xiaomi-scale-2-mqtt

Reads Mi Body Composition Scale 2 from a Bluetooth device and sends it to MQTT.

Credits

• https://dev.to/henrylim96/reading-xiaomi-mi-scale-data-with-web-bluetooth-scanning-api-1mb9 - reverse-engineering Mi Scale 2 protocol
• https://github.com/oliexdev/openScale/wiki/Xiaomi-Bluetooth-Mi-Scale - reverse-engineering Mi Scale 1 protocol
• https://github.com/perillamint/node-xiaomi-scale - library for Mi Scale 1 used as a base for this integration

How does it work?

• It queries for all Mi Scale 2 devices via Bluetooth
• When a scale broadcasts its data, the script would catch and parse it
• If the data is stable, then it's sent to MQTT broker
• Then you can use it in other tools (I needed it in Home Assistant, that's why I wrote this)

How to run it?

1. Build the container:

docker build -t xiaomi-scale-2-mqtt .

2. Run the container (for configuration, see below):

docker run -it --net=host \
    -d --name=xiaomi-scale-2-mqtt \
    -e DATE_OF_BIRTH=<put your DoB here> \
    -e SEX=<your sex here> \
    -e HEIGHT=<your height here> \
    -e TZ=<your timezone here> \
    xiaomi-scale-2-mqtt

3. Install MQTT client to test it: npm install -g mqtt
4. Run it to listed for the MQTT messages: mqtt sub -t 'mi.scale2' -v
5. Step on your scale, wait for it to stabilize, then MQTT client should receive a bunch of JSON.

Integrating it into Home Assistant

1. Set up the MQTT integration for Home Assistant
2. Add this to sensors.yaml:

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Weight'
  value_template: "{{ value_json.weight }}"
  unit_of_measurement: "kg"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Last update'
  value_template: "{{ as_timestamp(value_json.date) | timestamp_custom('%d %b %Y %H:%M') }}"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - BMI'
  value_template: "{{ value_json.bmi|round(2) }}"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Ideal weight'
  value_template: "{{ value_json.idealWeight|round(2) }}"
  unit_of_measurement: "kg"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Metabolic age'
  value_template: "{{ value_json.metabolicAge|round(2) }}"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Protein percentage'
  value_template: "{{ value_json.proteinPercentage|round(2) }}"
  unit_of_measurement: "%"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - LBM'
  value_template: "{{ value_json.lbm|round(2) }}"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - BMR'
  value_template: "{{ value_json.bmr|round(2) }}"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Fat percentage'
  value_template: "{{ value_json.fatPercentage|round(2) }}"
  unit_of_measurement: "%"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Muscle mass'
  value_template: "{{ value_json.muscleMass|round(2) }}"
  unit_of_measurement: "kg"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Bone mass'
  value_template: "{{ value_json.boneMass|round(2) }}"
  unit_of_measurement: "kg"

- platform: mqtt
  state_topic: 'mi.scale2'
  name: 'Mi Scale 2 - Visceral fat'
  value_template: "{{ value_json.visceralFat|round(2) }}"

3. Restart Home Assistant
4. Create a Lovelace UI card which uses these newly created sensors:

type: entities
entities:
  - entity: sensor.mi_scale_2_weight
  - entity: sensor.mi_scale_2_ideal_weight
  - entity: sensor.mi_scale_2_last_update
  - entity: sensor.mi_scale_2_bmi
  - entity: sensor.mi_scale_2_metabolic_age
  - entity: sensor.mi_scale_2_protein_percentage
  - entity: sensor.mi_scale_2_fat_percentage
  - entity: sensor.mi_scale_2_bmr
  - entity: sensor.mi_scale_2_muscle_mass
  - entity: sensor.mi_scale_2_bone_mass
  - entity: sensor.mi_scale_2_visceral_fat
state_color: false
title: Scale

5. See this as a Home Assistant card.

Configration

All the configuration is done through the environmental variables.

• LOG_LEVEL - integration logging level. Default: info. If something isn't working, try setting it to debug or even trace and check what's inside.
• MQTT_URL - MQTT broker url. Default: mqtt://localhost.
• MQTT_TOPIC - MQTT topic. Default: mi.scale2.
• DEBOUNCE - within that interval, only 1 measurement per scale would be sent. Default: 30.
• DATE_OF_BIRTH - date of birth of a person who's using the scale, in this format: YYYY-MM-DD. Used for calculating the person's age.
• SEX - sex of a person who's using the scale, either male or female.
• HEIGHT - height of a person who's using the scale.

If any of the last 3 parameters is not set, the script won't be able to calculate a bunch of parameters (like BMI, ldeal weight etc.).