We’ve all been there. Your current project has hit a wall, or the next step will take days to complete, and you need something to do in the meantime. So you start a project that you envision will fit nicely in the gap, and then, inevitably, it doesn’t. Maybe it even takes so long that the original project gets finished first. So what? There’s nothing wrong with that, especially when the filler project turns out as well as this drink temperature monitor disguised as a circuit sculpture (video, embedded below). Just put your mug on the coaster, and the weight of it activates a hidden switch, which causes the sculpture to display its secret LEDs.

[MakeFunStuff] wanted to make something that looked less like a circuit and more like art, while building a tool that could determine the relative hotness of a beverage. Such a a useful circuit sculpture sounds like a tall order to us, but [MakeFunStuff] pulled it off with finesse and style.

The circuit is based around this Sputnik-looking standalone IR temperature sensor which, as [MakeFunStuff] aptly describes, is “a single-pixel infrared camera that picks up everything in a 90° cone starting at the sensor.”

[MakeFunStuff] paired this easy-to-use sensor with an Arduino Nano and five LEDs that show how hot a beverage is on a scale from 1 to 5. The sensor is hidden in plain sight, suspended from the top of the brass rod sculpture and blending in perfectly. We love that the LEDs are hidden behind a thin layer of carefully-drilled wood and agree that a drill press would have been much easier.

The code is set up for just about every temperature scale from Celsius to Rømer, so that solves that argument. [MakeFunStuff] went with the Kelvin scale because science. Our favorite thing about this video is that [MakeFunStuff] shared their failures and fixes as they built their way toward answering the questions of how to suspend the sensor over the drink, and how best to display the heat level while hiding the electronics. Go grab a hot cup of something and check it out after the break while you let it cool off the normie way.

We admit that we would likely zone out while waiting for the LEDs to disappear. Here’s a smart coaster that uses an ESP8266 to send a message to Discord when your beverage has reached the perfect drinking temperature.

Thanks for the hot tip, [Perry]!