NTP Projection Clock

thingiverse

These are the chassis components to a digital clock, synchronized over your wifi to a standard NTP server, that projects the time onto a wall or ceiling. I built this because I had one of those junky digital clocks that purports to "automatically synchronize to an atomic clock in Colorado", and naturally, it never worked. Turns out Colorado is pretty far away from almost everyone. Even people in Colorado. But that's ok, because we have this neat thing called the Internet now. And every computer and their grandma knows how to get a very accurate time from a standard NTP server. So I bought a small cheap wireless NodeMCU wifi embeddded compuer, wired it to a simple 4 digit display, and coded it to find the time, and activate the display appropriately. The one rub is that the display actually has to be inverted, because in order to project the time against a wall, you need to shine it through a magnifying glass at a specific distance, and while the magnifying glass refracts the image well, it also inverts it. So to get a readable time, you have to pre-invert it so the digits shown are non-inverted. I was originally planning to model it with a complex pan and tilt mechanism adjusted by worm screws, which is why you see an unused ring gear around the main body. But I realized that was design overkill, as a fixed 45 degree angle was good for 99% of use cases. You can find further docs and source code at https://github.com/chrisspen/ntp-clock-projector