A nice talk by Erwin de Keijzer. Full title: do you need to take general relativity into consideration when measuring your elevator?.
Erwin has an elevator inside his, otherwise quite normal, house. An old lady used to live there and she needed an elevator to get around the house. The elevator is real slow, but handy for moving heavy stuff around.
He wanted to do some automation around it… Some rules/goals:
Know where the elevator is
Add music when the elevator is moving
Play announcements when the elevator stops at a floor
Don’t break the elevator
Don’t mess with the internal electronics.
His first attemt was to use a cheap ultrasonic sensor. The lift shaft was too high, though. And it sometimes picked up the support beams instead of the lift. He now uses the sensor for his standing desk.
Attempt 2: “TF Luna LiDAR”. A raspberry pi is connected to it and uses NATS and some Go code to write the measurements to prometheus.
With the position handled, he moved to alerting. Stuck between floors (you have to keep pushing the button to move), moving too fast, moving too slowly, elevator out of bounds.
When investigating the data, he noticed that the location of the lift when at rest, shifts a little bit throughout the day. He added temperature measurement: perhaps it had to do with the temperature? Not really. So he started brainstorming. Perhaps the way the earth moves? General relativity? It could be anything.
So he imported all the data into a jupyter notebook and started scatterplotting and histogramming… In the end it was a small inaccuracy in the elevator itself when stopping at a floor. Though, if you squint at the graphs in the right way… a little temperature dependency seems to be present, but just a little.
He used kubernetes. The raspberry pi runs k3s and is tainted to just run the pi stuff. Another server in his home runs the rest.
He showed a video of his elevator in action :-) Music when the elevator is moving. Note: the volume is decreased the higher you are in the elevator shaft as the speaker is at the top of the shaft…
My name is Reinout van Rees and I work a lot with Python (programming language) and Django (website framework). I live in The Netherlands and I'm happily married to Annie van Rees-Kooiman.
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