We’re not sure if [Derek Lieber] is messing with us or proving a point. Why are you doing this [Derek]? We know there’s technically enough information to build the clock. You even included the code. Couldn’t you have at least thrown in a couple of words? Do we have to skip straight to mediaglyphics?
Anyway, if we follow the equation. The equation… If you take a gps module, a 7 segment display with an HT16K33 backpack, a digital potentiometer, a piezo, and a boarduino we suppose we could grudgingly admit that these would all fit together to make a clock. We still don’t like it though, but we’ll admit that the nice handmade case was a nice touch, and that the pictures do give us enough details to do it ourselves.
It was also pretty cool when you added the Zelda theme song as an alarm sound. Also pretty neat that, being GPS corrected, there’s no need to ever set the time. We may also like the simplicity of the only inputs being the potentiometer, which is used to set the alarm time. It’s just. Dangit [Derek]. Nice clock build, we like it.
For this clock, one of the many custom builds on [GMG]’s site that betray a certain passion for unusual timepieces, an 8×32 array of Neopixels lives behind a laser-cut sheet of steam-bent birch plywood. Each pixel is masked by either an alphanumeric character or an icon representing weather conditions. An ESP8266 fetches time and weather data and drives the display serially, controlling the color of each cell and building up the display. The video below shows the clock doing its thing.
Sure, we’ve featured plenty of word clocks before, even some with weather display, but we like the slim and understated design of this build. We’re particularly impressed by the lengths [GMG] took in packing as much capability into the 256-pixel display as possible, like the way “today” and “tomorrow” overlap. And if you’ve got an eye for detail, you might spot what gets displayed when it’s over 80° and 80% relative humidity.
The clock itself is very attractive. If you look closely you can see the circuitry backlit behind the dot LED matrix display. The whole thing is housed in a nicely folded steel case. RGB LEDs are used to good effect to highlight some additionally obfuscating circuit schematics. The workmanship is very top notch, and we would gladly host such an object on our desks.
The clock’s standard time telling mode is three sets of square waves showing the binary values for the hours, minutes, and seconds. Every now and then the clock will glitch out. The waves will distort. The colors will change. And every now and then, tantalizingly, the alpha-numeric time will show up for just a split second, before returning to those weird squiggles again.
We’ve seen a whole slew of binary clocks before. This one, for instance. But the waveform display makes us feel just that little bit more at home — it’s just like we’re sitting in front of our oscilloscope.
Until the 1960s, watches and clocks of all kinds kept track of time with mechanical devices. Springs, pendulums, gears, oils, and a whole host of other components had to work together to keep accurate time. The invention of the crystal oscillator changed all of that, making watches and clocks not only cheaper, but (in general) far more accurate. It’s not quite as easy to see them in action, however, unless you’re [noq2] and you have a set of strobe lights.
[noq2] used a Rigol DG4062 function generator and a Cree power LED as a high-frequency strobe light to “slow down” the crystal oscillators from two watches. The first one he filmed was an Accutron “tuning fork” movement and the second one is a generic 32,768 Hz quartz resonator which is used in a large amount of watches. After removing the casings and powering the resonators up, [noq2] tuned in his strobe light setup to be able to film the vibrations of the oscillators.
It’s pretty interesting to see this in action. Usually a timekeeping element like this, whether in a watch or a RTC, is a “black box” of sorts that is easily taken for granted. Especially since these devices revolutionized the watchmaking industry (and a few other industries as well), it’s well worthwhile to take a look inside and see how they work. They’re used in more than just watches, too. Want to go down the rabbit hole on this topic? Check out the History of Oscillators. Continue reading “Strobe Light Slows Down Time”→
Building a video projector isn’t something that most people do casually, but [Dominic Buchstaller] isn’t most people. As part of an ongoing street art project, he built a rather neat scrap video projector/bedside lamp/clock device he calls Great Balls of Fire. It is made from a Nokia cell phone screen and a small projector mechanism, mounted inside a frosted glass light sphere.
One of the most interesting parts of the build is the projector mechanism. Rather than build one from scratch or tear apart an expensive Pico projector, [Dominic] found another source: a cheap car logo projector from eBay. These are designed to show a car manufacturer logo on the ground when you open your car door. It came with all of the parts he needed, including an LED light source and optics. He tore that apart and replaced the car logo with the phone screen, creating a very cheap projector. It isn’t that bright, but it is bright enough that when he mounted it inside the glass sphere, it could project the time and the odd space invader. It’s a great example of how sometimes it makes sense to look for a cheap solution rather than a free one: buying the car logo projector saved him a lot of hassle in building the optics. [Dominic] was also responsible for this awesome old-school tube radio hack, where he replaced the guts of an old radio with an internet radio player.
A lot of microcontroller projects out there need some sense of wall-clock time. Whether you’re making (yet another) crazy clock, logging data, or just counting down the time left for your tea to steep, having access to human time is key.
The simplest solution is to grab a real-time-clock (RTC) IC or module. And there’s good reason to do so, because keeping accurate time over long periods is very hard. One second per day is 1/86,400 or around eleven and a half parts per million (ppm), and it’s tricky to beat twenty ppm without serious engineering.
Good RTC ICs like Maxim’s DS3231, used in the Chronodot, can do that. They use temperature correction logic and a crystal oscillator to get as accurate as five parts per million, or under half a second per day. They even have internal calendar functions, taking care of leap years and the day of the week and so on. The downside is the cost: temperature-compensated RTCs cost around $10 in single quantity, which can break the budget for some simple hacks or installations where multiple modules are needed. But there is a very suitable alternative.
What we’re looking for is a middle way: a wall-time solution for a microcontroller project that won’t break the bank (free would be ideal) but that performs pretty well over long periods of time under mellow environmental conditions. The kind of thing you’d use for a clock in your office. We’ll first look at the “obvious” contender, a plain-crystal oscillator solution, and then move on to something experimental and touchy, but free and essentially perfectly accurate over the long term: using power-line frequency as a standard.
It seems that the longer a technology has been around, the more likely it is that all of the ideas and uses for that technology will be fleshed out. For something that’s been around for around 5500 years it must be especially rare to teach an old dog new tricks, but [Sebastian] has built a sundial that’s different from any we’ve ever seen.
Once done with all of the math for the sundial to compute its angles and true north based on his latitude and longitude, [Sebastian] used Autodesk Inventor to create a model. From there it was 3D printed, but the interesting part here is that the 3D printer allowed for him to leave recesses for numbers in the sundial. The numbers are arranged at such angles inside the sundial so that when it’s a particular hour, the number of the hour shines through the shadow of the sundial which creates a very unique effect. This would be pretty difficult to do with any machine tools but is easily accomplished via 3D printing.
[Sebastian] wanted a way to appreciate the beauty of time, and he’s certainly accomplished that with this new take on the sundial! He also wonders what it would be like if there was a giant one in a park. This may also be the first actual sundial build we’ve featured. What does that mean? Check out this non-pv, sun-powered clock that isn’t a sundial.