Not every build needs to be immediately useful or revolutionary. Plenty of builds are just for fun, for education, or even purposefully useless but still challenging. This clock, for example, might fit into all three categories. It’s a clock that displays time through a QR code, making it completely inscrutable unless you have a device which likely has its own readable clock on it already.
The QR Code clock comes to us from [Aaron] and is based on the now-ubiquitous ESP32 WiFi chip. The ESP32 is connected to a 64×64 LED matrix which is updated every second with a code for the current time. With single-second resolution that means that even with a method for reading a QR code by hand, like you sometimes can with barcodes, there’s no way to read it without a smartphone since it changes so rapidly.
Of course [Aaron] recognizes the flaw in his design in his video in which he notes tongue-in-cheek that with this clock you would never have to look at a smartphone again, since the clock is right there on the wall. We appreciate the humor and also that [Aaron] has made all of his source code available in case you would like to use this as an example project for using QR codes for more useful purposes. For now, though, we’ll just forward you along to some other useless machines.
Thanks to [willmore] for the tip!