If I understand you correctly, you have:
- Bluetooth and zwave sensors in the greenhouse (no AC power available).
- The transmitted sensor data is received by Home Assistant (on an RPi) in a nearby shed (AC power available).
- Another Home Assistant system is in the house and the goal is to have it receive the sensor data collected by the system in the shed.
Virtually all solutions involve using MQTT as a means of sharing data between the two instances of Home Assistant. In light of that, my original idea was to replace the shed’s instance of HA with something simpler, something designed to receive Bluetooth-based data and relay it via MQTT. It involves far less configuration (and maintenance) that running a full-blown HA system in the shed.
HOWEVER, that idea is now rendered worthless by the fact you are also using zwave-based sensors in the greenhouse. The simple ‘gateway’ device I had in mind cannot handle zwave. So we’re back to the status quo of two HA systems needing to share data.
The commonly-used solution for connecting Home Assistant systems is MQTT Statestream. It would be used to make your shed-based HA system send all its sensor data via MQTT.
That’s one-half of the equation. The other half is to make the house-based HA system receive the MQTT data. In brief, you must create one MQTT sensor (on the house-based system) for each sensor you wish to monitor (on the shed-based system).
If you only have 2-3 sensors then it’s not much of hardship to manually define them on the house-based system. If you have ten or more then it can become a tedious task. The author of this post devised a fairly clever way of automatically adding the sensors using MQTT Discovery: