Domino Clock Uses An Electromechanical Display

December 18, 2010 by Mike Szczys 19 Comments

This clock concept uses big dominos with changing faces to display the time. As far as we can tell they haven’t made it through to a finished product yet, but we loved the explaination of the engineering that went into the prototype. After the break you can watch [Eric] explain how he accomplished the design requirements of a slowly changing digit that uses no power to keep its state, which also uses low-power when changing state. To accomplish this he designed a flipping circle that stays put in both the white and black positions once set. When it’s time to change the digits, a coil is energized to push against a magnet in what he calls a single poled motor. Whatever the name, we want to build one ourselves!

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Ice Tube Clock, Meet The ChronoDot

December 9, 2010 by Mike Szczys 5 Comments

[Alex] ramped up the precision of his timepiece by adding a ChronoDot to the Ice Tube Clock. These two items are among our favorites; the Ice Tube Clock for its old-style multi-digit display, and the ChronoDot for combining a DS3231, battery, and components into a nice small package.

There is a schematic link at the very bottom left of [Alex’s] writeup. He mentions that he depopulated the clock crystal and its capacitor pair from the board and patched into the clock input on the AVR. A 100K pull-up resistor is included in the wiring as called for in the DS3231 datasheet. Although not specifically referenced, we assume that [Alex] reprogrammed the ATmega168 clock select fuses to use an external clock signal.

Now he can sit back knowing that the clock will be within 10 seconds per year accuracy.

Meter Clock With Pleasing Design Considerations

December 6, 2010 by Mike Szczys 14 Comments

[AndyO] embraced his inner geek by building this meter clock. It exhibits a lot of features that you’d want to see in a home-built timepiece, include over-complexity, abundant features, and RGB LEDs. We’re fascinated by the design he put into this. For instance, the two indicator LEDs on the clock face are not poking through the surface, but use brass tubes as light pipes. Also, the three buttons on the top are almost indistinguishable, and have an RGB back light that places a halo around each. The case itself was built by first making a form, then laminating thin sheets of wood (a difficult task due to the tight curves). The needles themselves are not actually meters, like the clock the inspired the build, but are attached to servo motors. This all comes together into a fascinating build, and a great writeup.

[Thanks Graham]

Hot Resistors Used For Color-changing Clock Face

December 5, 2010 by Mike Szczys 37 Comments

[Sprite_TM] built a full clock display using thermochromic paint. This picks up where he left off with his paint-based 7-segment display prototype. He never really saw that design through to a finished project, but he recently came across the leftover paint and decided to do something with it. Instead of making thin traces on a PCB he’s heating up resistors mounted on protoboard. Each resistor has been coated with the black/light grey paint after getting a rough sanding on the tops of the packages. Run around 500mW through a segment and they heat up enough to change the paint to light grey. Once shut off, the segments gradually fade over the next 60 seconds.

Warm Tube Clock

November 29, 2010 by Mike Szczys 19 Comments

The Warm Tube Clock is the new kid on the block of Nixie Tube clocks. It takes inspiration from, and uses the same voltage driver circuit as the Ice Tube Clock. But this one uses four tubes instead of that hard-to-find single tube. It has a few other tricks up its sleeve. The shield that hosts the tubes has been designed for two different types. It also hosts an RGB LED for each tube, which adds the green glow seen above, and has a couple of small neon indicator bulbs which serve as the colon between hours and minutes.

The driver board centers around an ATmega328 running about three thousand lines of code. The firmware offers a lot of options including sound feedback, and a setting for every clock, calendar, alarm, and LED color toggle imaginable. See for yourself as the settings video, embedded after the break, walks you through each stage of the menu. We can’t help but think you need an instruction manual to set this thing up.

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Nixie Frequency Counter Gone Timepiece

November 12, 2010 by Mike Szczys 25 Comments

[Windell] of Evil Mad Scientist Laboratories took an ancient Nixie tube based frequency counter and converted it into a clock. The unit he got his hands on is an HP model that was still in great shape. He’s using an internally generated one second pulse as the clock signal, but some modifications are necessary to display time. That’s because the frequency counter is base 10 and clocks use a quirky combination of base 60 and base 12.

It wasn’t too much of a problem to rig up a system to track minutes and seconds. The tens digit for each is monitored by a couple of AND gates that he added to the mix. When they detect a ‘6’ the digit is reset and a pulse increments the next digit as the carry. This is more difficult to accomplish with the hours though. Minutes and seconds count from 0 to 59 but hours don’t start at 0. Instead of over-complicating the logic [Windell] used a bit of slight-of-hand. The Nixie tubes for the hours have been rewired so that when the counter is at 0, the filament in the shape of a 1 lights up. No difference in logic, just a translation that makes them display one digit higher than the actual count.

Master Clock System Uses All Logic, No Microcontrollers

October 17, 2010 by Mike Szczys 17 Comments

What you see above is a master clock. It is the center of a system that can run an unlimited number of slave clocks, keeping them on-time thanks to its ability to synchronize with an atomic clock. [Brett Oliver] put together the project back in 2005 using digital logic chips, and no programmable microcontrollers. This includes everything from the binary decoders that drive the 7-segment displays, to the radio transceiver board that gathers the atomic clock data, to the various dividers that output 1 second, 2 second, 30 second, 1 minute, 1 hour, and 24 hour signal pulses. It’s a well document and fascinating read if you’re interested in digital logic clocks.