Contents: [Dobrica Pavlinušić's random unstructured stuff]
• Dobrica Pavlinušić's random unstructured stuff (info) 
• Dobrica Pavlinušić's random unstructured stuff (decode using gatttool) 
• Dobrica Pavlinušić's random unstructured stuff (open source firmware) 
• Dobrica Pavlinušić's random unstructured stuff (simple shell to send reading to influx) 
• Dobrica Pavlinušić's random unstructured stuff (Home Assistant) 

info
https://hackaday.com/2020/12/08/exploring‑custom‑firmware‑on‑xiaomi‑thermometers/ 
https://github.com/atc1441/ATC_MiThermometer 
https://github.com/pvvx/ATC_MiThermometer 
Xiaomi Smart LCD Screen Digital Thermometer 2 Mijia Bluetooth Temperature Humidity Sensor Moisture Meter Mijia App
https://www.aliexpress.com/item/1005002401046796.html 
LYWSD03MMC
decode using gatttool
https://ndimension.design.blog/2021/12/16/reading‑data‑from‑xiaomi‑mi‑temperature‑and‑humidity‑monitor‑2‑lywsd03mmc/ 
root@rpi2:/home/pi# sudo hcitool lescan
LE Scan ...
A4:C1:38:D8:3F:9C ATC_D83F9C

open source firmware
https://github.com/bentolor/xiaomi‑mijia‑bluetooth‑firmware 
simple shell to send reading to influx
https://github.com/dpavlin/air‑quality/blob/master/ble‑mijia.sh 
https://github.com/dpavlin/air‑quality/blob/master/system/ble‑mijia%40.service 
https://www.youtube.com/watch?v=NXKzFG61lNs 
Home Assistant 
connected to home assistant using https://esphome.github.io/bluetooth‑proxies/ 
get bindkey using https://atc1441.github.io/TelinkFlasher.html 
https://esphome.io/components/sensor/xiaomi_ble.html?highlight=xiaomi_ble#obtaining‑the‑bindkey 
[core-ssh ~]$ tail -18 config/.storage/core.config_entries
      {
        "entry_id": "574243c45c4485523ec174e18cfcf1ad",
        "version": 1,
        "domain": "xiaomi_ble",
        "title": "Temperature/Humidity Sensor DC63 (LYWSD03MMC)",
        "data": {
          "bindkey": "a6da0c1d99200efe9c9afb8fd9a534ef"
        },
        "options": {},
        "pref_disable_new_entities": false,
        "pref_disable_polling": false,
        "source": "bluetooth",
        "unique_id": "A4:C1:38:90:DC:63",
        "disabled_by": null
      }
    ]
  }

flash new firmware to sensor https://github.com/pvvx/ATC_MiThermometer 
open in chrome on android to flash firmware,
 change announcement to BTHome,
 set time,
 disconnect to start sending data to home assistant