Like many people at the moment, I’ve used the enforced lockdown to have a bit of a tidy-up at home, in doing so I found a stack of Raspberry PIs which I’d neglected, so I decided to resurrect one.

Now, as a (relevant) aside, I like tech, so it won’t be that suprising to find out that some while back I installed motion detectors to control the lights in some of our communal areas (kitchen, bathroom etc) to stop the kids leaving them all all night.

These are just basic off the shelf solutions in the Philips Hue range and to borrow a phrase from another company, they ‘just work’.

So, having found the PI (the solution!), I needed to find a problem to fix, not the ideal approach for sure, but hey I was bored.

Putting 1+1 together, turns out the API set for the Hue system is relatively simple, so in just a few lines of Python, you can get access to all the Hue kit. It also turns out that a motion sensor isn’t just a motion sensor! In there, there’s a separate temperature sensor and a light level sensor, and with a simple cron job, you can set this up to log every 15 min or so in just a few lines of code.

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import urllib3
from datetime import datetime

url = 'ip to your hue gateway + key /sensors'
r = requests.get(url,  verify=False)

hue = json.loads(r.content)

labels = {
    '9': 'Bathroom',
    '21': 'Loo',
    '27': 'Kitchen',
}

for i in hue:
    name = hue[i]['name']
    temperature, light_level = None, None
    if 'temperature' in name:
        temperature = hue[i]['state']['temperature']/100
        with open('/home/pi/dev/hue/temps.csv', 'a') as file:
            file.write(f"{datetime.now()}, {labels[i]}, {temperature}\n")

It’s not just Hue! Our heating / security systems also have sensors all over the place - and while it took a bit more effort, it turns out every door/window sensor also have a temperature sensor, every plug / relay also has a temperature sensor and so on.

So I’ve started logging a wealth of ‘free’ data about my home, data I home to be able to mine and extract value down the line, even it if is only of use / value to me, even if it is just to save money on heating.

Turns out then I didn’t just find an unused Raspberry PI in the back of that cupboard, but a wealth of untapped data too!