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ESP32 Setup

ESP32 Setup Guide

Section titled “ESP32 Setup Guide”

Connect your ESP32 microcontroller to SiliconWit.IO using MQTT.

Requirements

Section titled “Requirements”
  • ESP32 development board
  • Arduino IDE or PlatformIO
  • WiFi network
  • SiliconWit.IO account with a registered device

Arduino IDE Setup

Section titled “Arduino IDE Setup”

Install ESP32 Board Support

Section titled “Install ESP32 Board Support”
  1. Open Arduino IDE
  2. Go to File → Preferences
  3. Add to “Additional Board Manager URLs”: 
    https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
  4. Go to Tools → Board → Boards Manager
  5. Search for “esp32” and install

Install Required Libraries

Section titled “Install Required Libraries”

Install these libraries via Sketch → Include Library → Manage Libraries:

  • PubSubClient - MQTT client library
  • ArduinoJson - JSON parsing (optional but recommended)

Basic Connection Example

Section titled “Basic Connection Example”
#include <WiFi.h>
#include <PubSubClient.h>


// WiFi credentials
const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";


// SiliconWit.IO MQTT settings
const char* mqtt_server = "mqtt.siliconwit.io";
const int mqtt_port = 1883;
const char* device_id = "YOUR_DEVICE_ID";
const char* access_token = "YOUR_ACCESS_TOKEN";


WiFiClient espClient;
PubSubClient client(espClient);


void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);


  WiFi.begin(ssid, password);


  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }


  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}


void reconnect() {
  while (!client.connected()) {
    Serial.print("Connecting to MQTT...");


    if (client.connect(device_id, device_id, access_token)) {
      Serial.println("connected");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" retrying in 5 seconds");
      delay(5000);
    }
  }
}


void setup() {
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, mqtt_port);
}


void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();


  // Send data every 10 seconds
  static unsigned long lastMsg = 0;
  if (millis() - lastMsg > 10000) {
    lastMsg = millis();


    // Create JSON payload
    String payload = "{\"temperature\":25.5,\"humidity\":60}";


    // Publish to telemetry topic
    String topic = "devices/" + String(device_id) + "/telemetry";
    client.publish(topic.c_str(), payload.c_str());


    Serial.println("Data sent: " + payload);
  }
}

Secure Connection (TLS)

Section titled “Secure Connection (TLS)”

For production, use TLS encryption:

#include <WiFiClientSecure.h>


WiFiClientSecure espClient;
PubSubClient client(espClient);


void setup() {
  // ... WiFi setup ...


  espClient.setInsecure(); // For testing only
  // For production, use: espClient.setCACert(root_ca);


  client.setServer(mqtt_server, 8883); // TLS port
}

With DHT Temperature Sensor

Section titled “With DHT Temperature Sensor”
#include <WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>


#define DHTPIN 4
#define DHTTYPE DHT22


DHT dht(DHTPIN, DHTTYPE);


// ... WiFi and MQTT setup ...


void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();


  static unsigned long lastMsg = 0;
  if (millis() - lastMsg > 30000) {
    lastMsg = millis();


    float temp = dht.readTemperature();
    float hum = dht.readHumidity();


    if (!isnan(temp) && !isnan(hum)) {
      String payload = "{\"temperature\":" + String(temp) +
                       ",\"humidity\":" + String(hum) + "}";


      String topic = "devices/" + String(device_id) + "/telemetry";
      client.publish(topic.c_str(), payload.c_str());
    }
  }
}

Deep Sleep for Battery Power

Section titled “Deep Sleep for Battery Power”
#define uS_TO_S_FACTOR 1000000
#define TIME_TO_SLEEP 300  // 5 minutes


void setup() {
  Serial.begin(115200);


  setup_wifi();
  client.setServer(mqtt_server, mqtt_port);


  if (client.connect(device_id, device_id, access_token)) {
    // Read and send data
    String payload = "{\"temperature\":25.5}";
    String topic = "devices/" + String(device_id) + "/telemetry";
    client.publish(topic.c_str(), payload.c_str());


    delay(100); // Allow message to send
    client.disconnect();
  }


  // Go to sleep
  esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR);
  esp_deep_sleep_start();
}


void loop() {
  // Never reached
}

Troubleshooting

Section titled “Troubleshooting”

Connection Issues

Section titled “Connection Issues”
ProblemSolution
WiFi won’t connectCheck SSID/password, ensure 2.4GHz network
MQTT connection failsVerify device ID and access token
Messages not appearingCheck topic format matches dashboard

Debug Output

Section titled “Debug Output”

Enable verbose logging:

Serial.setDebugOutput(true);

Next Steps

Section titled “Next Steps”