There will be more posts to come, but for some time I have been playing around with home automation. One of the things I really wanted to do was utilise some form of machine learning to make decisions about when I wanted the Shed's Airconditioning or the wall fan turned on. I could have utilised rules in my OpenHAB based home automation system, however I'd already gotten reasonably creative with those and wanted a challenge.

I've been learning about machine learning for a while, in particular however it was this post on Stackoverflow and sentdex's Machine Learning with Python playlist that really helped me find a solution that appeared to fit what I was trying to do.

Using a couple of DHT22 sensor modules attached to Wemos D1 Mini, I was readily collecting Temperature data into OpenHAB.

Wemos D1 + DHT22 shown with USB Key for Scale

I settled on a Support Vector Machine algorithm as it seemed to best fit my dataset of "inTemperatur,inHumidity,outTemperature,outHumidity" and my decisions required being On or Off. The following video does an excellent job of explaining SVM.

I ended up writing a Python script that listens for change and learn events on the MQTT message bus which ties my home automation system together. OpenHAB fires change events when I'm present in the shed and fires learn events when I manually turn on AC or Fan on. If 'themachine' predicts a positive result greater than 95% certaintity it will fire back to a channel that OpenHAB has a switch sitting on to receive the event.

Example log of an event:

2017-01-11 20:53:52,721 INFO     I'm 97.92% sure you wanted the shedFan on. shed,26.70,58.10,21.00,81.30

You can find out more information about how to implement something similar on GitHub, it's MIT licensed so feel free to use the code how you'd like.

I have to admit, the first time it came on by itself was a little weird. I was standing on a stepladder doing some terminating in my rack (yes of course I have a full height network rack in my shed), thinking that it had gotten a little warm AC Turns on ... "woah". Skynet however is a long way off, well at least in my little home automation setup.

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