The beauty of websites that host write-ups of hardware hacker projects is that you will find fantastic electronic devices that you never knew you wanted. For example, how many people do you know that are just dying to get their hands on a very low-resolution infrared camera to hang on their wall? I can count all of them on zero hands.
But taking a look at the Infrared Mirror that Reuben recently built, you may find that you will want to build your own. It is not really useful for any practical purpose, but the craftsmanship is fantastic and it would be an interesting, interactive piece of artwork to liven up your home.
The infrared mirror was built with an Adafruit MLX90640 infrared camera, a Teensy 3.2 microcontroller development board, and a dozen 8x8 LED panels in a 24x32 pixel configuration. The arrangement of the LED panels perfectly matches the 24x32 resolution of the camera. The Teensy 3.2 was chosen because it has the raw horsepower necessary to drive the 768 individually addressable RGB LEDs with a high refresh rate. The frame was built with aluminum extrusions, acrylic, and baltic birch plywood. The minimal controls consist of an on/off switch, and a dial to adjust the brightness of the display.
Placing anything, such as a hand, in front of the infrared camera will reveal (in a blocky, low-resolution way) the heat signature of the object on the display panel. Rather than shine the bare LEDs, which can be quite harsh, right at viewers, the LEDs are cleverly diffused with plastic window privacy coverings for a very pleasing look.
The front of the frame also has a small cutout for a motion detector, so that when everyone tires of playing a literal game of Hot or Not, a screensaver can kick in to keep the display visually interesting. Reuben ends his write-up with the hope that his Infrared Mirror project might inspire others to build something awesome. I think that mission will be accomplished, Reuben.