ESP32 Internet of Things (IoT) Weather Station

Introduction to IoT Weather Stations

An IoT weather station is a system designed to measure various environmental parameters such as temperature, humidity, and atmospheric pressure. These measurements are collected by sensors, and the data is transmitted over the internet to a cloud service, where it can be visualized and analyzed. The ESP32, with its built-in Wi-Fi capabilities, makes it an ideal platform for building IoT-based weather stations.

Components of an IoT Weather Station

In this project, we will use the ESP32 to interface with environmental sensors such as a DHT22 (temperature and humidity sensor) and a BMP180 (barometric pressure sensor). The ESP32 will send the sensor data to a cloud platform using MQTT for real-time monitoring and analysis.

  • Set up the ESP32 development environment in Arduino IDE and install necessary libraries (e.g., DHT, Adafruit BMP180).
  • Connect the DHT22 sensor to the ESP32 to measure temperature and humidity.
  • Connect the BMP180 sensor to the ESP32 to measure atmospheric pressure.
  • Set up an MQTT broker (e.g., ThingSpeak or any cloud platform) to receive and display data from the ESP32.
  • Write code to read data from the sensors and send it to the MQTT broker.
  • Visualize the data on the cloud platform and monitor the readings in real-time.

Formula: Pressure = Standard Pressure + (Temperature × (Height / 1000))

Components Required

  • 1 × ESP32 Development Board
  • 1 × DHT22 Temperature and Humidity Sensor
  • 1 × BMP180 Barometric Pressure Sensor
  • 1 × Breadboard and Jumper Wires
  • 1 × Power Supply (e.g., 5V USB power adapter)
  • 1 × MQTT Broker (e.g., ThingSpeak, Adafruit IO)
  • 1 × Cloud Platform Account (e.g., ThingSpeak, Blynk)

Pin Configuration

  • GPIO 21 (DHT22 Data Pin): Data pin of the DHT22 sensor connected to GPIO 21 of the ESP32.
  • GPIO 22 (BMP180 SDA Pin): SDA pin of the BMP180 sensor connected to GPIO 22 of the ESP32.
  • GPIO 23 (BMP180 SCL Pin): SCL pin of the BMP180 sensor connected to GPIO 23 of the ESP32.

Make sure to power the sensors with the correct voltage. The DHT22 sensor requires a 3.3V supply, while the BMP180 operates on 3.3V as well.

Wiring and Connections

  • DHT22 VCC -> 3.3V
  • DHT22 GND -> GND
  • DHT22 Data -> GPIO 21
  • BMP180 VCC -> 3.3V
  • BMP180 GND -> GND
  • BMP180 SDA -> GPIO 22
  • BMP180 SCL -> GPIO 23

Code for ESP32 IoT Weather Station

1#include <Wire.h>
2#include <Adafruit_Sensor.h>
3#include <DHT.h>
4#include <Adafruit_BMP085_U.h>
5#include <WiFi.h>
6#include <PubSubClient.h>
7
8#define DHTPIN 21
9#define DHTTYPE DHT22
10DHT dht(DHTPIN, DHTTYPE);
11
12Adafruit_BMP085_Unified bmp;
13
14const char* ssid = "Your_SSID";
15const char* password = "Your_PASSWORD";
16const char* mqtt_server = "mqtt://your_mqtt_broker";
17WiFiClient espClient;
18PubSubClient client(espClient);
19
20void setup() {
21  Serial.begin(115200);
22  WiFi.begin(ssid, password);
23  while (WiFi.status() != WL_CONNECTED) {
24    delay(1000);
25    Serial.println("Connecting to WiFi...");
26  }
27  Serial.println("Connected to WiFi");
28  client.setServer(mqtt_server, 1883);
29  dht.begin();
30  if (!bmp.begin()) {
31    Serial.println("Could not find a valid BMP180 sensor, check wiring!");
32    while (1);
33  }
34}
35
36void loop() {
37  if (!client.connected()) {
38    reconnect();
39  }
40  client.loop();
41
42  float temperature = dht.readTemperature();
43  float humidity = dht.readHumidity();
44  float pressure;
45  bmp.getPressure(&pressure);
46
47  char tempStr[8];
48  char humidityStr[8];
49  char pressureStr[8];
50
51  dtostrf(temperature, 1, 2, tempStr);
52  dtostrf(humidity, 1, 2, humidityStr);
53  dtostrf(pressure, 1, 2, pressureStr);
54
55  client.publish("weather/temperature", tempStr);
56  client.publish("weather/humidity", humidityStr);
57  client.publish("weather/pressure", pressureStr);
58  delay(60000);
59}
60
61void reconnect() {
62  while (!client.connected()) {
63    if (client.connect("ESP32WeatherStation")) {
64      client.subscribe("weather/control");
65    } else {
66      delay(5000);
67    }
68  }
69}

Code Explanation

  • #include <Wire.h>: Includes the necessary libraries for I2C communication between the ESP32 and the sensors.
  • DHT dht(DHTPIN, DHTTYPE);: Initializes the DHT22 sensor on the specified pin.
  • Adafruit_BMP085_Unified bmp;: Initializes the BMP180 sensor to read pressure data.
  • WiFi.begin(ssid, password);: Establishes a Wi-Fi connection with the specified credentials.
  • client.publish("weather/temperature", tempStr);: Publishes the temperature data to the MQTT broker under the topic 'weather/temperature'.

Applications

  • Home automation with weather data integration
  • Real-time weather monitoring for outdoor environments
  • Agricultural IoT systems for monitoring temperature and humidity
  • Smart city applications for environmental monitoring
  • Environmental monitoring in remote or rural areas

Conclusion

This IoT weather station project using the ESP32 demonstrates how to collect environmental data and send it to the cloud for real-time monitoring. By leveraging MQTT and cloud platforms like ThingSpeak or Blynk, you can easily visualize the data and build an interactive weather monitoring system. This project is an excellent starting point for exploring IoT applications in environmental monitoring.