Simulating A Time-Keeping Radio Signal

January 14, 2024 by Bryan Cockfield 14 Comments

As far as timekeeping goes, there’s nothing more accurate and precise than an atomic clock. Unfortunately, we can’t all have blocks of cesium in our basements, so various agencies around the world have maintained radio stations which, combined with an on-site atomic clock, send out timekeeping signals over the air. In the United States, this is the WWVB station located in Colorado which is generally receivable anywhere in the US but can be hard to hear on the East Coast. That’s why [JonMackey], who lives in northern New Hampshire, built this WWVB simulator.

Normally, clocks built to synchronize with the WWVB station include a small radio antenna to receive the 60 kHz signal and the 1-bit-per-second data transmission which is then decoded and used to update the time shown on the clock. Most of these clocks have internal (but much less precise) timekeeping circuitry to keep themselves going if they lose this signal, but [JonMackey] can go several days without his clocks hearing it. To make up for that he built a small transmitter that generates the proper timekeeping code for his clocks. The system is based on an STM32 which receives its time from GPS and broadcasts it on the correct frequency so that these clocks can get updates.

The small radio transmitter is built using one of the pins on the STM32 using PWM to get its frequency exactly at 60 kHz, which then can have the data modulated onto it. The radiating area is much less than a meter, so this isn’t likely to upset any neighbors, NIST, or the FCC, and the clocks need to be right beside it to update. Part of the reason why range is so limited is that very low frequency (VLF) radios typically require enormous antennas to be useful, so if you want to listen to more than timekeeping standards you’ll need a little bit of gear.

Making A Kit-Kat Clock Even Creepier

December 19, 2023 by Kristina Panos 10 Comments

If there’s anything as American as baseball and apple pie, it’s gotta be the Kit-Kat clock in the kitchen. For the unfamiliar, the Kit-Kat clock is special in that its pendulum tail and eyes move back and forth with each passing second. They’re equal parts cute and creepy.

But not this particular Kit-Kat, not once [Becky Stern] got a hold of it. The cute/creepy scales have been tipped, because the eyes of this Kat follow you around the room. “You” in this case is fellow maker [Xyla Foxlin], whom [Becky] drew in the Maker Secret Santa pool. See, [Xyla] loves cats, but is deathly allergic to them. So really, what better gift is there?

In order to make this happen, [Becky] started by disconnecting the long lever that link the eyes and the tail, which move together, and connected a servo horn to the eyes. [Becky] drilled out the nose in order to fit the camera, which is connected to a Seeed Grove AI Vision board with a Xiao RP2040 piggybacked on top.

While soldering on the servo wires, [Becky] accidentally detached a tiny capacitor from the AI Vision board, but it turns out that it wasn’t critical. Although she only had to write one line of code to get it to work, it ended up working too well, with the eyes darting around really quickly. By making the servo move in timed increments to the new positions, it’s now much more creepy. Be sure to check out the build video after the break.

You know we can’t resist a clock build around here, especially when those clocks are binary.

Continue reading “Making A Kit-Kat Clock Even Creepier” →

Monitoring Energy Use And Saving Money

November 29, 2023 by Bryan Cockfield 23 Comments

On the surface, the electric grid might seem like a solved piece of infrastructure. But there’s actually been a large amount of computerized modernization going in the background for the past decade or so. At a large scale this means automatic control of the grid, but for some electric utility customers like [Alex] this means the rates for electricity can change every hour based on demand. By keeping an eye on the current rate, you can extract the most value from these utilities.

[Alex] is located in the United Kingdom and has an energy provider whose rates can change every half hour. This information is freely available well enough in advance to download the data and display it visibly in with a NeoPixel LED ring around a clock. The colors displayed by the LEDs represent an increase or decrease in price for the corresponding time and allow him to better plan out the household’s energy use for the day. The clock uses a TinyPICO ESP32 module to gather the data and handle the clock display. A second wall-mounted device shows real-time energy readings for both gas and electricity using two old analog voltmeters modified to display kilowatt-hours.

While not everyone has a utility which allows this sort of granularity with energy pricing, having one can make a bit of a difference as electricity rates under this system can sometimes go negative. [Alex] estimates that using these two displays to coordinate his energy usage has saved around £50 a month. Even if your utility offers minimal or no price adjustments for time-of-use, it’s still a good idea to monitor energy use in your home. Here’s a fairly comprehensive project that does that without modifying any existing wiring.

Analog Wall Calendar Keeps Track Of The Days For You

November 23, 2023 by Lewin Day 4 Comments

[ssh16] had seen some fancy wristwatches with retrograde hands. Wanting to do something similar of their own, they set about creating an analog wall calendar that displays the date and the day of the week.

The build uses a pair of stepper motors to control the hands, a simple choice for accurate and reliable motion control. A Microchip PIC18F24J50 serves as the brains of the operation, chosen for its built-in RTC module and the fact that it has plenty of IO for controlling stepper motors. The built-in RTC is programmed with calendar information for the next 100 years, so there is no need to adjust the clock for leap years on the regular. The top hand of the wall calendar is driven in an arc to show days of the month, from 1 to 31. The bottom hand similarly steps through the 7 days of the week. If you’re unfamiliar with the concept of retrograde hands, they’re simply hands that sweep in an arc instead of moving in a whole continuous circle.

Hackers do love a good clock build, even if this one doesn’t specifically tell the time itself. If you’ve whipped up your own nifty timepiece, know that we’d love to see its fine face on the tipsline!

A Modernized Metric Clock

November 22, 2023 by Bryan Cockfield 60 Comments

Much to the chagrin of many living in North America who still need to do things like keep two sets of wrenches on hand, most of the rest of the world has standardized to a simpler measurement system using metric units exclusively. The metric system is widely adopted worldwide, but we still use a base-60 system for timekeeping that predates the rest of the metric system. The French did attempt to “decimalize” timekeeping as well with the French Republican Calendar at around this same time, but this “metric” timekeeping system never caught on particularly well. It’s still an interesting historical tidbit, and [ClassTech] built this modern metric clock to explore it a little more.

The system itself uses ten-day weeks, ten-hour days, and 100-minute hours which makes it more in line with the base-10 system common to the rest of the metric system. But this means that a second in the French Republican system actually works out to a little less than one and a half SI seconds, meaning that a modern timekeeping computer needs to do a little more math to display the correct time at the correct interval. [ClassTech] is using a Particle Photon IoT processor getting the time from a NTP server, converting it to “metric time”, and displaying the time on a Nextion touch display.

While the device is reported to update the time once per second, we’re not sure if this is every SI second or every French Republican second. Either way, there are plenty of reasons this timekeeping system never gained widespread adoption, and a surprising one is that timekeeping tends to be easier in a base-60 system due to its capability of having more divisors. Many other reasons are less technical and more cultural, and timekeeping tends to be surprisingly difficult to coordinate even among shared numbers systems and languages.

Don’t Look Up, Or You’ll See The Time From This VFD Projection Clock

November 15, 2023 by Dan Maloney 19 Comments

Ceiling clocks were a bit of a thing back in the days when clock radios were a fixture of nightstands. The idea was to project the time onto the ceiling so you’d only have to roll over onto your back and open your eyes to check the time, instead of potentially disturbing your slumber by craning your neck around to see the front of the clock.

As we recall, what sounded like a good idea was iffy in practice, with low-end optics and either weak incandescent bulbs or blazing LEDs. This nifty VFD projection clock by [Thomas Shupfs] seeks to fix those problems, and from the look of it does a pretty good job. It takes advantage of something else that fell out of favor with consumers — analog photography — by tapping into the ready supply of unwanted lenses. He paired that up with an IVL2-7/5 vacuum fluorescent display inside a 3D printed case with a cone-shaped extension to hold the lens at the right distance above the display. [Thomas] says that the STM32 software only supports JSON-RPC over USB at this time, and includes a couple of Python programs with examples of how to set the time and check the accuracy of the clock.

[Thomas] compares the clock head-to-head against his old LED projection clock, as seen in the featured image above; we flipped it for a better idea of what it would look like from bed. We’ve got to say the soft blue glow of the VFD would be a lot more pleasant to wake up to than the bright red LED projection. But this soft white projection clock is nice too.

Thanks to [skymab] for the tip.

Watch Time Roll By On This Strange, Spiral Clock

November 13, 2023 by Donald Papp 15 Comments

[Build Some Stuff] created an unusual spiral clock that’s almost entirely made from laser-cut wood, even the curved and bendy parts.

The living hinge is one thing, but getting the spacing, gearing, and numbers right also takes work.

The clock works by using a stepper motor and gear to rotate the clock’s face, which consists of a large dial with a spiral structure. Upon this spiral ramp rolls a ball, whose position relative to the printed numbers indicates the time. Each number is an hour, so if the ball is halfway between six and seven, it’s 6:30. At the center of the spiral is a hole, which drops the ball back down to the twelve at the beginning of the spiral so the cycle can repeat.

The video (embedded below) demonstrates the design elements and construction of the clock in greater detail, and of particular interest is how the curved wall of the spiral structure consists of a big living hinge, a way to allow mostly rigid materials to flex far beyond what they are used to. Laser cutting is well-suited to creating living hinges, but it’s a technique applicable to 3D printing, as well.

Thanks to [Kelton] for the tip!

Continue reading “Watch Time Roll By On This Strange, Spiral Clock” →