ESP8266 MQTT RGB LEDs Using JSON for Home Assistant

This project adds an easy way to create DIY lighting for Home Assistant, an amazing, extensible, open-source home automation system.

I was frustrated that the built-in MQTT light didn't support transitions (fading between colors/brightnesses), and that it uses multiple separate calls to set the different values (state (on/off), brightness, color), so I decided to make my own version. As of version 0.26, the MQTT JSON light platform has been merged into Home Assistant.

By sending a JSON payload (in an MQTT message), Home Assistant can include whichever fields are necessary, reducing the round trips from 3 to 1. For example, this is a sample payload including all of the fields:

{
  "state": "ON",
  "brightness": 120,
  "color": {
    "r": 255,
    "g": 100,
    "b": 100
  },
  "transition": 5
}

Installation/Configuration

To set this system up, you need to configure the MQTT JSON light component in Home Assistant and set up a light to control. This guide assumes that you already have Home Assistant set up and running. If not, see the installation guides here.

The Home Assistant Side

1. In your configuration.yaml, add the following:

   light:
     - platform: mqtt_json
       name: mqtt_json_light_1
       state_topic: "home/rgb1"
       command_topic: "home/rgb1/set"
       brightness: true
       rgb: true
       optimistic: false
       qos: 0

2. Set the name, state_topic, and command_topic to values that make sense for you.

3. Restart Home Assistant. Depending on how you installed it, the process differs. For a Raspberry Pi All-in-One install, use sudo systemctl restart home-assistant.service (or just restart the Pi).

The Light Side

I'm using ESP8266-01 microcontrollers for my lights because they are so cheap and small. The downside of the size and price is that programming them can be a bit of a hassle. There are many sites that go into detail, so I won't do it here. You'll need an ESP set up to work with the Arduino IDE. See the readme here for instructions.

1. Using the Library Manager in the Arduino IDE, install ArduinoJSON and PubSubClient. You can find the Library Manager in the "Sketch" menu under "Include Library" -> "Manage Libraries..."
2. Open the appropriate folder for your lights. For an RGB light, use mqtt_esp8266_rgb. For a light that only supports brightness, use mqtt_esp8266_brightness.
3. Update the config-sample.h file with your settings for pin numbers, WiFi settings, and MQTT settings.
4. Ensure that the CONFIG_MQTT_CLIENT_ID setting is a unique value for your network.
5. Set CONFIG_MQTT_TOPIC_STATE and CONFIG_MQTT_TOPIC_SET to match the values you put in your configuration.yaml.
6. Save the configuration file as config.h.
7. Open the .ino file in the Arduino IDE and upload to an ESP with the correct connections.

Wiring

For an RGB LED strip using N-MOSFETs for control, you'll want to wire it similar to this:

Note that the MOSFETs have pull-up resistors in this setup. This means that the lights may flash on when the module resets, but it was necessary to keep the ESP's pins in the right start state.