eblanton / hasensor

Home Assistant/Automation Sensors

This package provides a HA sensor service for Raspberry Pi computers communicating via MQTT. It is designed to integrate easily with Home Assistant, although it could be used with any service.

Using the Demonstration Script

The main.py here is currently more of a demonstration than a complete project, but ... that said, I'm using it. It has a number of arguments that should be straightforward if you're familiar with MQTT and Home Assistant (although not all are complete, like discoverability, which requires more implementation in the individual sensors), but the sensor configuration is unique to this package.

The -s (or --sensor) argument accepts a sensor description, which is a string that includes the type of the sensor plus whatever arguments and configuration it may require/accept. It is a set of options separated by colons, like:

bme280:name=climate:start=NOW:period=300:address=0x76

This declares that you want a BME280 sensor, that it is a periodic sensor that should start as soon as possible and fire once every 300 seconds, that its MQTT subtopic (which is appended to the prefix supplied with -p) is climate, and that it should be found at the I2C address 0x76 instead of the default 0x77.

Every sensor supports a few arguments:

• name: This is the MQTT subtopic for this sensor. This will be appended to the package topic provided with -p on the command line to create the topic on which the sensor readings will be reported. For example, if you run with -p bedroom/master and name=climate, you'll get readings on the topic bedroom/master/climate.
• start: This is the time (in floating point seconds since the Epoch) at which the first sensor reading should be taken and reported. The special value NOW means to start as soon as the sensor is created.
• period: This is a relative number of floating point seconds between sensor readings. If period is not supplied, or is supplied as 0, the sensor will fire only once.

Other arguments, such as the address of the BME280, are sensor-specific. Every sensor-derived class should have an _argtypes class variable declaring the arguments it accepts and their types, if no other documentation is forthcoming.