Post DHT 11 Data with Push Button

In this project, you will use the Antares Shield Workshop on the ESP8266 module. In this Antares Shield Workshop, there are temperature, humidity (DHT11), relay, LED and push button sensors. You will monitor the temperature and humidity with a push button as a trigger sender.

Prerequisites

The materials required follow the General Prerequisites on the previous page. If you have not prepared the requirements on that page, then you can visit the following page.

The additional materials specific to this project are as follows.

Shield Workshop Antares
Antares ESP HTTP Library. This documentation uses the Antares ESP HTTP library version 1.4.0.

If you have not installed Antares ESP HTTP 1.4.0, please follow these steps.

Antares Wi-Fi HTTP

DHT11 Library. This documentation uses DHT11 Sensor Library version 1.4.4.

If you have not installed the DHT11 Sensor Library version 1.4.4. you can follow the steps in the following link.

DHT11 Sensor Library

Follow These Steps

1. Launch the Arduino IDE application

2. Opening Sample Programme

You can open the programme code in the Arduino IDE via File > Example > Antares ESP HTTP > ESP8266-Simple-Project > POST_DATA_DHT11_PUSHBUTTON.

Here is the programme code of the example POST_DATA_DHT11_PUSHBUTTON

#include <AntaresESPHTTP.h>  // Include the AntaresESP2866HTTP library for connecting to the Antares platform
#include "DHT.h"             // Include the DHT sensor library

#define DHTPIN D1      // Define the pin number for the DHT sensor (connected to pin D1)
#define DHTTYPE DHT11  // Define the DHT sensor type as DHT11

#define ACCESSKEY "YOUR-ACCESS-KEY"    // Replace with your Antares account access key
#define WIFISSID "YOUR-WIFI-SSID"      // Replace with your Wi-Fi SSID
#define PASSWORD "YOUR-WIFI-PASSWORD"  // Replace with your Wi-Fi password

#define projectName "YOUR-APPLICATION-NAME"  // Replace with the Antares application name that was created
#define deviceName "YOUR-DEVICE-NAME"        // Replace with the Antares device name that was created

AntaresESPHTTP antares(ACCESSKEY);  // Create an AntaresESP2866HTTP object to interact with Antares
DHT dht(DHTPIN, DHTTYPE);           // Create a DHT object for the DHT sensor

#define pushButtonPin A0  // Define the pin number for the push button (connected to pin 32)
#define ledPin D2         // Define the pin number for the LED (connected to pin 12)

bool ledState = false;         // Variable to store the state of the LED (ON or OFF)
bool lastButtonState = false;  // Variable to store the previous state of the push button

void setup() {
  Serial.begin(115200);    // Initialize serial communication with baudrate 115200
  antares.setDebug(true);  // Enable debug mode for AntaresESP32HTTP (messages will be displayed in the serial monitor)

  // Reset WiFi cache before connecting
  WiFi.disconnect();

  antares.wifiConnection(WIFISSID, PASSWORD);  // Connect to Wi-Fi with the specified SSID and password
  dht.begin();                                 // Initialize the DHT sensor

  pinMode(pushButtonPin, INPUT);  // Set the push button pin as input with internal pull-up resistor
  pinMode(ledPin, OUTPUT);        // Set the LED pin as output
  digitalWrite(ledPin, LOW);      // Turn off the LED initially
}

void loop() {
  // Read the current state of the push button
  int analogValue = analogRead(A0);
  bool currentButtonState = (analogValue < 512);  // Adjust the threshold as needed

  // Check if the button state has changed (button press detected)
  if (currentButtonState != lastButtonState && currentButtonState == LOW) {
    Serial.println("The button is pressed");

    // Toggle state of the LED (ON to OFF or OFF to ON)
    ledState = !ledState;
    digitalWrite(ledPin, ledState);

    // Read temperature and humidity from the DHT sensor
    float hum = dht.readHumidity();
    float temp = dht.readTemperature();

    // Check if the sensor reading is valid
    if (isnan(hum) || isnan(temp)) {
      Serial.println("Failed to read DHT sensor!");
      return;
    }

    // Print temperature and humidity values to the serial monitor
    Serial.println("Temperature: " + (String)temp + " *C");
    Serial.println("Humidity: " + (String)hum + " %");

    // Add temperature and humidity data to the Antares storage buffer
    antares.add("temperature", temp);
    antares.add("humidity", hum);

    // Send the data from the storage buffer to Antares
    antares.send(projectName, deviceName);

    // Add some delay to avoid multiple data sending due to button debouncing
    delay(1000);
  }

  // Update the last button state for the next iteration
  lastButtonState = currentButtonState;
}

3. Set WiFi Credential and Antares Credential in Program Code

Change the HTTP Protocol parameters in the following variables *ACCESSKEY, *WIFISSID, *PASSWORD, *projectName, and *deviceName. Adjust to the parameters in the Antares console.

#define ACCESSKEY "YOUR-ACCESS-KEY"    // Replace with your Antares account access key
#define WIFISSID "YOUR-WIFI-SSID"      // Replace with your Wi-Fi SSID
#define PASSWORD "YOUR-WIFI-PASSWORD"  // Replace with your Wi-Fi password

#define projectName "YOUR-APPLICATION-NAME"  // Replace with the Antares application name that was created
#define deviceName "YOUR-DEVICE-NAME"        // Replace with the Antares device name that was created

The *Access key parameter is obtained from your Antares account page.

The WIFISSID parameter is obtained from the name of the Wifi / Hotspot that is currently being used by you. for example in the image below.

The *PASSWORD parameter is obtained from the WiFi password you are currently using.

The parameters *projectName and *deviceName are obtained from the Application Name and Device Name that have been created in the Antares account.

4. Compile and Upload Program

Connect ESP 8266 WEMOS D1R2 with your computer and make sure the Communication Port is read.

On Windows operating systems, the check can be done via Device Manager. If your ESP 8266 WEMOS D1R2 is read, the USB-Serial CH340 appears with the port adjusting the port availability (in this case it reads COM4).

Set up the ESP8266 WEMOS D1R2 board by clicking Tools > Board > esp8266 in the Arduino IDE, then make sure the one used is LOLIN (WEMOS) D1 R2 & mini. Select the port according to the communication port that is read (in this case COM4). The result will look like the following picture.

After all the setup is complete, upload the programme by pressing the arrow icon as shown below. Wait for the compile and upload process to finish.

The Tick icon on the Arduino IDE is just the verify process. Usually used to compile the programme to find out if there are errors or not. The arrow icon on the Arduino IDE is the verify and upload process. Usually used to compile the programme as well as flash the programme on the target board.

If the programme upload is successful, it will look like the following image.

After uploading the programme, you can view the serial monitor to debug the programme. The serial monitor icon is shown in the following image.

Set the serial baud rate to 115200 and select BothNL & CR. The result will look like the following image.

Make sure the serial baud rate matches the value defined in the programme code. If the serial baud rate is not the same between the programme code and the serial monitor, the ASCII characters will not be read properly.