What if you build a clock that displayed the time not just on its own, but in its shadows as well? [Lewis] from [DIY Machines] has done just that, with a nifty 3D-printed shadow clock build.

The clock itself has a hollow rim inside which are the two hands which actually display the time. The hands appear to almost float inside the clock, a tricky visual effect of the design which instantly catches the eye. The trick is simple—the minute hand is physically attached to the outer rotor, which sets its position. Meanwhile, the floating hour hand pivots freely around the center of the clock, with a secret magnet within. This magnet is attracted to a complementary magnet in the hour rotor—as that rotor turns, the hour hand points at the magnets inside.

So far, it’s already a cool clock. The bonus feature is that [Lewis] realized this design could show an even larger clockface on the wall behind, merely by using its shadows. Thus, the clock features an LED light source which can project the clock’s shadows into a much larger display than the desktop timepiece itself.

As for the electronics, it’s straightforward stuff. An ESP8266 devboard runs the show, turning stepper motors and controlling addressable LEDs to make the clock do its thing. It also queries a network time server in order to ensure the displayed time is always accurate to the second.

We’ve featured some other excellent clocks over the years, like this incredible thermochromic build. Video after the break.

It’s always clock time at Hackaday, and this time we have an interesting hack of a clock by [danjovic]– the CIS4, a Cistercian digital clock.

The Cistertians, in case you weren’t paying close attention to European holy orders during the 13th to 15th centuries were the group of monks you’d most likely have found us in. They were the hackers of the middle ages, establishing monestaries across western Europe that were chock full of hacks– including their own numeral system. Cistercian numerals were much more efficient (in spaces and penstrokes) than the Roman numerals they replaced, and even the “Arabic” numerals that replaced them. A single glyph could record anything from 1 to 9,999. (The Europeans hadn’t yet cottoned on to zero.)

Depending how you wanted to count time, a single glyph could be used; it looks like [danjovic] is using the thousands and hundreds portions of the glyph for hours and the tens and ones for minutes. This is all accomplished with a 4×4 neopixel matrix, run by an Attiny85 Digispark with a DS3231 RTC module keeping time. A slight simplification is required to reduce the glyphs to 4×4, but we don’t think the monks would mind. For those of us who don’t wear tonsures, an easy read mode scrolls the time in Arabic numerals. (Which still aren’t super easy,with only 4×4 LEDs to display them. See the demo video embedded below and try and guess the time.)

One nice quality of life feature is an LDR for ambient light detection, to automatically adjust the neopixels’ brightness. The hackiest part, which we thought was really clever, is the enclosure: it’s a cheap LED ceiling light. This provides a diffuser, housing and mounting hardware with decent design for no effort. A 3D-printed mask sits between the diffuser and the LEDs and doubles as a PCB holder. All very elegant.

[danjovic] did include a buzzer in the design, but does say if its been programed to sound off for matins, nones and vespers. In any case, at least it’s easier to read than his binary-coded-octal clock that we featured a few years back. This isn’t our first look at this number system,so evidently people can read them with practice.

Have you made or seen a cool clock? Send us a tip. We always have time for clocks.

It’s never a bad time to look at a clock, and one could certainly do worse than this delightful Paper Sunshine Clock by [anneosaur]. The sun-ray display is an interesting take on the analog clock, and its method of operation is not one we see every day, either.

Reading the clock is straightforward: there are twelve rays divided into two segments. Once you figure out that this artful object is a clock, it’s easy enough to guess that the rays give the hours, and half-rays are half-hours. In the photo above, it’s sometime between nine o’clock and nine thirty. Our Swiss readers might not be terribly impressed, but a “fuzzy” clock like this is quite good enough much of the time for many people.

The title gives away its method of operation: it’s thermochromic paint! The paint is printed onto a piece of Japanese awagami paper, which is pressed against a flexible PCB holding an array of resistors. Large copper pads act as heat spreaders for the resistors. For timekeeping and control, an Atmega328PB is paired with a DS3231MZ RTC, with a coin cell for backup power when the unit is unplugged. (When plugged in, the unit uses USB-C, as all things should.) That’s probably overkill for a +/-30 minute display, but we’re not complaining.

The Atmega328PB does not have quite enough outputs to drive all those resistors, so a multiplexing circuit is used to let the 10 available GIPO control current to 24 rays. Everything is fused for safety, and [anneosaur] even includes a temperature sensor on the control board. The resistors are driven by a temperature-compensated PWM signal to keep them from overheating or warming up too slowly, regardless of room temperature. The attention to detail here is as impressive as the aesthetics.

[annenosaur] has even thought of those poor people for whom such a fuzzy clock would never do (be they Swiss or otherwise) — the Paper Sunshine Clock has a lovely “sparkle mode” that turns the rays on and off at random, turning the clock into an art piece. A demo video of that is below. If you find this clock to be a ray of sunshine, everything you need to reproduce it is on GitHub under an MIT or CC4.0 license.

This is not the first thermochromic clock we’ve featured, though the last one was numeric. If you must have minute accuracy in a thermochromic analog clock, we’ve got you covered there, too.

Special thanks to [anneosaur] for submitting the hack. If you’ve seen (or made) a neat clock, let us know! You won’t catch us at a bad time; it’s always clock time at Hackaday.

Most of us spend our lives within reach of a device that provides a clock, stopwatch, and a timer – you’re almost certainly reading this article on such a device – but there are fewer options if you want a screen-free clock. [Michael Suguitan]’s TOKIDOKI rectifies this situation by combining those three functions into a single, physical, analog clock face.

More after the break…

TOKIDOKI displays time by lighting the appropriate segments of two concentric rings of colored LEDs (Adafruit Neopixel rings); the inner ring indicates hours, while the outer ring displays minutes. There is one clock hand, and while it does indicate the passage of time in some situations, its main function is as a dial to control the clock’s different functions. The hand is connected to a Dynamixel XL-330 servo motor, which also serves as a position sensor. Winding the dial clockwise starts a countdown timer, with each successive full rotation switching to a larger unit of time (a fun/unsettling feature is that the largest chronometric unit is the user’s expected lifetime: 84 years). Winding counterclockwise either starts a stopwatch or sets an alarm, depending on how many full rotations you make.

A Raspberry Pi Pico running some MicroPython firmware manages the device and gets the current time from a local network. To soften the light’s quality, the LED rings are pointed backwards to provide back-lighting off of a recessed surface. The entire device is powered by USB-C, and is enclosed in a 3D-printed housing.

This project was designed as an experiment in minimal interfaces, and it certainly achieved that goal, though we imagine that it takes a bit of time to get used to using this clock. We always enjoy seeing innovative clocks here, from digital to analogue, and those that split the difference.