Wi-Fi Implementation: ESP32 using REST API for Cloud Services

To implement Wi-Fi communication on an ESP32, using REST API to send real-time sensor data to cloud services like ThingSpeak, AWS, or Firebase.

Benefits

• Fast data transfer
• Easy REST API integration
• Real-time monitoring via cloud

Required Hardware

• ESP32 Development Board
• Wi-Fi Network
• Cloud Service (e.g., ThingSpeak, Firebase, AWS)
• (Optional) Sensors (e.g., DHT11, Temperature, Humidity)

Steps

1. Set Up Cloud Services

   Create ThingSpeak or Firebase account and obtain API keys/URLs.

2. Install Required Libraries

   Install WiFi.h, HTTPClient.h, and optionally ArduinoJson via Arduino Library Manager.

3. Configure Wi-Fi and API Keys
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   1const char* ssid = "your_wifi_ssid";
   2const char* password = "your_wifi_password";
   3const String writeAPIKey = "your_thingspeak_write_api_key";
   4const String firebaseURL = "https://your-project-id.firebaseio.com/";

4. Wi-Fi Connection Setup
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   1#include <WiFi.h>
   2#include <HTTPClient.h>
   3
   4void setup() {
   5  WiFi.begin(ssid, password);
   6  while (WiFi.status() != WL_CONNECTED) delay(1000);
   7}

5. Send Data to ThingSpeak
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   1void loop() {
   2  if (WiFi.status() == WL_CONNECTED) {
   3    HTTPClient http;
   4    float sensorData = 25.5;
   5    String url = "http://api.thingspeak.com/update?api_key=" + writeAPIKey + "&field1=" + String(sensorData);
   6    http.begin(url);
   7    int httpResponseCode = http.GET();
   8    http.end();
   9    delay(20000);
   10  }
   11}

6. Send Data to Firebase (Optional)
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   1void sendToFirebase(float sensorData) {
   2  HTTPClient http;
   3  String jsonData = "{"temperature": " + String(sensorData) + "}";
   4  http.begin(firebaseURL);
   5  http.addHeader("Content-Type", "application/json");
   6  int httpResponseCode = http.POST(jsonData);
   7  http.end();
   8}

7. Monitor Data on Cloud

   Use ThingSpeak graphs or Firebase Console → Realtime Database to view data.