This is a simple script I call from cron to control a Z-wave switch that in turn controls the electric engine heater of my car.
Based on the time I configure that I want to leave home, it will turn on the heater at an appropriate time depending on outside temperature.
This way a bit of energy is saved, as it's only when it's really cold that the heater should run for any extended period of time. See https://www.calix.se/en/support/faq
It's used together with my Home Assistant installation. The cron job calls the Home Assistant API to turn on and off switches, and to check outside temperature.
This is a quite stupid little script that I wrote since I have not yet found the time to learn enough about Home Assistant to do it all inside the UI and backend.
Install by running python setup.py install in a virtualenv on some
machine. I run it from cron using the following:
* 0-7 * * mon /opt/engineheater/bin/start_engineheater --verbose --homeassistant-url https://localhost --toggle-switch input_boolean.auto_peugeot sensor.humidity_5_1 switch.peugeot_switch 06:15
The above command line is instructing the script to:
- Talk to Home Assistant at http://localhost
- Check the outside temperature by asking for the value of sensor.humidity_5_1 (it will ask for a V_TEMP attribute)
- If the outside temperature is such that it's time to turn on the heater, do so by turning on switch.peugeot_switch via HA.
- Time the heater such that it has been running for an appropriate time when I leave at 06:15 using the french-made car with a brand that is very hard to spell.
- Do this check once a minute from midnight until 07:00.
- Only do the above if the input_boolean.auto_peugeot is on.
Be aware that everything happens in the timezone of the server, not in the timezone set in Home Assistant.
See start_engineheater --help for further details.
Now when I'm done with all this, I really should put it all in the HA UI instead.