The Gory Details – Thermostat Tech Autopsy

I started worrying about what on Earth kind of things our Coroner Terrors would get from their Tech Autopsy of a thermostat?! It’s just a bunch of cheap plastic and electronics…so I did some digging and here’s what I’ve found…

I started off with the screen…I knew it was an LCD screen, but what exactly does that mean…how does an LCD screen even work?

LCD stands for Liquid Crystal Display and it’s actually a really cool state of matter that was discovered a billion years ago…well, back in 1888, at least.

You’ve probably learned about the states of matter…solid, liquid, gas and plasma…well liquid crystals are liquids but with some really cool solid-like behaviour.

When teamed up with polarizing filters (a filter that blocks light reflected off any non-metal surface) and a little electricity they can be used to change how much light they allow through…a feat that is used in the laptops, TVs…and Thermostats you use every day!

This is a bit advanced…but is the best basic description of Polarization in action. Plus I LOVE Khan Academy…you can learn anything about anything here and they’re fabulous!

The next thing I found was that most of these modern Thermostats are controlled by a tiny electronic component called, a thermistor. This little baby resists the amount of electricity that can flow through it depending on its temperature…so the thermostat is set up to equate temperature to the how much of an electrical jolt it’s receiving.

So the LCD is using electricity to control how much light can get through it…while the Thermostat is controlling how much electricity gets through by the changing temperature.

We should perform a delicate autopsy on our thermostat corpse, locate and remove the Thermistor. We can then rig it up to a multimeter (which can measure electrical current…and electrical resistance) and then play with heating or cooling the thermistor component to different temperatures and see if we can figure out which readings correspond to which temperatures!

Something like this:

So…we’ve got a way of talking about?




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