Apparently maintaining an onpen BLE conection uses a lot of precious miliamps.

The modules ran out of battery after 1 month of constant streaming.
Only one sensor is still working, they stopped broadcasting one by one in the spam of one week.


I have in mind two solutions for this:

1. Instead of a permanent BLE connection and constant streaming of data,
   the raspberry could each 2-5 minutes create a BLE conection and read the temp+humidity data once, then close the connection.
2. Modify the firmware/use a modified version of the xiaomi sensors, so they include temperature and humidity data in their advertisment data.

https://microchipdeveloper.com/wireless:ble-link-layer-packet-types