X Marks the Clock

There’s no shortage of Arduino-based clocks around. [Mr_fid’s] clock, though, gets a second look because it is very unique looking. Then it gets a third look because it would be very difficult to read for the uninitiated.

The clock uses three Xs made of LEDs. There is one X for the hours (this is a 24-hour clock), another for the minutes, and one for the seconds. The left side of each X represents the tens’ digit of the number, while the right-side is the units.

But wait… even with two segments on each side of the X, that only allows for numbers from 0 to 3 in binary, right? [Mr_fid] uses another dimension–color–to get around that limitation. Although he calls this a binary clock, it is more accurately a binary-coded-decimal (BCD) clock. Red LEDs represent the numbers one to three. Green LEDs are four to six. Two blue segments represent seven to nine. It sounds complicated, but if you watch the video, below, it will make sense.

This isn’t [Mr_fid’s] first clock. He is using a DS1307 real time clock module to make up for the Arduino’s tendency to drift. Even if you aren’t interested in the clock, the mounting of the LEDs with plastic–and the issues he had isolating them from each other–might come in handy in other displays.

We’ve seen a lot of Arduino clocks over the years, including some that talk. We’ve even seen some that qualify as interactive furniture, whatever that is.


Filed under: Arduino Hacks, clock hacks

Micro Radio Time Station Keeps Watch in Sync

The US National Institute of Standards and Technology (NIST) broadcasts atomic clock time signals from Fort Collins, Colorado on various frequencies. The WWVB signal on 60 kHz blasts out 70,000 watts that theoretically should reach the entire continental US. Unfortunately for [Anish Athalye], the signals do not reach his Massachusetts dorm, so he built this GPS to WWVB converter to keep his Casio G-Shock self-setting watch on track.

Not a repeater but a micro-WWVB transmitter, [Anish]’s build consists of a GPS receiver module and an ultra low-power 60kHz transmitter based on an ATtiny44a microcontroller’s hardware PWM driving a ferrite rod antenna. It’s not much of a transmitter, but it doesn’t need to be since the watch is only a few inches away. That also serves to keep the build in compliance with FCC regulations regarding low-power transmissions. Heavy wizardry is invoked by the software needed to pull time data off the GPS module and convert it to WWVB time code format, with the necessary time zone and Daylight Savings Time corrections. Housed in an attractive case, the watch stand takes about three minutes to sync the watch every night.

[Anish] offers some ideas for improving the accuracy, but we think he did just fine with this build. We covered a WWVB signal spoofer before, but this build is far more polished and practical.


Filed under: clock hacks, radio hacks

Set Your Clocks to Decimal Time

Many stop lights at street intersections display a countdown of the remaining seconds before the light changes. If you’re like me, you count this time in your head and then check how in sync you are. But did you know that if the French had their way back in the 1890s when they tried to introduce decimal time, you’d be counting to a different beat? Did you know the Chinese have used decimal time for millennia? And did you know that you may have unknowingly used it already if you’ve programmed in Linux? Read on to see what decimal time is along with the answers to these questions.

How We Got Where We Are

Babylonian numerals
Babylonian numerals, By Jose117 [CC BY-SA 4.0], via Wikimedia Commons
First off, just why do we have 60 seconds, 60 minutes and 24 hours in a day? The 24 hour day started with the Egyptians breaking the number of daylight hours into 12. One possible reason for using 12 is that it’s the number of segments we have separated by knuckles on the four fingers of each hand. Notice how easily you can count them using your thumbs, something you should be comfortable with in these days of thumb-manipulated mobile phones.

The use of 60 minutes in an hour and 60 seconds in a minute didn’t come into everyday use until the invention of mechanical clocks in the 16th century. Prior to that their use just wasn’t practical. The selection of 60 for the divisions stems ultimately from the Sumerians with their sexagesimal (base 60) number system, though it’s difficult to find just when they were chosen for the units of time. The words minute and second come from the latin pars minuta prima, which means “first small part”, and pars minuta secunda, or “second small part”.

The second was for a long time defined to be 1/86400 of a mean solar day (60*60*24 = 86400). It was recently defined more precisely as “the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium 133 atom”.

But as you can see above, though necessary and useful, all our units were derived from fairly arbitrary sources and are of arbitrarily selected lengths.

Metric Time Vs Decimal Time

Before getting into decimal time, we should clear up what we mean by metric time, since the two are often used incorrectly. Metric time is for measurement of time intervals. We’re all familiar with these and use them frequently: milliseconds, microseconds, nanoseconds, and so on. While the base unit, the second, has its origin in the Sumerian base 60 number system, it is a metric unit.

Decimal time refers to the time of day. This is the division of time using base 10 instead of dividing the day into 60, 60 and 24.

French Decimal Time

French decimal time clock
French decimal time clock, By Cormullion, Own work [CC BY-SA 3.0], via Wikimedia Commons
There were a few attempts in France to switch to decimal time. The first began use in 1794 during the French Revolution (1789-1799). They divided the day into 10 hours, each hour being 100 minutes long, and each minute containing 100 seconds.

This allowed for time to be written as we would, 2:34 for 2 hours and 34 minutes, but also as the decimal numbers 2.34 or even 234. For timestamping purposes we’d write 2016-12-08.234. We could also write it as the fraction 0.234 of the day or written as a percentage, 23.4% of the day. The seconds can simply be added on as an additional 2 digits.

That’s certainly simpler than what we currently have to do with our standard system. To convert 2:34 AM to a single number representing the duration of the day in minutes we have to do:

(2 hours*60 min/hour)+34 min=154 minutes

As a fraction of the day it’s:

154 min/(60 min/hour * 24 hours)=0.1069

And finally, 0.1069 as a percentage is 10.69%. Summarizing, that’s the time 2:34 AM represented as 154 minutes, 0.1069, and 10.69%. You can hardly blame the French for trying. Vive la revolution!

Decimal time went into official use in France on September 22, 1794 but mandatory use ended April 7, 1795, giving it a very short life. Further attempts were made in the late 1800s but all failed.

Swatch Beat watch
Swatch Beat watch

If you do the math, each hour in the French decimal system was 144 conventional minutes long, each minute was 86.4 conventional seconds and each second was 0.864 conventional seconds. If you can get used to an hour that’s twice as long, probably not too difficult a feat, the minutes and seconds are reasonably close to what we’re used to. However, science uses the second as the base of time and that’s a huge amount of momentum to overcome.

Incidentally, in 1998, as part of a marketing campaign, the Swatch corporation, a Swiss maker of watches, borrowed from the French decimal time by breaking the day into 1000 ‘.beats’. Each .beat is of course 86.4 seconds long. For many years they manufactured watches that displayed both standard time and .beat time, which they also called Internet Time.

Chinese Decimal Time

China has as long and varied a history as that of the West, and for over 2000 years, China used decimal time for at least one unit of its time system. They had a system where the day was divided into 12 double hours, but also a system dividing it into 100 ke. Each ke was further divided into either 60 or 100 fen at different times in its history.

Fractional Days

But decimal time is in use today. The fractional day is also a form of decimal time and is used in science and in computers. The time of day is expressed as the conventional 24 hour time but converted to a fraction of the day. For example, if time 0 is 12:00 midnight, 2:30 AM is:

((2*3600 sec/hour) + 30*60 sec/min) / 86400 sec/day = 0.10417

As many decimal places as needed can be used.

One example where fractional days are used is by astronomers for Julian days. Julian days are solar days in decimal form with 0 being noon Universal time (UT) at the beginning of the Julian calender, November 24, 4717 BC. For example, 00:30:00 UT January 1, 2013 as a Julian date is 2,456,293.520833.

Microsoft Excel also uses fractional days within dates similar to Julian dates but called serial dates. The time of day is stored as a decimal fraction of the 24 hours clock starting from midnight.

Unix/Linux Time

We may be repulsed by the idea of switching to an unfamiliar decimal time in our daily lives but many of us have used it when calling the time() function in Unix variations such as Linux. This function returns the current time in seconds since the beginning of some epoch. The Unix epoch began on 0:00:00 UTC January 1, 1970, a Thursday. But at least those seconds are of the length we’re used to — no need to resynchronize our internal counter there.

Vive La Revolution!

But while the French revolution is in the past, rebels do exist here at Hackaday. [Knivd] is one such who has devised a decimal time called C10 that’s slightly different from the French’s. And he already has at least one fellow conspirator, [Danjovic], who’s already made a decimal clock called DC-10. How long before we’re all counting to the beat of a different drum, and crossing those intersections before the light has changed?


Filed under: clock hacks, Featured, Interest

Arduino Clock Is HAL 1000

In the movie 2001: A Space Odyssey, HAL 9000 — the neurotic computer — had a birthday in 1992 (for some reason, in the book it is 1997). In the late 1960s, that date sounded impossibly far away, but now it seems like a distant memory. The only thing is, we are only now starting to get computers with voice I/O that are practical and even they are a far cry from HAL.

[GeraldF6] built an Arduino-based clock. That’s nothing new but thanks to a MOVI board (ok, shield), this clock has voice input and output as you can see in the video below. Unlike most modern speech-enabled devices, the MOVI board (and, thus, the clock, does not use an external server in the cloud or any remote processing at all. On the other hand, the speech quality isn’t what you might expect from any of the modern smartphone assistants that talk. We estimate it might be about 1/9 the power of the HAL 9000.

You might wonder what you have to say to a clock. You’ll see in the video you can do things like set and query timers. Unlike HAL, the device works like a Star Trek computer. You address it as Arduino. Then it beeps and you can speak a command. There’s also a real-time clock module.

Setting up the MOVI is simple:

 recognizer.init(); // Initialize MOVI (waits for it to boot)
 recognizer.callSign("Arduino"); // Train callsign Arduino (may take 20 seconds)
 recognizer.addSentence(F("What time is it ?")); // Add sentence 1
 recognizer.addSentence(F("What is the time ?")); // Add sentence 2
 recognizer.addSentence(F("What is the date ?")); // Add sentence 3
...

Then a call to recognizer.poll will return a numeric code for anything it hears. Here is a snippet:

// Get result from MOVI, 0 denotes nothing happened, negative values denote events (see docs)

 signed int res = recognizer.poll(); 

// Tell current time
 if (res==1 | res==2) { // Sentence 1 & 2
 if ( now.hour() > 12) 
 recognizer.say("It's " + String(now.hour()-12) + " " + ( now.minute() < 10 ? "O" : "" ) +
     String(now.minute()) + "P M" ); // Speak the time
...

Fairly easy.

HAL being a NASA project (USSC, not NASA, and HAL was a product of a lab at University of Illinois Urbana-Champaign – ed.) probably cost millions, but the MOVI board is $70-$90. It also isn’t likely to go crazy and try to kill you, so that’s another bonus. Maybe we’ll build one in a different casing. We recently talked about neural networks improving speech recognition and synthesis. This is a long way from that.


Filed under: Arduino Hacks, clock hacks

For Your Binge-Watching Pleasure: The Clickspring Clock Is Finally Complete

It took as long to make as it takes to gestate a human, but the Clickspring open-frame mechanical clock is finally complete. And the results are spectacular.

If you have even a passing interest in machining, you owe it to yourself to watch the entire 23 episode playlist. The level of craftsmanship that [Chris] displays in every episode, both in terms of the clock build and the production values of his videos is truly something to behold. The clock started as CAD prints glued to brass plates as templates for the scroll saw work that roughed out the frames and gears. Bar stock was turned, parts were threaded and knurled, and gear teeth were cut. Every screw in the clock was custom made and heat-treated to a rich blue that contrasts beautifully with the mirror polish on the brass parts. Each episode has some little tidbit of precision machining that would make the episode worth watching even if you have no interest in clocks. For our money, the best moment comes in episode 10 when the bezel and chapter ring come together with a satisfying click.

We feature a lot of timekeeping projects here, but none can compare to the Clickspring clock. If you’re still not convinced, take a look at some of our earlier coverage, like when we first noticed [Chris]’ channel, or when he fabricated and blued the clock’s hands. We can’t wait for the next Clickspring project, and we know what we’re watching tonight.


Filed under: clock hacks, misc hacks

These Sands Of Time Literally Keep Time

Hour glasses have long been a way to indicate time with sand, but the one-hour resolution isn’t the best. [Erich] decided he would be do better and made a clock that actually wrote the time in the sand. We’ve seen this before with writing time on a dry erase board with an arm that first erases the previous time and then uses a dry erase marker to write the next time. [Erich]’s also uses an arm to write the time, using the tip of a sea shell, but he erases the time by vibrating the sandbox, something that took much experimentation to get right.

To do the actual vibrating he used a Seeed Studio vibration motor which has a permanent magnet coreless DC motor. Interestingly he first tried with a rectangular sandbox but that resulted in hills and valleys, so he switched to a round one instead. Different frequencies shifted the sand around in different ways, some moving it to the sides and even out of the sandbox, but trial and error uncovered the right frequency, duration, and granular medium. He experimented with different sands, including litter for small animals, and found that a powder sand with small, round grains works best.

Four white LEDs not only add to the nice ambience but make the writing more visible by creating shadows. The shells also cleverly serve double duty, both for appearance and for hiding things. Shells cause the arms to be practically invisible until they move (well worth viewing the video below), but the power switch and two hooks for lifting the clock out of the box are also covered by shells. And best of all, the tip that writes in the sand is a shell. There’s plenty more to admire about the cleverness and workmanship of this one.

We also have to wonder at what other dioramas are possible with this setup. How about a Halloween setting with a skeleton emerging from the sand? Perhaps white sand would make good snow for a Christmas setting?

Here’s the sandclock at an earlier testing stage but where you can better see the workings in action.

[via Adafruit]


Filed under: clock hacks

Decimal Time Clocks in under 1 kB

Humans historically have worked well with decimal numbering systems. This is probably due to the fact most of us have ten fingers, which make counting in base ten easy. Yet humanity seems to doggedly stick to the odd duodecimal/sexagesimal time system. [Danjovic] is bringing a bit of sanity into the mix with a decimal clock he calls DC-10. He’s entered his clock into our 1 kB Challenge.

DC-10 builds upon C10, the decimal time display system created by [KnivD] on Hackaday.io.

In [KnivDHere how it works:

  • 1 year = 365.25 days (we can’t change this anyway)
  • 1 day = 100 intervals (the equivalent of ‘hours’)
  • 1 interval = 100 centivals (equivalent of ‘minutes’)
  • 1 centival = 100 ticks (equivalent of ‘seconds’)
  • 1 tick = 0.0864 current seconds.

1kb-thumb[Danjovic’s] implantation displays intervals and centivals, exactly what you would need to know the current time of day. He used a Microchip PIC16F628 running from a 4 MHz clock. time is displayed on seven segment LEDs. The PIC is programmed in C, using the classic version of Microchip’s own IDE: MPLAB 8.92. The code uses 297 program words. Since the ‘628 uses 14-bit instructions, that equates to just under 520 bytes. Perfect for the 1 kB challenge!

If you have a cool project in mind, there is still plenty of time to enter the 1 kB Challenge! Deadline is January 5, so check it out and fire up your assemblers!


Filed under: clock hacks

7 Segment Display Using Neopixel Rings

There’s something about clocks — sooner or later, every hacker wants to build one. And we end up seeing all kinds of display techniques being used to show time. For the simplest of builds, 7-segment display modules usually get dug up from the parts bin. If you have a bunch of “smart” LED’s (WS2812’s, APA102’s), then building your own custom 7-segment modules isn’t too difficult either. [rhoalt] had neither, but he did have several 8 LED Neopixel rings lying around. So he thought of experimenting with those, and built a ‘Binoctular’ LED clock which uses the Neopixel rings as 7 segment displays.

figure-eight-segment-displaysEach digit is made using one pair of Neopixel rings, stacked to form a figure of eight. All the digits are composed of arcs, so readability isn’t the best but it’s not hard either. [rhoalt] does mention that the display is easier to read via blurred camera images rather than visually, which isn’t surprising. We’re long used to seeing numbers composed of straight line segments, so arc segmented digits do look weird. But we wouldn’t have known this if [rhoalt] hadn’t shown us, right ? Maybe a thicker diffuser with separator baffles may improve the readability.

The rest of the build is pretty plain vanilla — an Arduino Nano clone, a DS3231 RTC, a Lithium battery, and some buttons, all housed together in a laser cut enclosure which follows the figure of eight design brief. And as usual, once you’ve built one, it’s time to improve and make a better version.


Filed under: clock hacks, led hacks

A Different Sort of Word Clock

Our wonderfully creative community has a penchant for clocks. We have seen so many timepieces over the years that one might suppose that there would be nothing new, no instrument of horology that would not elicit a yawn as we are presented with something we’ve seen many times before.

Every once in a while though along comes a project that is different. A clock that takes the basic idea of a timepiece and manages to present something new, proving that this particular well of projects has not yet quite run dry.

Such a project is the circular word clock made by [Roald Hendriks]. Take a conventional circular wall clock and remove the hands and mechanism, then place LEDs behind the numbers. Add the words for “Quarter”, “Half”, etc. in an inner ring, and place LEDs behind them. Hook all these LEDs up to a microcontroller with a real-time clock, and away you go with a refreshingly novel timepiece.

[Roald]’s clock has the wording in Dutch, and the brain behind it is an Arduino Uno with the relevant driver ICs. He’s provided a video which we’ve put below the break, showing the clock in operation with its various demo modes.

We’ve seen so many word clocks over the years it’s best to give you a stream of them through our word clock tag. It’s good of this one to come along and refresh the genre.


Filed under: clock hacks

Exquisitely Crafted Nixie Tube Weatherclock

The Weatherclock is more than just a clock sporting Nixie tubes and neon lamps. There is even more to it than the wonderful workmanship and the big, beautiful pictures in the build log. [Bradley]’s Weatherclock is not only internet-connected, it automatically looks up local weather and sets the backlights of the numbers to reflect current weather conditions. For example, green for roughly room temperature, blue for cold, red for warm, flashing blue for rain, flashing white for lightning, scrolling white for fog and ice, and so on.

neonixieclock_02The enclosure is custom-made and the sockets for the tubes are seated in a laser-cut plastic frame. While seating the sockets, [Bradley] noticed that an Adafruit Neopixel RGB LED breakout board fit perfectly between the tube leads. By seating one Neopixel behind each Nixie indicator, each number could have a programmable backlight that just happened to look fabulous.

Witpreboxh an Electric Imp board used for WiFi the capabilities of the Weatherclock were rounded out on the inside. On the outside, a custom enclosure ties it all together. [Bradley] says his family had gotten so used to having the Weatherclock show them the outside conditions that they really missed it when it was down for maintenance or work – which shouldn’t happen much anymore as the project is pretty much complete.

It’s interesting to see new features in Nixie clocks. Nixie tubes have such enduring appeal that using them alone has its own charm, and at least one dedicated craftsman actually makes new ones from scratch.


Filed under: clock hacks