webthing-arduino

A simple server for the ESP8266, the ESP32, or any WiFi101-compatible board that implements Mozilla's proposed Web of Things API. The LED example exposes an onOffSwitch named "Built-in LED" which controls the board's built-in LED. The LED Lamp example ups the ante by introducing a level property to expose a dimmableLight.

Arduino

ESP8266 or ESP32

To run on either of these boards, download the Arduino IDE and set it up for board-specific development. These Adafruit guides explain how to set up for an ESP8266 and how to set up for an ESP32. You will also need to download the ESP Async WebServer library and unpack it in your sketchbook's libraries folder.

WiFi101

Install the WiFi101 library from the Arduino library manager.

Continuing onwards

Make sure to install the ArduinoJson library if you don't have it installed already. Note that you must select ArduinoJson version 5, not the prerelease beta version 6.

Next, download this library from the same library manager by searching for webthing.

You should be able to upload the example sketch onto your board and use it as a simple Web Thing. This Web Thing can be talked to using the WoT API or added to the Mozilla IoT Gateway using the "Add Thing by URL" feature. Note that right now WiFi101-based Things must be manually added through typing the full URL to the Web Thing, e.g. http://192.168.0.103/things/led.

If you want to create a Web Thing from scratch, make sure to include both "Thing.h" and "WebThingAdapter.h". You can then add Things and Properties to your board using our proposed API.

PlatformIO

Add the webthing-arduino library through PlatformIO's package management interface. You may also need to manually add the ArduinoJson and other libraries to your project.

Example

#include <Arduino.h>
#include "Thing.h"
#include "WebThingAdapter.h"

const char* ssid = "public";
const char* password = "";

#if defined(LED_BUILTIN)
const int ledPin = LED_BUILTIN;
#else
const int ledPin = 13;  // manually configure LED pin
#endif

WebThingAdapter* adapter;

const char* ledTypes[] = {"OnOffSwitch", "Light", nullptr};
ThingDevice led("led", "Built-in LED", ledTypes);
ThingProperty ledOn("on", "", BOOLEAN, "OnOffProperty");

bool lastOn = false;

void setup(void){
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, HIGH);
  Serial.begin(115200);
  Serial.println("");
  Serial.print("Connecting to \"");
  Serial.print(ssid);
  Serial.println("\"");
#if defined(ESP8266) || defined(ESP32)
  WiFi.mode(WIFI_STA);
#endif
  WiFi.begin(ssid, password);
  Serial.println("");

  // Wait for connection
  bool blink = true;
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
    digitalWrite(ledPin, blink ? LOW : HIGH); // active low led
    blink = !blink;
  }
  digitalWrite(ledPin, HIGH); // active low led

  Serial.println("");
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
  adapter = new WebThingAdapter("w25", WiFi.localIP());

  led.addProperty(&ledOn);
  adapter->addDevice(&led);
  adapter->begin();
  Serial.println("HTTP server started");
  Serial.print("http://");
  Serial.print(WiFi.localIP());
  Serial.print("/things/");
  Serial.println(led.id);
}

void loop(void){
  adapter->update();
  bool on = ledOn.getValue().boolean;
  digitalWrite(ledPin, on ? LOW : HIGH); // active low led
  if (on != lastOn) {
    Serial.print(led.id);
    Serial.print(": ");
    Serial.println(on);
  }
  lastOn = on;
}