Master Clock Keeps Time for All Other Clocks

accurate clock

[Brett] just finished construction and long-term testing of this extremely accurate timepiece. It keeps such great time by periodically syncing with the atomic clock in Mainflingen, Germany.

The core of the project is an ATMega328 which uses the new DCF77 library for decoding the signal broadcast by an atomic clock. The libraries written by Udo Klein significantly increase the noise tolerance of the device reading the signal, but they will not work with any project that use a resonator rather than a crystal.

In the event of a complete signal loss from the atomic clock, the micro driving the clock also has a backup crystal that can keep the clock running to an accuracy of within 1 second per day. The clock can drive slave clocks as well, using pulses with various timings depending on what [Brett] needs them to do. The display is no slouch either: six seven-segment displays show the time and an LCD panel reads out data about the clock. It even has chimes for the hour and quarter hour, and is full of many other features to boot!

One of the most annoying things about timekeeping is daylight savings time corrections, and this clock handles that with a manual switch. This can truly take care of all of your timekeeping needs!

Gutenberg Clock Keeps Time by Reading Books

Gutenberg clock displaying text from a book

We’ve seen a wide variety of hacks that keep time, but [ch00f]‘s latest build takes a new spin on counting the seconds. The Gutenberg Clock keeps time by reading books on a scrolling LED screen.

The content for the clock is sourced from the Project Gutenberg, which releases books with expired copyright for free. The library on the clock consists of around twenty thousand such books. Read at eighty words per minute, the clock won’t repeat a passage for the next thirty-three years.

While the clock doesn’t display time itself, it is synchronized to time. Two identical clocks should display the same text at the same time. To get the time, [ch00f] first tried hacking apart a cheap radio clock, which is synchronized to NIST’s 60 kHz broadcast. After reverse engineering the protocol with great success, stray RF energy from the display turned out to cause too much interference.

With the cheap solution out the window, [ch00f] built a custom breakout for an Adafruit GPS module and used it to get the time. This was his first RF board, but it worked out fine.

Books are loaded onto a FAT filesystem on an SD card, and [ChaN]‘s FatFS is used to interpret the filesystem. A microcontroller then sends the text out at a constant rate to a serial port on the display which he hacked his way into.

The project is a neat mix of art and electronics. Stick around for a video overview after the break.

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Infinity Mirror Clock: There’s a Time Joke There Somewhere

Infinity Mirror Clock

We don’t think we’ve seen an Infinity Mirror Clock before, but we love this new twist on an old favorite. Different colors distinguish between seconds, minutes and hours, and an additional IR sensor detects when someone is directly in front of the clock and switches the LEDs off, allowing it to be used as a normal mirror. This build is the work of [Dushyant Ahuja], who is no stranger to hacking together clocks out of LEDs. You can tell how much progress he’s made with the mirror clock by taking a glance at his first project, which is an impressive creation held together by jumbles of wire and some glue.

[Dushyant] has stepped up his game for his new clock, attaching an LED strip along the inside of a circular frame to fashion the infinity mirror effect. The lights receive a signal from an attached homemade Arduino board, which is also connected to a real-time clock (RTC) module to keep time and to a Bluetooth module, which allows [Dushyant] to program the clock wirelessly rather than having to drag out some cords if the clock ever needs an adjustment.

Stick around after the jump for a quick demonstration video. The lights are dazzling to watch; [Dushyant] inserted a stainless steel plate at the center of the circle to reflect the outer rim of LEDs. After a quick rainbow effect, it looks like the mirror enters clock mode. See if you can figure out what time it is. For a more step-by-step overview of this project, swing by his Instructables page.

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POV Display Does it on the Cheap


[Sholto] hacked together this ultra low-budget spinning display. He calls it a zoetrope, but we think it’s actually an LED based Persistence Of Vision (POV) affair. We’ve seen plenty of POV devices in the past, but this one proves that a hack doesn’t have to be expensive or pretty to work!

The major parts of the POV display were things that [Sholto] had lying around. A couple of candy tins, a simple brushed hobby motor, an Arduino Pro Mini, 7 green LEDs, and an old hall effect sensor were all that were required. Fancy displays might use commercial slip rings to transfer power, but [Sholto] made it work on the cheap!

The two tins provide a base for the display and the negative supply for the Arduino. The tins are soldered together and insulated from the motor, which is hot glued into the lower tin. A paper clip contacts the inside of the lid, making the entire assembly a slip ring for the negative side of the Arduino’s power supply. Some copper braid rubbing on the motor’s metal case forms the positive side.

[Sholto] chose his resistors to slightly overdrive his green LEDs. This makes the display appear brighter in POV use. During normal operation, the LEDs won’t be driven long enough to cause damage. If the software locks up with LEDs on though, all bets are off!

[Sholto] includes software for a pretty darn cool looking “saw wave” demo, and a simple numeric display. With a bit more work this could make a pretty cool POV clock, at least for as long as the motor brushes hold up!

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Cold War Clock is all Tubes

A clock built from tubes


Clocks are great projects to build. They serve a real purpose, and there’s a wide variety of ways to implement a unique timepiece. [Hank]‘s Cold War Clock only uses parts and technologies that were available in 1959. It contains no semiconductors, but has an audible alarm and reasonable time accuracy.

Looking through the hand drafted schematics, you’ll find a number of Dekatron tubes. These vintage components are used as registers to store and count the time. [Hank] found some cheap Soviet Dekatrons, but had to machine his own sockets to connect them. These tubes do the counting, but the actual display consists of nixies.

A cost estimate puts this clock at $2130 in 1959, which equates to $17040 today. Clearly this would be outside the price range of most hobbyists. The actual build cost [Hank] around $1600.

There’s some intricate details in this build. The front panel has an authentic look to it, and the manual has instructions for “demolition of clock to prevent enemy use.” [Hank] calls it a “creative anachronism.” In a sense, it’s a reproduction of a product that never actually existed.

A video of this clock in action, including the Cold War era alarm, is after the break.

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A Laser Cut Word Clock

DIY laser cut word clock.

What is a word clock? A word clock is a clock that displays the time typographically that is also an interactive piece of art. Rather than buy one for $1500, [Buckeyeguy89] decided to build one as a present for his older brother. A very nice present indeed!

There are many different things that come into play when designing a word clock. The front panel is made from a laser cut piece of birch using the service from Ponoko. Additionally, white translucent pieces of acrylic were needed to keep each word’s light from bleeding into the neighboring letters. The hardware uses two Arduinos to control the LEDs and a DS3231 RTC for keeping accurate time. The results are very impressive, but it would sure make assembly easier if a custom PCB was used in the final version. For a one-off project, this makes a great birthday present.

The craftsmanship of this word clock is great, making it well suited for any home. What projects have you built that involve more than just electronics? Sometimes, quality aesthetics make all the difference.

Go Vintage! Learn to Repair and Restore Mechanical Pocket and Wrist Watches.

pw tear down 1

Until recently, watches have been entirely mechanical where each wheel, gear, and mechanism representing a milestone in our understanding of precision manufacturing and timekeeping.

One of the very first watches, created by a locksmith.

One of the very first watches, created by a locksmith.

Today it is nearly impossible to find watchmakers to service or repair vintage mechanical pocket and wristwatches, so we have to do it ourselves. Learn to repair vintage mechanical watches. You can do this and we’ll show you how.

They tick, mechanical watches have a pulse. First created in the 16th century by locksmiths, these early watches could only resolve time down to the hour and for this reason displayed time with only one hour hand.

By the 18th century fusee technology enabled watches to achieve accuracies to within seconds.

[Read more...]


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