalWrite(2, 1000);
     bridge1.virtualWrite(V5, 1000); 
  }else{
     bridge1.digitalWrite(2, 0);
     bridge1.virtualWrite(V5, 0); 
  }
 
  // Send temperature and humidity to Blynk App
  // on VIRTUAL ports 5 and 6 in order to 
  // display on Gauge Widget
  Blynk.virtualWrite(V5, h);
  Blynk.virtualWrite(V6, t);
}
 
void setup(){
  Serial.begin(9600);
  Blynk.begin(auth, ssid, pass);
  dht.begin();
 
  timer.setInterval(1000L, sendSensor);
}
 
void loop(){
  Blynk.run();
  timer.run();
}