Add support Mi Body Composition Scale S400

[razor-4eg]

Cant figure out how to create a converter for Xiaomi Scale s400 BLE

here the device info:

extra:
  cloud_fw: 2.1.1_0057
  cloud_name: Body Composition Scale
  did: blt.3.1i0oijp3sk400
  mac: 84:46:93:20:07:0a
  market_brand: Xiaomi
  market_model: 12505, yunmai.scales.ms103
  market_name: Body Scale s400
  rssi_54ef4437c787: -62
  seq: 24
  type: ble
last_seen:
  54ef4437c787: 1m6s
listeners: 5
model: 12505
params: {}
ttl: 1h5m
uid: 84469320070a

Here is debug logs with it (blt.3.1i0oijp3sk400)
debug.log

[tufeikafei]

I have the s400 pro，but I don't know how to debug = =

[PoiScript]

the s400 scale measures three metrics: impedance, heart rate and weight and combines these values into a single value value when reporting to gateway.

The formula is

(impedance * 10) << 18 + (heart_rate - 50) << 11 + (weight * 10)

To decode it properly, you need to add a custom converter:

from dataclasses import dataclass
from custom_components.xiaomi_gateway3.core.devices import *
from homeassistant.components.sensor import (
    SensorDeviceClass,
    SensorStateClass,
)


@dataclass
class S400RawDataConv(BaseConv):
    def decode(self, device: "XDevice", payload: dict, value: int):
        if value > 1:
            weight = value & (2**11 - 1)
            heart_rate = (value >> 11) & (2**7 - 1)
            impedance = value >> 18
            payload["raw_data"] = value
            if weight != 0:
                payload["weight"] = weight / 10
            if heart_rate > 0 and heart_rate < 127:
                payload["heart_rate"] = heart_rate + 50
            if impedance != 0:
                if weight != 0:
                    payload["impedance_high"] = impedance / 10
                else:
                    payload["impedance_low"] = impedance / 10


DEVICES = [
    {
        18639: [
            "Xiaomi",
            "Body Composition Scale S400",
            "12505",
            "yunmai.scales.ms103",
        ],
        "spec": [
            BaseConv(
                "weight",
                "sensor",
                entity={
                    "name": "Weight",
                    "icon": "mdi:human",
                    "class": SensorDeviceClass.WEIGHT,
                    "statistics": SensorStateClass.MEASUREMENT,
                    "units": "kg",
                },
            ),
            BaseConv(
                "heart_rate",
                "sensor",
                entity={
                    "name": "Heart Rate",
                    "icon": "mdi:heart-pulse",
                    "statistics": SensorStateClass.MEASUREMENT,
                    "units": "bpm",
                },
            ),
            BaseConv(
                "impedance_low",
                "sensor",
                entity={
                    "name": "Impedance (low)",
                    "icon": "mdi:omega",
                    "statistics": SensorStateClass.MEASUREMENT,
                    "units": "ohm",
                },
            ),
            BaseConv(
                "impedance_high",
                "sensor",
                entity={
                    "name": "Impedance (high)",
                    "icon": "mdi:omega",
                    "statistics": SensorStateClass.MEASUREMENT,
                    "units": "ohm",
                },
            ),
            # https://home.miot-spec.com/spec/yunmai.scales.ms107
            S400RawDataConv("raw_data", "sensor", mi="11.e.1022.p.2"),
        ],
    }
] + DEVICES

For other metrics like BMI, body fat, bones mass, you can leverage the bodymiscale custom component.

Final result:

---

This setup is only works for single user. I only tested with yunmai.scales.ms107 but it should also works with yunmai.scales.ms103 and yunmai.scales.ms104.

[AlexxIT]

@PoiScript can you provide messages examples? So I can write tests on your converters.

[PoiScript]

@AlexxIT sure! here're example data:

# case 1
input 260823     => weight = 72.7
# case 2
input 1338768096 => weight: 73.6, impedance_high: 510.6
input 1234960384 => impedance_low: 471.1
# case 3
input 1343068894 => weight 73.4, heart_rate: 101, impedance_high: 512.3
input 1240727552 => impedance_low: 473.3

Note that heart rate and impedance data can be missing (case 1) when wearing shoes, as the scale cannot measure them.

Heart rate measurement can be turned off in settings. (case 2)

The scale will report two impedance values (both case 2 and case 3) which is likely measured at different frequencies

[AlexxIT]

https://github.com/AlexxIT/XiaomiGateway3/releases/tag/v4.0.7

[razor-4eg]

Great, but you using a wrong id for it.

id for s400 is 12505, so I changed your code from:

18639: [
            "Xiaomi",
            "Body Composition Scale S400",
            "12505",
            "yunmai.scales.ms103",
        ],

to:

12505: ["Xiaomi", "Body Composition Scale s400", "12505", "yunmai.scales.ms103"]

and it start working.

Thank you!)

[tufeikafei]

Hi I have a s400 pro. ID: 19205
The model :xiaomi.scales.ms110
I don't know how to debug it= =.
And the detail code is blow:
https://home.miot-spec.com/spec/xiaomi.scales.ms110