Useful Sensor: Cardinal Wind Direction for Home Assistant

At a glance – gustier than usual this morning.

As someone who cycles to work most days, I keep a pretty close eye on the weather. One thing I like to know is which way the wind is blowing – a strong headwind means I should maybe opt for the road bike, not the cruiser. Home Assistant has a ton of weather platforms – and the Dark Sky one that I prefer tracks wind direction. The only problem is it returns the direction in degrees, which is meaningless to me.

See below for a template sensor that will convert degrees to a human-readable cardinal direction.

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Useful Sensor: Bayesian Sleep Detection in Home Assistant

Sleep is not something I can directly observe in my smart home (at least not until I build that DIY bed sensor). It would be nice to know though – then the alarm could be set, doors locked, thermostat set, music volume slowly dimmed, and internet bandwidth reprioritized automatically when it’s time for bed. We spend a lot of time sleeping in our homes, so it makes sense to be able to detect it.

Using Home Assistant’s Bayesian binary sensor it’s possible to guess pretty accurately when everyone’s tucked away. See below for example YAML and explanation.

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Home Assistant: Making My Plants Talk with IoT Sensors and a Python Script

Living in an urban city without a garden, I have been exercising my green thumb by accumulating more and more houseplants. I have them tucked away in every light-filled corner, hanging from every rafter in my tall ceilings. Which is a problem, because I have to get a ladder out to water most of them!

Using some cheap plant soil sensors and a simple Python script, I will have Home Assistant check all of my plants and make a list of which need my attention. Then when more than a few need to be watered, I can be notified or have the voice assistant give me an update.

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Useful Sensor: Motion Last Seen & Meta Motion Sensor

You know what’s great about motion sensors? They are very, very cheap to build yourself. All it takes is an esp8266 module like the Wemos D1 Mini, some PIR sensors, and the ESP Easy firmware and you can have a bunch up and running in a few minutes. I haven’t DIYed a battery powered one yet, but there are plenty of great Z-Wave ones available.

Once you have a couple of motion sensors in your smart home, you can have Home Assistant track the last place it saw motion. This is a useful bit of info – useful as a condition for your automations, or as an input for a bayesian binary sensor. See below for YAML to create a meta-motion sensor with a history.

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Presence Detection Part 1: Home Assistant & Bayesian Probability

One of the most useful things to track for home automation is whether anyone is home or not. If you want the lights to turn off when no one is home, the vacuum robot to run when you’re at work, or the heat to come on before you arrive home on a cold night you need to reliably be able to tell if the house is occupied.

How can we track the state of something that is not directly observable? We can’t plug ourselves directly into the internet (…yet). After trying several approaches to monitoring presence, I’ve come up with a method that is very near 100% reliable.

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