ESP8266 Switch for a Philips Hue Light

A physical switch for a Philips Hue light, built on an ESP8266. It does not pretend to be a Hue accessory: it talks to the Hue bridge the way the Hue protocol describes, so the bridge and the light do exactly what they do for any other switch. It worked, and there is a video of it on YouTube.

How it works

The switch asks the Hue bridge whether a light is on, and then sends the opposite. It does this over the network, with two calls to the bridge:

Afterwards the ESP8266 goes into deep sleep. ESP.deepSleep(0) puts it to sleep until the next reset, so it uses almost no power between two presses, and a press that resets the module starts the next run.

The username is a key that the bridge makes for a program that wants to control it. It is made on the bridge, as described in the Philips Hue developer documentation, and it gives access to the lights, so keep it private.

The sketch

The sketch is version 2.3.3. The values that you have to change are the address of the bridge, the username, the number of the light and your WiFi name and password. The values below are placeholders:

#include <ESP8266WiFi.h>

IPAddress ip(192, 168, 1, 50);        // a fixed address for this switch
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 255, 0);

int light = 1;                        // number of the Hue light to switch
const char hueHubIP[] = "192.168.1.100";        // IP address of the Hue bridge
const char hueUsername[] = "YOUR_HUE_USERNAME"; // username made on the bridge
const int hueHubPort = 80;
const char ssid[] = "SSID";
const char pass[] = "password";

boolean onOffState = false;           // state of the light, as reported by the bridge
WiFiClient client;

void getHue() {                       // ask the bridge if the light is on
  if (client.connect(hueHubIP, hueHubPort)) {
    client.print("GET /api/"); client.print(hueUsername);
    client.print("/lights/"); client.print(light);
    client.println(" HTTP/1.1");
    client.print("Host: "); client.println(hueHubIP);
    client.println("Content-type: application/json");
    client.println("keep-alive");
    client.println();
    while (client.connected()) {
      if (client.available()) {
        client.findUntil(""on":", "");
        onOffState = (client.readStringUntil(',') == "true");
        break;
      }
    }
    client.stop();
  }
}

void setHue(String command) {         // send a new state to the light
  if (client.connect(hueHubIP, hueHubPort)) {
    client.print("PUT /api/"); client.print(hueUsername);
    client.print("/lights/"); client.print(light);
    client.println("/state HTTP/1.1");
    client.println("keep-alive");
    client.print("Host: "); client.println(hueHubIP);
    client.print("Content-Length: "); client.println(command.length());
    client.println("Content-Type: text/plain;charset=UTF-8");
    client.println();
    client.println(command);
    client.stop();
  }
}

void setup() {
  WiFi.config(ip, gateway, subnet);
  WiFi.begin(ssid, pass);
  while (WiFi.status() != WL_CONNECTED) { delay(1); }
}

void loop() {
  getHue();
  if (onOffState == true) { setHue("{"on": false}"); }
  else                    { setHue("{"on": true}"); }
  ESP.deepSleep(0);                   // sleep until the next reset
}

Good to know

• The sketch uses the older Hue API, which was current at the time. Check the Hue documentation for what your bridge supports today.
• Never publish your Hue username. If it leaks, remove it from the bridge and make a new one.
• Philips and Hue are trademarks of their owners. This project is not made or approved by them.
• The repository holds the sketch and is under the MIT licence.

The project is in the ESP8266-Philips-hue-Switch repository on GitHub.