BLEBodyScale.md

MPBEKING CW306BLE

https://www.amazon.com/dp/B094FKXKQS

Android app is IKeeping

The scale broadcasts data constantly upon wake up with advertisement manufacturer data (may receive multiple with same content), device is not connectable

Seems like there is no battery state reported

All multi byte data is in small endian

 CE 01 02 00 00 00 00 00 00 01 CC FF
|MD|HR|HF| WEI |  IMPD  |DU|ST|CK|..|

MD: Device model (ca, cb, cc, ce, cf)
HR: Heartrate value
HF: If 0xC0 then HR byte is valid
WEI: Weight expressed always in kg multipled by 100 (e.g. BD 02 = 3026 = 30.26kg)
IMPD: Impedance for body fat calc, 0 if not supported
DU: Display unit, 0=kg 1=lb
ST: State, 0=stable 1=measuring
CK: Check byte (MD to ST XOR'ed)

esphome:
  on_boot:
    priority: -100
    then:
      lambda: |-
        id(body_scale_weight).publish_state(id(last_published_weight));
        id(body_scale_last_update).publish_state(id(last_published_time) > 0 ? id(last_published_time) : NAN);

esp32:
  board: esp32dev
  framework:
    type: esp-idf

api:
  encryption:
    key: ...

logger:

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

ota:
  - platform: esphome
    password: ...

time:
  - platform: sntp
    id: sntp_time
    servers:
      - 0.pool.ntp.org
      - 1.pool.ntp.org
      - 2.pool.ntp.org
  - platform: homeassistant
    id: ha_time

globals:
  - id: is_receiving
    type: bool
    restore_value: no
    initial_value: "false"
  - id: last_received_millis
    type: uint32_t
    restore_value: no
    initial_value: "0"
  - id: last_received_weight
    type: float
    restore_value: no
    initial_value: "0.0"
  - id: last_published_weight
    type: float
    restore_value: yes
    initial_value: "NAN"
  - id: last_published_time
    type: uint32_t
    restore_value: yes
    initial_value: "NAN"

bluetooth_proxy:

sensor:
  - id: body_scale_weight
    platform: template
    name: "Body Scale Weight"
    device_class: weight
    unit_of_measurement: kg
    lambda: "return id(last_published_weight);"
    update_interval: never

  - id: body_scale_last_update
    platform: template
    name: "Body Scale Last Update"
    device_class: timestamp
    lambda: "return id(last_published_time);"
    update_interval: never

esp32_ble_tracker:
  on_ble_manufacturer_data_advertise:
    - mac_address: "CE:E8:03:09:00:63"
      manufacturer_id: "0000"
      then:
        - lambda: |-
            // Validate length
            if(x.size() < 17)
              return;
            
            // Validate check byte
            uint8_t check = 0x00;
            for(uint8_t i = 6; i < 16; ++i)
              check ^= x[i];
            if(x[16] != check)
              return;

            // Validate stable
            if(x[15] != 0x00)
              return;

            // Record weight and timestamp
            id(last_received_weight) = ((uint16_t)(x[10] << 8 | x[9])) / 100.0;
            id(last_received_millis) = millis();
            id(is_receiving) = true;
            ESP_LOGD("ble_scale", "Received weight: %f kg at millis=%u", id(last_received_weight), id(last_received_millis));

interval:
  - interval: 1s
    then:
      - if:
          condition:
            lambda: "return id(is_receiving) && millis() - id(last_received_millis) > 5000;"
          then:
            - lambda: |-
                id(last_published_weight) = id(last_received_weight);
                id(last_published_time) = id(ha_time).utcnow().is_valid()
                                            ? id(ha_time).utcnow().timestamp
                                            : id(sntp_time).utcnow().is_valid()
                                            ? id(sntp_time).utcnow().timestamp 
                                            : 0;
                id(is_receiving) = false;
                id(body_scale_weight).publish_state(id(last_published_weight));
                id(body_scale_last_update).publish_state(id(last_published_time) > 0 ? id(last_published_time) : NAN);
                ESP_LOGI("ble_scale", "Published weight: %f kg at %u", id(last_published_weight), id(last_published_time));