Reads 1-wire sensor bus (DS18B20), M-bus (and parse the messages), and inputs (with debouncing).Accepts setpoints for thermostats and output states over MQTT.Sends all sensor values and states over MQTT.Expansion port with M-bus slave (for meter reading)įor the cabin application I've written a Python program which:.1-wire bus transceiver (DS2482) to maximize range for a DS18B20 temperature sensor bus.4 x 1 A 230 VAC solid state relays with external snubber circuits, primarily intended to control contactors (and other small but inductive loads).2 x 16 A 230 VAC Omron relays that can handle inductive loads with large inrush current.

The server runs an MQTT broker and an additional instance of Home Assistant in a docker container.

The Raspberry Pi connects to my server using MQTT through 4G.

All logs with significant activity are written to RAM, to minimize flash wear.

The Raspberry Pi runs a very minimal software setup, and only does what really needs to run locally and can't handle an internet outage (like the thermostat logic).

All sensors are wired to maximize stability and avoid the need to replace batteries (important because the cabin is a remote location).What I ended up with is a small unit based on a Raspberry Pi Zero that can be mounted on a DIN rail. Unlike my home, which has about 50 separate CAN bus nodes scattered around the house, I wanted a compact and simple solution to control and monitor our cabin. Summary A small PLC-like unit for home automation based on a Raspberry Pi Zero that can be mounted on a DIN rail in a fuse box. Raspberry Pi Zero PLC for home automation

Home assistant raspberry pi zero w