I wanted to measure how many times and for how long my fridge was opened every day.

This device check how many times and for how long you open your door fridge, then every 30 minutes, it sends that data to the IoT platform Adafruit IO.

The device is based in the ESP-01 which is able to connect via wifi to an Internet network. It has a door magnetic sensor. When the door is open, the device increases a counter and gets the ESP-01 clock time. Then after the door is closed, it gets the ESP-01 clock time again and makes a subtraction. That time and the counter are stored in two variables and send every 30 minutes to the Adafruit IO platform.

You can change the interval time between data is sent if you will.

Supplies

ESP8266 ESP-01. https://amzn.to/2RK5W1V
ESP-01 Breadboard Adaptor. https://amzn.to/2KjrTR8
Door magnetic sensor. https://amzn.to/2VAClck
Power Supply 12 VDC 2 A. https://amzn.to/2XNL7pW
Breadboard power supply. https://amzn.to/3bm5hLT
10 KΩ Resistor. https://amzn.to/2VlgMgY
330 Ω Resistor.
Breadboard. https://amzn.to/2Kl1tyk
5 mm Led. https://amzn.to/3a3FoyJ
Breadboard jumpers. https://amzn.to/3eyDUQQ
Breadboard flexible jumpers. https://amzn.to/3eydxdF

Step 1: Have a Hand All Components

Collect all the components that you need to implement this project.

Step 2: Make Connections

Make the connections shown in the schematic.

Be aware about these two things:

GPIO2 pin needs to be high at boot.

Remember ESP-01 works with 3.3V.

Step 3: Upload the Code

The code has two files. In the config.h you set your Adafruit credentials and network configuration like wifi name and password.

// Information about Adafruit IO
// Link:  https://learn.adafruit.com/welcome-to-adafruit-io...
// Adafruit invests time and resources providing this open source code. // Please support Adafruit and open source hardware by purchasing // products from Adafruit! // // Written by Todd Treece for Adafruit Industries // Copyright (c) 2016 Adafruit Industries // Licensed under the MIT license. // // All text above must be included in any redistribution.
//************************** Configuration ***********************************
// In the config.h you should set the Adafruit IO credentials and configure the  // network settings. 
#include "config.h"
//************************ Example Starts Here *******************************
// Variables bool valor; 
int count = 0; 
bool flag = false; 
unsigned long previo; 
unsigned long actual; 
unsigned long tiempo; 
unsigned long ttotal = 0; 
unsigned long intervalo = 1000;
unsigned long duracion = 0; 
const int puerta = 2; // GPIO2 
const int led = 0; // GPIO0
// set up the feeds 
AdafruitIO_Feed *tempo = io.feed("tempo"); 
AdafruitIO_Feed *cuenta = io.feed("cuenta");
void setup() {
  // start the serial connection   
  Serial.begin(115200);
  
  pinMode(puerta, INPUT);   
  pinMode(led, OUTPUT);   
  pinMode(led_conteo, OUTPUT);   
  pinMode(led_puerta, OUTPUT);
  // wait for serial monitor to open   
  while(! Serial);
  // connect to io.adafruit.com   
  Serial.print("Connecting to Adafruit IO");  
  io.connect();
  // wait for a connection    
  while(io.status() < AIO_CONNECTED) {     
  Serial.print(".");     
   delay(500);   }
  // we are connected   
  Serial.println();   
  Serial.println(io.statusText());
  
}
void loop() {
  // io.run(); is required for all sketches.  
  // it should always be present at the top of your loop  
  // function. it keeps the client connected to  
  // io.adafruit.com, and processes any incoming data.   
  io.run();
  digitalWrite(led, LOW);
  valor = digitalRead(puerta); // Read the sensor. If the door is close valor = High or true. If the door is open valor = low or false.
  
  if (valor == false & flag == false) {         
      delay(200);
      valor = digitalRead(puerta);               
      if (valor == false){       
          count++;            // Increase the opening counter      
          flag = true;       
          previo = millis();  // Get the time at that moment              }   
           }          
  if (valor == true & flag == true) {         
      delay(200);
      valor = digitalRead(puerta);
      if (valor == true){       
          flag = false;      
          actual = millis();  // Get the time at that moment.           
  // Increase the time variable after the door was closed.          
  if (actual - previo > intervalo){         
      tiempo = actual - previo;
      tiempo = tiempo/1000;  // Change time from miliseconds to seconds.
      ttotal = tiempo + ttotal;  // Add time to the total timer.        
       }                     
    }     
  }         
 duracion++; // increase by one the duracion variable   
 delay(400);   
  
 if (duracion > 3800){    //Set time between data sending.
    // Show the variable ttotal in the serial monitor and send it to Adafruit     
    Serial.print("sending -> ");     
    Serial.println(ttotal);     
    tempo->save(ttotal);
    // Show the variable count in the serial monitor and send it to Adafruit    
    Serial.print("sending -> ");      
    Serial.println(count);     
    cuenta->save(count);          
    // Reset variables    
    duracion = 0;     
     ttotal = 0;     
     count = 0;
     digitalWrite(led, HIGH);  // turn on the light to show sending data
  delay(1000); //Delay 1 second       
 } 
}

Step 4: Set Adafruit IO

You should open an account on Adafruit IO. After that, you need to know how it works.

Check the link below to know about Adafruit IO, there you know how you can use Adafruit the credentials, how set the feeds and how configure the dashboards.

https://learn.adafruit.com/welcome-to-adafruit-io/overview