Looking for an eye-catching and unique way to display the time and date? Want the flexibility to add other critical information, like the number of YouTube subs you’ve got? Care to be able to read it from half a block away, at least at night? Then this scrolling glow-in-the-dark dot-matrix display could be right up your alley.
Building on his previous Morse code transcriber using a similar display, [Jan Derogee] took the concept and went big. The idea is to cover a PVC pipe with phosphorescent tape and rotate it past a row of 100 UV LEDs. The LEDs are turned on as the glow-in-the-dark surface passes over them, charging up a row of spots. The display is built up to two rows of 16 characters by the time it rotates into view, and the effect seems to last for quite a while. An ESP8266 takes care of driving the display and fetching NTP time and YouTube stats.
We’ve seen “persistence of phosphorescence” clocks before, but not as good looking and legible as this one. We like the approach, and we can’t help but think of other uses for glow-in-the-dark displays.
Clocks are a recurring feature among the projects we feature here on Hackaday, with several common themes emerging among them. We see traditional clocks with hands, digital clocks with all forms of display including the ubiquitous Nixie tube, and plenty of LED ring clocks. [Matt Evans]’s build is one of the final category, a particularly nice LED ring clock using wire-ended multi-colour LEDs. Other clocks produce an effect that looks good from across the room, but this one is also a work of beauty when examined in close-up.
Behind it all are four interlocking semicircular PCBs, an STM32F051C6T6 ARM Cortex M0 microcontroller which controls the clock, and a brace of driver chips. The different “hands” of the clock are expressed as different LED colours, and there is a variety of different colour and clock “hand” effects. An acrylic ring completes the effect, by covering the LEDs themselves. He’s put together a video of the clock in action, which you can see below the break.
Like the look of Nixies but they just seem a little overdone? Or perhaps you just don’t want the hassles of a high-voltage power supply? Then maybe these faux-Nixie LED “tube” displays will find a way into your next clock build.
For his 2018 Hackaday Prize entry, [bobricius] decided that what the world needs is a Nixie that’s not a Nixie. To that end, each display is formed by seven surface-mount LEDs soldered to a seven-segment shaped PCB and slipped into a glass tube. The LEDs are in 4014 packages so they’re only 4 millimeters long, but what they lack in size they make up for in brightness. We’re not sure if it’s a trick of the camera, but the LEDs certainly seem to put off a bluish glow that’s reminiscent of vacuum-fluorescent displays — it’s like a Nixie and a VFD all rolled up in one package. The current case, which hides the clock circuitry on the lower part of the PCB, is just plastic, but this would look spiffy in a fine wooden case.
Revisiting old projects is always fun and this Nixie Clock by [pa3fwm] is just a classic. Instead of using transistors or microcontrollers, it uses neon lamps to clock and drive the Nixie Displays. The neon lamps themselves are the logic elements. Seriously, this masterpiece just oozes geekiness.
Inspired by the book “Electronic Counting Circuits” by J.B. Dance(ZIP), published in 1967, we covered the initial build a few years back. The fundamental concept of operation is similar to that of Neon Ring Counters. [Luc Small] has a write-up explaining the construction of such a device and some math associated with it. In this project, [pa3fwm] uses modern day neons that you find in indicators, so his circuit is also updated to compensate for the smaller difference in striking and maintaining voltages.
The original project was done in 2007 and has since undergone a few upgrades. [Pa3fwm] has modified the construction to make it wall mounted. Even though it’s not a precise timekeeper, the project itself is a keeper from its time. Check out the video below for a demonstration.
Reddit user [InThePartsBin] found some VFDs (Vacuum Fluorescent Displays) on an old PCB on eBay. The Russian boards date from 1987 and have a bunch of through-hole resistors, transistors and a some mystery ICs, plastic wraps around the legs and the top of the tube is held steady by a rubber grommet (the tip itself goes through a hole in a board mounted perpendicular to the main board.) Being the curious kind of person we like, and seeing the boards weren’t too expensive, he bought some in order to play around with to see if he could bring them back to life.
After getting the VFDs lighting up and figuring out the circuitry on the back, [InThePartsBin] decided that a clock was the best thing to build out of it. It was decided that a specialized VFD driver chip was the easiest way to make the thing work, so a MAX6934 was ordered. To give the clock some brains, an ATmega328 was recruited and to keep time, [InThePartsBin] had some DS3231 real-time clock modules left over from a previous project, so they were recruited as well. A daughterboard was designed to sit on the back of the vintage board and hold the ‘328 and the VFD driver chip.
Once [InThePartsBin] soldered on the components it was time to fire it up and send 1’s to the driver to turn on all the segments on all the tubes. Success! The only thing that [InThePartsBin] has left to do is write the code for the clock, but all the segments and tubes are controllable now, so the hardware part is done. There are other VFD clock projects on the site: Check out this one, or this one, and bask in the beautiful steel-blue glow.
What is it about mechanical clocks? Maybe it’s the gears, or the soft tick-tocking that they make? Or maybe it’s the pursuit of implausible mechanical perfection. Combine mechanical clocks with “free” energy harvested from daily temperature and pressure variation, and we’re hooked.
Both the Beverly Clock, built by Arthur Beverly in 1864, and the Atmos series of clocks built between 1929 and 1939, run exclusively on the expansion and contraction of a volume of air (Beverly) or ethyl chloride (Atmos) over the day to wind up the clock via a ratchet. The Beverly Clock was apparently a one-off, and it’s still running today. And with over 500,000 Atmos clocks produced, there must be some out there.
Although we had never heard of it, this basic idea is really old. Clicking through Wikipedia (like you do!) got us to Cox’s Timepiece, which is powered by the movement of 68 kg of mecury under atmospheric pressure. It is currently not running, but housed in the Victoria and Albert Museum in London. Even older is a clock that we couldn’t find any info on that dates from 1620, invented by Cornelius Drebbel. Anyone know anything?
We’ve had energy harvesting on our mind lately, and the article on the Beverly Clock says that it gets 31 μWh over a day when the temperature swings by 3.3 °C. Put into microcontroller perspective, this is 0.39 μA at 3.3 V, so you’ll have to be pretty careful about your sleep modes, and an LED is out of the question. How amazing is it, then, that this can power a mechanical clock?
Thanks [Luke], [hex4def6], and [Wallace Owen] for tipping us off to these in the comment section!
Persistence of vision displays are fun, and a natural for clocks, but they’re getting a little Nixie-ish, aren’t they? There are only so many ways to rotate LEDs and light them up, after all. But here’s something a little different: a POP, or “persistence of phosphorescence” clock.
[Chris Mitchell] turned the POV model around for this clock and made the LEDs stationary, built into the tower that holds the slowly rotated display disk. Printed from glow-in-the-dark PLA, the disk gets charged by the strip of UV LEDs as it spins, leaving behind a ghostly dot matrix impression of the time. The disk rotates on a stepper, and the clock runs on a Nano with an RTC. The characters almost completely fade out by the time they get back to the “write head” again, making an interesting visual effect. Check it out in the video after the break.
Our only quibble is the choice to print the disk rather than cut it from sheet stock. Seems like there has to be commercially available phosphorescent plastic, or even the glow-in-the-dark paper used for this faux LED scrolling sign. But if you’ve got glowy PLA, why not use it?