Devspace Arduino

Arduino library for connecting ESP32 devices to the Devspace IoT platform over MQTT.

This repository is the working copy for the public devspace-arduino library. It is intentionally small for v0.1: connect WiFi, connect MQTT with Devspace device credentials, publish device status, and send sensor readings.

Supported Boards

• ESP32 with the Arduino framework

Devspace itself is MQTT-based, so other boards can connect through the raw MQTT contract. This official Arduino library v0.1 is currently tested with ESP32. ESP8266 support is intentionally outside the v0.1 library scope.

Board Package

Install the Arduino board package that matches your hardware.

For the current ESP32_DHT11 example, install:

• esp32 by Espressif Systems

Dependencies

Install these libraries from Arduino Library Manager:

• PubSubClient by Nick O'Leary
• ArduinoJson by Benoit Blanchon

The ESP32_DHT11 example also needs:

• DHT sensor library by Adafruit
• Adafruit Unified Sensor

When installing this library from a GitHub ZIP, Arduino IDE may not install dependencies automatically. Install the dependencies above manually before compiling the examples.

Install Locally

During development, copy or symlink this folder into your Arduino libraries directory:

~/Documents/Arduino/libraries/Devspace

The folder should contain library.properties, src/, and examples/ at the top level.

Quick Start

Create a device and sensors in Devspace first, then copy the generated MQTT credentials and sensor IDs into an example sketch.

#include <Devspace.h>

Devspace devspace;

const char* WIFI_SSID = "your-wifi";
const char* WIFI_PASSWORD = "your-password";

const char* MQTT_BROKER = "mqtt.devspace.id";
const uint16_t MQTT_PORT = 1883;
const char* MQTT_CLIENT_ID = "devspace_xxxxxxxxxxxx";
const char* MQTT_USERNAME = "mqtt_xxxxxxxxxxxx";
const char* MQTT_PASSWORD = "generated-password";

const char* SENSOR_ID = "sensor-uuid-from-dashboard";

unsigned long lastSend = 0;

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

  devspace.begin(
    WIFI_SSID,
    WIFI_PASSWORD,
    MQTT_BROKER,
    MQTT_PORT,
    MQTT_CLIENT_ID,
    MQTT_USERNAME,
    MQTT_PASSWORD
  );
}

void loop() {
  devspace.loop();

  if (devspace.connected() && millis() - lastSend >= 5000) {
    lastSend = millis();
    devspace.sendData(SENSOR_ID, 25.5);
  }
}

Broker Host

For production Devspace, use the same MQTT host shown in the dashboard:

const char* MQTT_BROKER = "mqtt.devspace.id";
const uint16_t MQTT_PORT = 1883;

For local Devspace, replace MQTT_BROKER with your laptop/server LAN IP, for example:

const char* MQTT_BROKER = "192.168.1.100";
const uint16_t MQTT_PORT = 1883;

Do not use localhost from ESP32 firmware. On the ESP32, localhost means the ESP32 itself.

API

bool begin(
  const char* wifiSSID,
  const char* wifiPassword,
  const char* mqttBroker,
  uint16_t mqttPort,
  const char* mqttClientId,
  const char* mqttUsername,
  const char* mqttPassword
);

void loop();
bool connected();
bool sendData(const char* sensorId, double value);
bool sendData(const char* sensorId, double value, const char* timestamp);
bool publishStatus(const char* status);
void setDebug(bool enabled);
void setReconnectInterval(unsigned long intervalMs);
void setWiFiConnectTimeout(unsigned long timeoutMs);
int mqttState();

MQTT Contract

The library builds Devspace topics from mqttClientId:

• Data: devspace/{mqttClientId}/data
• Status: devspace/{mqttClientId}/status

Sensor data is published with retained = false. Status messages are published with retained = true, and the MQTT Last Will message is set to offline.

See docs/mqtt-contract.md for the raw MQTT contract.

Examples

• BasicPublish: sends a dummy value every 5 seconds.
• ESP32_DHT11: reads DHT11 temperature and humidity, then sends each reading as a separate Devspace sensor data message.

Versioning

This library uses SemVer. Public API changes should be reflected in CHANGELOG.md.