Arduino Uno + ESP8266 12E + Blynk + Relay

Question

I started adventure with arduino and programming 2 months ago.So, I am new in this topics. Until now I realized few projects including Blynk connected with arduino. The last one was similar to one described in topic but I used the ENC28j60 instead of ESP8266 module and then it worked fine.

The problem started with ESP module.

Short description of project:

The main idea is to control AC light with Blynk App support. First of all I made a connection according to picture below: As power source I used the USB phone charger connected with step by voltage converter to get in final the 3.3V source. I additionally connected the Arduino Uno with relay module like this:

Arduino ====> Relay module

5V ====> VCC

GND ====> GND

Pin 5 ====> IN1

Everythink you can see in pictures below (sorry for quality)

And for now I did almost every step (with so many problems). Here I mean: 1. I checked if arduino is connected with ESP module by serial port -> system report "ready" status. 2. I upload the below (template) Arduino IDE sketch for my project:

#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[] = "***";

// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "***";
char pass[] = "***";



void setup()
{
  // Debug console--
  Serial.begin(9600);

  Blynk.begin(auth, ssid, pass);

}

void loop()
{
  Blynk.run();

}

And finally I started the New project in Blynk. I set the Arduino uno as a hardware model and WiFi as connection type. Then I added the Button and set the Output to D5.

And now (close to the end of project) I met with a problem. After pushing the connect button (in up-right corner) I receive the information that device is connected (Online). Then when I try to push the button to Active Relay - nothing happens. Whats more. I tried with different pins on Arduino with the same results. And I don't know why (probably because I have still small knowladge) but when I set the Button output value to D2 - after connection when I push it then the diode on ESP module Turn OFF and Turn ON. I tried to find solution on this forum and in many other places for last 3 days but without any results. That's why I decided to ask You for help. Do you know what did I wrong or what should I add to project to make connection between the Blynk and relay work correct?

Write if you will need some more or detailed information from my side.

Answer 1

Why are you using both the uno and the esp? You can just use the esp instead of the combo, will make your project less power hungry and smaller. If you wonder about using just the esp, you can use the nodemcu boards (which can be found for less that 4€ per unit in China).

I've some example sketches for this (with temperature and humidity), if you want to take a look at those.

Answer 2

When looking at the pictures and code you have postet, it seems that you have flashed the ESP with a Arduino sketch. This is fine if you would like to activate the relay directly with the ESP (without the Arduino UNO). Then you just have to connect the relay to the ESP instead of to the Arduino. Unfortunately not all relay boards can operate with the 3.3V logic that the ESP supplies, but maybe you'r lucky.

On the other hand, if you would like to use the Arduino UNO with the ESP as Wi-Fi, then you would have to reflash the ESP with the original AT firmware. Then you could connect it to the Arduino and use a sketch that looks something like this.

#define BLYNK_PRINT Serial

#include <ESP8266_Lib.h>
#include <BlynkSimpleShieldEsp8266.h>

char auth[] = "YourAuthToken";

char ssid[] = "YourNetworkName";
char pass[] = "YourPassword";

#include <SoftwareSerial.h>
SoftwareSerial EspSerial(2, 3); 
// pin 3 connected to ESP RX and pin 2 connected to ESP TX

// Your ESP8266 baud rate:
#define ESP8266_BAUD 115200

ESP8266 wifi(&EspSerial);

void setup()
{
  // Debug console
  Serial.begin(9600);

  delay(10);

  // Set ESP8266 baud rate
  EspSerial.begin(ESP8266_BAUD);
  delay(10);

  Blynk.begin(auth, wifi, ssid, pass);
}

void loop()
{
  Blynk.run();
}

And you should remove the connection between RST and GND on the Arduino