Power Sipping Master Keeps Slave Clock on Time

Few things are as infuriating as clocks that are not synchronized. It’s frustrating when the clock on the range and the clock on the microwave act like they’re in time zones that are one minute apart. Now picture that same issue over dozens of clocks in a train station, or hundreds in a school or factory. It’s no wonder that slave clocks, which advance on signals from a master clock, were developed.

When a pair of vintage Lepaute slave clocks made their way to [melka], he knew just what to do – build his own master clock to keep the slave on track. This particularly stylish slave clock uses pulses of alternating polarity every 30 seconds and will work on 1.5-volt pulses, which let [melka] meet his design goal of running for a year off a single AA battery. To keep the power needs low, [melka] relies on the RTC to wake up the MSP430 every second to increment a counter. When it hits 30, a pulse is sent to the clock’s motor through an H-bridge; the MCU alternates the polarity of every other pulse to advance the clock.

It’s not immediately clear how the clock is set; we recall the slave clocks in high school rapidly advancing for Daylight Saving adjustments, so we assume [melka] has provided some way of pulsing the clock quickly to set the time. Regardless, it’s a good lesson in low-power design. And be sure to check out this PIC-based master clock replacement, too.

Well Engineered Radio Clock Aces Form and Function

Clocks that read time via received radio signals have several advantages over their Internet-connected, NTP-synchronised brethren. The radio signal is ubiquitous and available over a fairly large footprint extending to thousands of kilometres from the transmitting antennae. This allows such clocks to work reliably in areas where there is no Internet service. And compared to GPS clocks, their front-end electronics and antenna requirements are much simpler. [Erik de Ruiter]’s DCF77 Analyzer/Clock is synchronised to the German DCF77 radio signal, which is derived from the atomic clocks at PTB headquarters. It features a ton of bells and whistles, while still being simple to build. It’s a slick piece of German hacker engineering that leaves us amazed.

Among the clock functions, it shows time, day of the week, date, CET/CEST modes, leap year indications and week numbers. The last is not part of the DCF77 protocol but is calculated via software. The DCF77 analyzer part has all of the useful information gleaned from the radio signals. There are displays for time period, pulse width, a bit counter, bit value indicator (0/1) and an error counter. There are two rings of 59 LEDs each that provide additional information about the DCF77 signal. A PIR sensor on the front panel helps put the clock in power save mode. Finally, there is a whole bunch of indicator LEDs and a bank of switches to control the various functions. On the rear panel, there are RJ45 sockets for the DCF77 receiver antenna board, temperature sensor and FTDI serial, a bunch of audio sound board controls, reset switches and a mode control switch.

His build starts with the design and layout of the enclosure. The front panel layout had to go through a couple of iterations before he was satisfied with the result. The final version was made from aluminium-coated sandwich-panel. He used an online service to photo-etch the markings, and then a milling machine to carve out the various windows and mounting holes. The rear panel is a tinted acrylic with laser engraving, which makes the neatly laid out innards visible for viewers to appreciate. The wooden frame is made from 40-year-old Mahogany, sourced from an old family heirloom desk. All of this hard work results in a really professional looking product.

The electronics are mostly off the shelf modules, except for the custom built LED driver boards. The heart of the device is an Arduino Mega because of the large number of outputs it provides. There are seven LED driver boards based around the Maxim 7221 (PDF) serial interface LED drivers – two to drive the inner and outer ring LEDs, and the others for the various seven-segment displays. The numerous annunciator LEDs are driven directly from the Arduino Mega. His build really comes together by incorporating a noise resilient DCF77 decoder library by [Udo Klein] which is running on a separate Arduino Uno. All of his design source files are posted on his GitHub repository and he hopes to publish an Instructable soon for those who would like to build one of their own.

In the first video below, he walks through the various functions of the clock, and in the second one, gives us a peek in to its inside. Watch, and be amazed.

Thanks for the tip, [Nick]

Continue reading “Well Engineered Radio Clock Aces Form and Function”

[Kwan]’s Clock Displays Seconds, and Thirds

We have no idea if the background story is true or not, but we’re not going to let something like “truth” get in the way of a good story. The way [Kwan3217] tells it, first there were hours on sundials. Then when these were divided into sixty minute sections, they were called “minutes”. “Seconds” comes from a second division by sixty, into “second minutes”. The “third” division into sixty would give a time unit that lasts a sixtieth of a second.

[Kwan3217] built a clock that displays these third minutes. Weighing in at just a tiny bit over 16.6666 milliseconds each, the thirds’ hand is going to be spinning pretty fast, so he used LEDs. And if you’re going to display thirds, you’ve got to get them right, so he backs the clock up with GPS. There’s a full video playlist about it, and phenomenal detail in the project logs. Continue reading “[Kwan]’s Clock Displays Seconds, and Thirds”

A Wordsearch Twist on the Word Clock

We love seeing new takes on existing ideas, and [Danny] certainly took the word clock concept in an unusual direction with his Wordsearch Clock. Instead of lighting up words to spell out the time, [Danny] decided to embrace the fact that the apparent jumble of letters on the clock face resembles a word search puzzle.

In a word search puzzle, words can be found spelled forward or backward with letters lined up horizontally, diagonally, or vertically. All that matters is that the correct letters are in a line and sequentially adjacent to one another. [Danny]’s clock lights up the correct letters and words one after the other, just as if it were solving a word search puzzle for words that just happen to tell the correct time. You can see it in action in the video, embedded below.

[Danny] went the extra mile in the planning phase. After using a word search puzzle generator tool to assist in designing the layout, he wrote a Processing sketch to simulate the clock’s operation. Visually simulating the clock allowed him to make tweaks to the layout, identify edge cases to address, and gain insight into the whole process. If you’re interested in making your own, there is a GitHub repository for the project.

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The Smartest Smart Watch is the One You Make Yourself

If you’re building a smart watch these days (yawn!), you’ve got to have some special sauce to impress the jaded Hackaday community. [Dominic]’s NeoPixel SmartWatch delivers, with his own take on what’s important to have on your wrist, and just as importantly, what isn’t.

There’s no fancy screen. Instead, the watch gets by with a ring of NeoPixels for all its notification needs. But notification is what it does right. It tells [Dominic] when he’s got an incoming call of course, but also has different flashing color modes for SMS, Snapchat, and e-mail. Oh yeah, and it tells time and even has a flashlight mode. Great functionality for a minimalistic display.

But that’s not all! It’s also got a light sensor that works from the UV all the way down to IR. At the moment, it’s being used to automatically adjust the LED brightness and to display current UV levels. (We imagine turning this into a sunburn alarm mode.) Also planned is a TV-B-Gone style IR transmitter.

The hardware is the tough part of this build, and [Dominic] ended up using a custom PCB to help in cramming so many off-the-shelf modules into a tiny space. Making it look good is icing on the cake.

Thanks [Marcello] for the tip!

Continue reading “The Smartest Smart Watch is the One You Make Yourself”

A Clock Created with Conway’s Life

Conway’s life has to be the most enduring zero-player computer game in history. Four simple cellular automaton rules have been used to create amazing simulations since the 1970’s. The latest is an entire digital clock implemented in life. StackExchange user [dim] created this simulation in response to a challenge from [Joe Z]. We have to admit that we didn’t believe it at first, but you can run it yourself by importing [dim’s] gist to the online Javascript Conway’s Life Simulator. To say this is impressive would be an understatement. We don’t know exactly how long it took [dim] to build this clock, but the challenge has been around since August of 2016.

[Dim] does a pretty good job of describing exactly how the clock works. The timebase is at the top. Below it is clock distribution and counters. After that come counters, latches, and lookup tables. Data moves around the clock in the form of gliders. P30 (aka Queen Bee) gliders to be exact. It might make things simpler to think of the glider paths as circuit traces, and the gliders themselves as clock pulses.

We couldn’t get over all the little details in this design. If you zoom way in, you can see all the lookup table patterns have been annotated, much in the way a schematic would be. For [Dim’s] next feat, we hope he takes on [Joe Z’s] Tetris challenge!

Conway’s life is like honey for hackers. We’ve seen it running on our own Hackaday Badge. We’ve even seen clocks that run the game on their display. Someone needs to implement a clock that runs the game that runs this clock. Clockception, anyone?

From 1950s Multimeter to Internet Connected Clock

We’ve seen many clocks here over the years. Some of them are conventional, some esoteric. So it’s not often that we see something novel in the world of timekeeping.

lael-450-analizzatore-hackedStrictly speaking, [Giulio Pons]’s clock project isn’t new at all. He’s taken a broken multimeter from the 1950s, and with the help of an Arduino Nano and an ESP8266 module, converted it into a clock that indicates the time on the multimeter’s moving-coil meter. He’s wired the multimeter’s front panel controls to the Arduino to operate the thing, and given it a speaker to play alarm sounds. A PIR motion detector activates the clock. In the hours of darkness, a photoresistor brings up a light. Time setting is automatic via the internet. [Giulio] previously experimented with an RTC module but found the network connection made changing time settings easier.

It’s by no means the perfect timepiece. For instance, [Giulio] found that driving the meter from a PWM pin gave different readings depending on the PSU load from other parts such as the light. But the clock does work, and has breathed new life into what might otherwise have remained a piece of junk.

Those of you with long memories might remember a similar project from a few years ago that used unmodified multimeters to display time as voltage. And of course, there are always frequency counter clocks.