Volt Meter Clock Also Displays The Temperature

August 24, 2012 by Brian Benchoff 10 Comments

[IronJungle] got around to putting together every tinkerers favorite project: a clock with a strange way of displaying the time. For his clock, [Jungle] took a trio of voltmeters and turned them into a clock that displays the current hour, minute, and second on custom paper dials.

[IronJungle] connected a PIC 14M2 microcontroller to a DS1307 real time clock to keep track of the current time. As for display, [Jungle] took a trio of volt meters and wired them in to the PWM outputs on his PIC. With this, he was able to precisely control the position of the needle in the meter, and thus display the time.

In addition to displaying the time, [IronJungle] added a small temperature sensor to his build. By pressing a button below the seconds display, the clock is able to display the current temperature in Fahrenheit, Celsius, and Kelvin.

After the break you can check out a time-lapse video of [IronJungle]’s voltmeter clock going through the hours.

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Network Time Clock For A Home Media Center

August 22, 2012 by Brian Benchoff 22 Comments

[Derek] wanted a clock for his media center. A simple wish, but he had a few requirements: he didn’t need an alarm, wanted it to automatically set its time after a power outage, needed a big display, and also wanted it to look good. After shopping around [Derek] couldn’t find a clock that would fit his requirements so he decided to build one.

[Derek]’s project is called the SNTP clock. As you might expect, it gets its name from the protocol used to automatically synchronize the clock in your computer with other network time servers. The clock itself is built around an ATMega168 gathering time data from the Internet with the help of a Lantronics XPort. One inch seven segment LEDs serve as the display for the clock, and everything, from the time offset from UTC, the brightness of the display, and whether the clock displays 12 or 24-hour time is controlled by an infrared Apple remote.

A bare PCB or bundle of wires would look out of place in [Derek]’s media shelf, so he used a metal picture frame and smoked acrylic to dress up his clock. Now he’s got a beautiful and elegant clock that fits right in to his media servers and receiver.

CMOS Logic Clock Tracks 24-hour Time

August 20, 2012 by Mike Szczys 18 Comments

Here’s an IC logic project that displays 24-hour time. Planning was the name of the game for this project. [Mattosx] took the time to layout his design as a PCB in order to avoid the wiring nightmare when build with point-to-point connections.

Much of the complexity is caused by the display itself. Each of the six digits has its own binary-coded decimal chip and array of discrete resistors. Timekeeping is handled by six decade counters, two divider chips, one AND gate chip, and one OR gate chip. He chose a SOIC crystal oscillator chip as the clock signal. We’re more partial to the idea of using mains voltage as the clock signal.

[Mattosx] posted the board artwork if you’d like to etch your own 5″x8″ PCB. Just make sure you read through all of his notes as not all of the chips are oriented in the same direction.

[via Reddit]

Connect 4 Binary Clock

August 15, 2012 by Mike Szczys 5 Comments

As part of a class at University, [Emacheen22] and his teammates turned an old Connect 4 game into a binary clock. This image shows the device nearing completion, but the final build includes the game tokens which diffuse the LED light. We enjoy the concept, but think there are a few ways to improve on it for the next iteration. If you’re interested in making your own we’d bet you can find Connect 4 at the thrift store.

Instead of using the free-standing game frame the team decided to use the box to host the LEDs and hide away the electronics. Since they’re using a breadboard and an Arduino this is a pretty good option. But it means that the game frame needs to be on its side as the tokens won’t stay in place without the plastic base attached. They used a panel mount bracket for each LED and chose super glue to hold all of the parts together.

We think this would be a lot of fun if the frame was upright. The LEDs could be free-floating by hot glueing the leads to either side of the opening. Using a small box under the base, all of the electronics can be hidden from view. After all, if you solder directly and use just a bare AVR chip there won’t be all that much to hide. Or you could get fancy and go with logic chips instead of a uC.

Atomic Clapperboard

August 2, 2012 by Mike Szczys 13 Comments

Whether you know it as a clapperboard, a slate, slate board, time slate, or by another name, you probably recognize this staple of movie making. It’s a handy way to help synchronize sound with video, and to keep track of clips when it comes time to edit. But this clapperboard is quite a bit more accurate than most. It’s got an atomic clock source for dead-on accuracy.

The project came from the growing availability of Rubidium clock source modules on eBay. They can be had for under $100 and you’ll enjoy accuracy of 0.1 ppm. [Luddite Tech] grabbed one for himself and included it in this build. As you can see in the clip after the break, the contrast of the eight-digit display is adjustable, and shines brightest when the marker is snapped. We’d guess the cable he connects at the beginning of the demo is used to set the initial time reference. After that the in-built WiFi can be used to push the time markers to a computer.

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Magic Clock Locates Your Friends

July 30, 2012 by Brian Benchoff 15 Comments

Just like the clock from Harry Potter, a team of media informatics students at the University of Munich built a grandfather clock that doesn’t keep track of time; instead, it keeps track of where everyone is, whether it be their university, work, or in prison.

The build uses Android and iOS apps on each team member’s cell phone to send their current location to a web server. A circuit built inside an old grandfather clock the team picked up from eBay communicates with the web server through a WiFly Shield to control a quartet of servos and drive the clock hands.

Because the grandfather clock only came with two clock hands, the team used a series of four concentric shafts to move each hand around the dial. With a bit of clever gear fabrication on their laser cutter, they were able to use unmodified servos move the hands all the way around the clock.

The avatars on the tip of each clock hand are the remains of decapitated LEGO minifigs, a choice that makes sense after viewing the build video available after the break.

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How’s The 60Hz Coming From Your Wall?

July 24, 2012 by Brian Benchoff 51 Comments

If you’ve ever wondered why NTSC video is 30 frames and 60 fields a second, it’s because the earliest televisions didn’t have fancy crystal oscillators. The refresh rate of these TVs was controlled by the frequency of the power coming out of the wall. This is the same reason the PAL video standard exists for countries with 50Hz mains power, and considering how inexpensive this method of controlling circuits was the trend continued and was used in clocks as late as the 1980s. [Ch00f] wondered how accurate this 60Hz AC was, so he designed a little test.

Earlier this summer, [Ch00f] bought a 194 discrete transistor clock kit and did an amazing job tearing apart the circuit figuring out how the clock keeps time. Needing a way to graph the frequency of his mains power, [Ch00f] took a small transformer and an LM311 comparator. to out put a 60Hz signal a microcontroller can read.

This circuit was attached to a breadboard containing two microcontrollers, one to keep time with a crystal oscillator, the other to send frequency data over a serial connection to a computer. After a day of collecting data, [Ch00f] had an awesome graph (seen above) documenting how fast or slow the mains frequency was over the course of 24 hours.

The results show the 60Hz coming out of your wall isn’t extremely accurate; if you’re using mains power to calibrate a clock it may lose or gain a few seconds every day. This has to do with the load the power companies see explaining why changes in frequency are much more rapid during the day when load is high.

In the end, all these changes in the frequency of your wall power cancel out. The power companies do the same thing [Ch00f] did and make sure mains power is 60Hz over the long-term, allowing mains-controlled clocks to keep accurate time.