This Thermochromic Clock Is A Ray Of Sunshine

June 16, 2025 by Tyler August 5 Comments

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.

Even the flex PCB holding the resistors looks like a work of art.

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.

A clock face is shown consisting of two rings of plastic, with backlighting behind one of the rings. There is red light at the one o’clock position, and blue light at the nine-thirty position. A black plastic arm is pointing to the three-thirty position.

A Concentric Clock With Multiple Modes

June 14, 2025 by Aaron Beckendorf No comments

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.

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. Continue reading “A Concentric Clock With Multiple Modes” →

A Close Look At The Mitxela Precision Clock Mk IV

June 8, 2025 by John Elliot V 15 Comments

Over on his secondary YouTube channel, [Jeff Geerling] recently demoed the new Mitxela Precision Clock Mk IV.

This clock uses GPS to get the current time, but also your location so it can figure out what time zone you’re in and which daylight savings time might apply. On the back a blinking diode announces the arrival of each second. A temperature-compensated crystal oscillator (TCXO) is employed for accurate time-keeping.

The clock can be folded in half, thereby doubling as a clapperboard for movie makers. The dimming system is analog, not pulse width modulation (PWM), which means no visible flashing artifacts when recording. It is highly configurable and has USB connectivity. And it has not one but two ARM microcontrollers, an ARM STM32L476, and an ARM STM32L010. If you’re interested, you can pick one up for yourself from [Mitxela]’s shop.

Toward the end of his video [Jeff] does some navel gazing, thinking about what might be required if future versions of the clock wanted to get down into precision at the nanosecond level. Do you arrange it so the light arrives at the viewer’s eyeball at the right time? Or do you update it on the clock at the right time and let the viewer know about it after a minuscule delay? Philosophical preponderances for another day!

We should add that we’ve seen plenty of cool stuff from [Mitxela] before, including the Euroknob and these soldering tweezers.

Continue reading “A Close Look At The Mitxela Precision Clock Mk IV” →

A woman in a richly-colored blue head scarf leans over a wooden table looking at the timer between her hands. The timer has a yellow circle on black flip panels on the left and black and white CT scans of a human torso on the right side. The frame is wood, and there is an electric motor on the upper right of the frame and a silver drum on the left of the frame beneath the woman's hand.

A Flip Clock Becomes A Flip Timer

June 6, 2025 by Navarre Bartz 3 Comments

Sometimes it’s nice to have a widget to do a single task and avoid getting distracted by the supposed simplicity of doing it with an app on a smartphone. [Dina Amin] built a timer from an old flip clock to stay focused.

Starting with a disassembly of the flip clocks she found at a flea market with [Simone Giertz], [Amin] decided to change the twenty four hour mechanism to a twenty four minute one which was similar to the amount of time she was already using for several different practices. Since she’s an expert in animation, she planned on turning a set of CT scans into the animation that would play on the section that had previously been the minutes of the clock.

As much of the original clock’s components were damaged, and [Amin] didn’t have a chance to learn clockmaking from scratch in a week, she tried a few different drive mechanisms for the build. The drum from an air fryer timer driven with an electric motor fit the bill, but off enough from proper minutes that [Amin] switched from numerals to a yellow circle that fills in as it approaches the satisfying ding of completion.

If you want to see Simone’s Moon flip clock we’ve covered that project too.

Continue reading “A Flip Clock Becomes A Flip Timer” →

A woman in a ball cap and black tank top holds a black and white image of the Moon printed on black acrylic. It can fold and is mounted on a black plastic mechanism with turning knobs affixed to the ends. There are out-of-focus shelves in the background with various items and books on them.

Moon Phase Flip Clock Is Fantastic

May 16, 2025 by Navarre Bartz 15 Comments

We love clocks, but we especially love unusual timepieces that aren’t just about showing the hour of the day. [Simone Giertz] built a flip clock moon phase tracker for a friend.

While in Egypt for Cairo Maker Faire, [Giertz] and [dina Amin] found some old flip clocks at a flea market and had to have them. [Amin] mentioned wanting to make a moon phase tracker with one, and [Giertz] decided to try her hand at making her own version. A side quest in more comfortable flying is included with the price of admission, but the real focus is the process of figuring out how to replicate the flip clocks original mechanism in a different size and shape.

[Giertz] cut out 30 semi-circle flaps from polystyrene and then affixed vinyl cut-outs to the flaps. The instructions for the assembly suggest that this might not be the best way to do it, and that printing stickers to affix to the flaps might work better since the cut vinyl turned out pretty fiddly. We really like the part where she built a grid jig to determine the optimal placement of the beams to keep the flaps in the right position after a disheartening amount of difficulties doing it in a more manual way. Her approach of letting it rest for twenty minutes before coming back to it is something you might find helpful in your own projects.

Best of all, if you want to build your own, the files are available for the flip moon station on the Yetch website. You’ll have to come up with your own method to drive it though as that isn’t in the files from what we saw.

Continue reading “Moon Phase Flip Clock Is Fantastic” →

A Neat E-Paper Digit Clock (or Four)

May 2, 2025 by Lewin Day 3 Comments

[sprite_tm] had a problem. He needed a clock for the living room, but didn’t want to just buy something off the shelf. In his own words, “It’s an opportunity for a cool project that I’d rather not let go to waste.” Thus started a project to build a fun e-paper digit clock!

There were several goals for the build from the outset. It had to be battery driven, large enough to be easily readable, and readily visible both during the day and in low-light conditions. It also needed to be low maintenance, and “interesting,” as [sprite_tm] put it. This drove the design towards an e-paper solution. However, large e-paper displays can be a bit pricy. That spawned a creative idea—why not grab four smaller displays and make a clock with separate individual digits instead?

The build description covers the full design, from the ESP32 at the heart of things to odd brownout issues and the old-school Nokia batteries providing the juice. Indeed, [sprite_tm] even went the creative route, making each individual digit of the clock operate largely independently. Each has its own battery, microcontroller, and display. To save battery life, only the hours digit has to spend energy syncing with an NTP time server, and it uses the short-range ESPNow protocol to send time updates to the other digits.

It’s an unconventional clock, to be sure; you could even consider it four clocks in one. Ultimately, though, that’s what we like in a timepiece here at Hackaday. Meanwhile, if you’ve come up with a fun and innovative way to tell time, be sure to let us know on the tipsline!

[Thanks to Maarten Tromp for the tip!]

Back To Reality With The Time Brick

April 29, 2025 by Bryan Cockfield 8 Comments

There are a lot of distractions in daily life, especially with all the different forms of technology and their accompanying algorithms vying for our attention in the modern world. [mar1ash] makes the same observation about our shared experiences fighting to stay sane with all these push notifications and alerts, and wanted something a little simpler that can just tell time and perhaps a few other things. Enter the time brick.

The time brick is a simple way of keeping track of the most basic of things in the real world: time and weather. The device has no buttons and only a small OLED display. Based on an ESP-01 module and housed in a LEGO-like enclosure, the USB-powered clock sits quietly by a bed or computer with no need for any user interaction at all. It gets its information over a Wi-Fi connection configured in the code running on the device, and cycles through not only time, date, and weather but also a series of pre-programmed quotes of a surreal nature, since part of [mar1ash]’s goals for this project was to do something just a little bit outside the norm.

There are a few other quirks in this tiny device as well, including animations for the weather display, a “night mode” that’s automatically activated to account for low-light conditions, and the ability to easily handle WiFi drops and other errors without crashing. All of the project’s code is also available on its GitHub page. As far as design goes, it’s an excellent demonstration that successful projects have to avoid feature creep, and that doing one thing well is often a better design philosophy than adding needless complications.