Xiaomi LYWSD03MMC

unverified library/ble/xiaomi-lywsd03mmc.hal.yaml

Id	xiaomi-lywsd03mmc
Manufacturer	Xiaomi
Model	LYWSD03MMC
Driver	ble
Hazard	low
Limits	unconfirmed This file has read channels only, so nothing in the file changes the device.

Read channels

Channel	Type	Unit	Every
temperature	number	degC	stream
humidity	number	%	stream
battery_voltage	number	V	stream

openhal: "0.1"
device: { name: Xiaomi Mi Temperature and Humidity Monitor 2, model: LYWSD03MMC, manufacturer: Xiaomi }
id: xiaomi-lywsd03mmc
match:
  ble_name: "^LYWSD03MMC$"
connect: { ble: auto, scan_timeout: 10 s, timeout: 15 s }
read:
  temperature:
    unit: degC
    stream: true
    range: [0, 60]
    map: { characteristic: ebe0ccc1-7a0a-4b0c-8a1a-6ff2997da3a6, format: sint16, byte: 0, scale: 0.01 }
  humidity:
    unit: percent
    stream: true
    range: [0, 100]
    map: { characteristic: ebe0ccc1-7a0a-4b0c-8a1a-6ff2997da3a6, format: uint8, byte: 2 }
  battery_voltage:
    unit: V
    stream: true
    range: [2, 3.3]
    map: { characteristic: ebe0ccc1-7a0a-4b0c-8a1a-6ff2997da3a6, format: uint16, byte: 3, scale: 0.001 }
hazard: low
notes: >-
  Suggested limits. A person must confirm every limit before this device can be written.
  This is the sensor on Xiaomi's own firmware. It sends temperature, humidity and battery voltage together in
  one notification while connected, and the coin cell drains faster while the hub stays connected. This file
  only reads.
provenance: { source: library, by: OpenHAL starter library, at: 2026-10-25, verification: { status: unverified } }