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ESP32 Setup Guide

Connect your ESP32 microcontroller to SiliconWit.io using MQTT.

Requirements

Section titled “Requirements”

Create Your Device on SiliconWit.io

Section titled “Create Your Device on SiliconWit.io”
  1. Log in to siliconwit.io and go to Devices → Add Device
  2. Choose a template or click Start from scratch
  3. Fill in:
    • Device Name: e.g., “ESP32 Sensor”
    • Device Type: Sensor
    • Data Interval: 10 seconds (for testing)
  4. In the Data Fields section, click Import and paste:
[
  { "name": "temperature", "label": "Temperature", "unit": "°C" },
  { "name": "humidity", "label": "Humidity", "unit": "%" }
]
  1. Click Validate, then Import
  2. Click Create Device
  3. Copy your Device ID (format: SWD-XXXXXX) and Access Token from the device page

See the Field Schema guide for nested fields, roles, and more examples.

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 <WiFiClientSecure.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 = 8883;
const char* device_id = "SWD-XXXXXX";        // Replace with your Device ID
const char* access_token = "your-access-token"; // Replace with your Access Token


WiFiClientSecure 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();
  espClient.setInsecure(); // For testing - use setCACert() in production
  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 = "d/" + String(device_id) + "/t";
    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 = "d/" + String(device_id) + "/t";
      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 = "d/" + String(device_id) + "/t";
    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”