MQTT JSON Light


The mqtt_json light platform lets you control a MQTT-enabled light that can receive JSON messages.

This platform supports on/off, brightness, RGB colors, XY colors, color temperature, transitions, short/long flashing and white values. The messages sent to/from the lights look similar to this, omitting fields when they aren’t needed:

{
  "brightness": 255,
  "color_temp": 155,
  "color": {
    "r": 255,
    "g": 180,
    "b": 200,
    "x": 0.406,
    "y": 0.301,
    "h": 344.0,
    "s": 29.412
  },
  "effect": "colorloop",
  "state": "ON",
  "transition": 2,
  "white_value": 150
}

In an ideal scenario, the MQTT device will have a state topic to publish state changes. If these messages are published with the RETAIN flag, the MQTT light will receive an instant state update after subscription and will start with the correct state. Otherwise, the initial state of the light will be off.

When a state topic is not available, the light will work in optimistic mode. In this mode, the light will immediately change state after every command. Otherwise, the light will wait for state confirmation from the device (message from state_topic).

Optimistic mode can be forced, even if state topic is available. Try enabling it if the light is operating incorrectly.

# Example configuration.yaml entry
light:
  - platform: mqtt_json
    command_topic: "home/rgb1/set"

Configuration Variables

name

(string)(Optional)The name of the light.

Default value: MQTT JSON Light

unique_id

(string)(Optional)An ID that uniquely identifies this light. If two lights have the same unique ID, Home Assistant will raise an exception.

command_topic

(string)(Required)The MQTT topic to publish commands to change the light’s state.

brightness

(boolean)(Optional)Flag that defines if the light supports brightness.

Default value: false

brightness_scale

(integer)(Optional)Defines the maximum brightness value (i.e. 100%) of the MQTT device.

Default value: 255

color_temp

(boolean)(Optional)Flag that defines if the light supports color temperature.

Default value: false

effect

(boolean)(Optional)Flag that defines if the light supports effects.

Default value: false

effect_list

(string list)(Optional)The list of effects the light supports.

flash_time_long

(integer)(Optional)The duration, in seconds, of a “long” flash.

Default value: 10

flash_time_short

(integer)(Optional)The duration, in seconds, of a “short” flash.

Default value: 2

optimistic

(boolean)(Optional)Flag that defines if the light works in optimistic mode.

Default value: true if no state topic defined, else false.

qos

(integer)(Optional)The maximum QoS level of the state topic.

Default value: 0

retain

(boolean)(Optional)If the published message should have the retain flag on or not.

Default value: false

rgb

(boolean)(Optional)Flag that defines if the light supports RGB colors.

Default value: false

state_topic

(string)(Optional)The MQTT topic subscribed to receive state updates.

white_value

(boolean)(Optional)Flag that defines if the light supports white values.

Default value: false

xy

(boolean)(Optional)Flag that defines if the light supports XY colors.

Default value: false

hs

(boolean)(Optional)Flag that defines if the light supports HS colors.

Default value: false

availability_topic

(string)(Optional)The MQTT topic subscribed to receive availability (online/offline) updates.

payload_available

(string)(Optional)The payload that represents the available state.

Default value: online

payload_not_available

(string)(Optional)The payload that represents the unavailable state.

Default value: offline

Make sure that your topics match exact. some-topic/ and some-topic are different topics.

RGB, XY and HSV can not be used at the same time in state_topic messages. Make sure that only one of the color models is in the “color” section of the state MQTT payload.

Comparison of light MQTT platforms

Function mqtt mqtt_json mqtt_template
Brightness
Color temperature
Effects
Flashing
RGB Color
Transitions
XY Color
HS Color
White Value

Examples

In this section you find some real-life examples of how to use this sensor.

Brightness and RGB support

To enable a light with brightness and RGB support in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
light:
  - platform: mqtt_json
    name: mqtt_json_light_1
    state_topic: "home/rgb1"
    command_topic: "home/rgb1/set"
    brightness: true
    rgb: true

Brightness and no RGB support

To enable a light with brightness (but no color support) in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
light:
  - platform: mqtt_json
    name: mqtt_json_light_1
    state_topic: "home/rgb1"
    command_topic: "home/rgb1/set"
    brightness: true

Brightness Scaled

To enable a light using a brightness scale other than 8bit the brightness_scale option may be added to denote the “fully on” value:

# Example configuration.yaml entry
light:
  - platform: mqtt_json
    name: mqtt_json_light_1
    state_topic: "home/light"
    command_topic: "home/light/set"
    brightness: true
    brightness_scale: 4095

Home Assistant will then convert its 8bit value in the message to and from the device:

{
  "brightness": 4095,
  "state": "ON"
}

HS Color

To use a light with hue+saturation as the color model, set hs to true in the platform configuration:

light:
  - platform: mqtt_json
    name: mqtt_json_hs_light
    state_topic: "home/light"
    command_topic: "home/light/set"
    hs: True

Home Assistant expects the hue values to be in the range 0 to 360 and the saturation values to be scaled from 0 to 100. For example, the following is a blue color shade:

{
  "state": "ON",
  "color": {
    "h": 24.0,
    "s": 100.0
  }
}

Brightness and RGBW support

To enable a light with brightness, RGB support and a separate white channel (RGBW) in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
light:
  - platform: mqtt_json
    name: mqtt_json_light_1
    state_topic: "home/rgbw1"
    command_topic: "home/rgbw1/set"
    brightness: true
    rgb: true
    white_value: true

Implementations

  • A full example of custom lighting using this platform and an ESP8266 microcontroller can be found here. It supports on/off, brightness, transitions, RGB colors, and flashing.

  • There is also another implementation forked from the above repo, it supports all the same features but is made for addressable LED strips using FastLED on a NodeMCU V3 it can be found here.

  • McLighting is another ESP8266 firmware for WS2812 addressable LEDs.

  • MQTT JSON Light is another implementation for ESP8266 including MQTT discovery.

  • esphomelib is a library for ESP8266 and ESP32 boards that has many of Home Assistant’s MQTT features (like discovery) pre-implemented and provides high-level abstractions for components such as lights or sensors.

  • AiLight is a custom firmware for the Ai-Thinker (and equivalent) RGBW WiFi light bulbs that has an ESP8266 onboard and controlled by the MY9291 LED driver. It implements the MQTT JSON light platform and supports ON/OFF, RGBW colours, brightness, colour temperature, flashing and transitions. Also it includes MQTT Auto Discovery) and the MQTT Last Will and Testament is enabled as well.