You’ve probably seen autostereogram images in Magic Eye books or elsewhere, which hide images behind a seemingly random pattern of dots until you focus correctly. These are certainly a fun and/or frustrating distraction, but you’ve probably never considered embedding dynamic content on this type of image, as David Johnson-Davies’ did in his latest Technoblogy build.
Instead of static images, his Magic 3D Clock setup uses a small TFT screen to reveal the time once you’ve focused correctly. Personally, I’ve yet to get it to show up — though his first write-up image supposedly says 12:45 — making it seemingly more interesting than useful. As he puts it though, “It’s ideal if you don’t want to be constantly reminded of the time, but want to be able to check it when you need it,” giving it a surprisingly practical justification… not that it needs one!
Build-wise, the device is constructed on a small breadboard, using an ATtiny85 for control, with a DS1302 RTC module to help it keep track of time. The autosterograms are shown on a 1.8” ST7735 160×128 TFT screen, so not terribly unusual hardware-wise. What is interesting, however, is Davies’ discussion about how the program works, drawing random color textures, and hiding four digits inside that trick your eyes into seeing the correct time. Perhaps we’ll see more clocks made like this in the future, or any number of semi-obscured data displays, open to those with the patience and eye-focusing ability to find the needed info!