CD-ROM POV Clock

September 28, 2013 by James Hobson 12 Comments

[Kyle] wanted to try something new. A Persistence of Vision Clock using a CD-ROM drive.

We have covered lots of POV Clocks that make use of hard drives, but we think this is the first time we have seen a CD-ROM drive used instead. [Kyle] points out that CD-ROM drives are typically much quieter than hard drives, which is the main reason he chose the CD-ROM route.

At the heart of this project is a good old ATMEGA168 and an RGB LED strip for the lights. To measure and maintain the rotational speed of the clock [Kyle] used an IR photodiode that detects a reference mark on the disc. An elegant build of a classic POV Clock, with a new twist!

The cool thing about this project is he did not actually use the CD-ROM drive like you think he would — he chucked the spindle motor and instead is spinning the disk using the tray ejection motor! He did this so he could control the motor by PWM straight off the microcontroller, whereas the spindle motor would require an IC and a varying control signal with specific voltage amplitudes.

He also experimented with different backgrounds and background lighting, which you can see in the video after the break!

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A Simple Nixie Clock With Logic Gates

September 27, 2013 by Mathieu Stephan 11 Comments

Here is a very nice project that [Znaxque] finished a few months ago: a simple nixie clock made with logic gates only. In this build, the mains 50Hz is used as a time base instead of a 32KHz crystal that most readers here may use. In the very long term, this clock may actually be more precise than a crystal-based one as power companies in Europe adjust the mains frequency. However, at a given moment the difference between this clock and a reference may be as big as 60 seconds.

The design was sketched on a simple piece of paper and later made using salvaged ICs. [Znaxque] only bought the six IN-14 nixies for $45 and the veroboard shown in the picture above. The BCD to Decimal decoders are 74141s and three buttons are present on the board to set minutes, hours, as well as resetting all the counters.

How Much Can You Cram Into A Wristwatch

September 27, 2013 by Brian Benchoff 45 Comments

Creating wearable electronics that are functional and not overly bulky is very, very hard. [Zak], though, makes it look easy. He started his DIY digital wrist watch to see how much he could cram into a watch-sized device. The finished product is really incredible, and one of the most amazing DIY watches we’ve ever seen.

The electronics for the watch include an ATMega328p, a DS3231M Real Time Clock, a Microchip battery charger, and a few resistors and caps. The display is an OLED, 1.3″ wide and only 1.5 mm thick, contributing to the crazy 10mm overall thickness of the watch.

The software is where this watch really shines. Along with the standard time and date functions, [Zak] included everything and more a wrist watch should have. There is an interface to set up to ten alarms on different days of the week, a Breakout and ‘Car Dodge’ game, a flashlight with integrated ‘rave’ mode, and a stopwatch. On top of this, [Zak] included some great animations very similar to the CRT-like animations found in Android.

It’s a fabulous piece of kit, and if any project were deserving of being made into an actual product, this is it.

You can check out [Zak]’s demo of all the functions of his watch below.

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Jeep Dashboard Display Turned Into A Desk Clock

September 9, 2013 by Mike Szczys 16 Comments

This display is easily recognizable by the buttons and the outline of a vehicle to the left. It’s a Vehicle Information Center (VIC) from a Jeep Grand Cherokee. [Florlayamp] discovered a row of the vehicles in a junkyard, all with the displays still intact. He grabbed one and turned the VIC into a desk clock. What would you pay for such a fine piece of used electronic hardware? How about six bucks? Yeah!

Getting it running couldn’t be simpler. It’s all set up to be programmed and run on it’s own. A bit of searching around turned up a schematic to figure out which wires are for power. It took some time to figure it out, but the thing draws about 2A so finding a worthy wall wart was a must.

Now that he was sure it would work [Florlayamp] started on the case build. It’s poplar with quarter round to frame the display. On the back you’ll find a single rocker switch.

Usually we see the opposite of this, adding displays to the dashboard instead of salvaging them.

A Weekend Trip To Verify General Relativity

September 3, 2013 by Mathieu Stephan 77 Comments

8 years ago, for the 100th anniversary of the theory of relativity [Tom] decided to test the general theory of relativity.

As he was going to Mt Rainier (5400ft high) with his children for the weekend, he brought in his van 3 cesium clocks while leaving other atomic clocks at his home for comparison. The theory behind the test is that if you’re are at higher altitudes, then your speed (in a galactic coordinate system) is higher than the one you’d have at sea level and therefore time would go “slower” than at lower altitudes.

[Tom] brought 400 pounds of batteries, 200 pounds of clocks and left his car turned on during his 2 days stay in the ‘Paradise Lodge’. He used 120V DC to AC converters and chose to bring 3 cesium clocks to have a triple redundant setup. When he came back home, he had the good surprise of finding a time difference of 23ns. This is a great application for those rubidium sources you’ve been scavenging.

[Thanks Indyaner via Reddit]

Unreadable Binary Epoch Clock Is Unreadable

August 14, 2013 by Mike Szczys 38 Comments

What time is it? For that matter, what is the date? This clock can tell you both of those things, if only you could read it. The inspiration for this Binary Epoch kit came after a friend of [Maniaclal Labs] built an eight-bit binary clock. That’s a pretty common project that gets riffed on for things like mains-timed logic-driven clocks. They figured why not make it bigger? But even then you can make some sense out of the display after studying it for just a bit, you won’t be much closer to answering those two questions.

The problem is that this is unreadable in a couple of different ways. First off, how long did it take you to figure out in your head the decimal equivalent of the binary number displayed above? We gave up. But pounding the number into Google (search for: 0b01010010000010000001001010010011 in decimal) gives us 1376260755. meaningful? Again, not to a human. This is Unix time, which is the number of seconds elapsed since the Epoch: 8/11/13-22:39:15.

Check out the video below that shows how to set the clock, which uses a menu system for human-friendly input. But since it’s Arduino compatible you can also connect an FTDI cable and program it from a computer. Oh, and since this is Open Source Hardware (note the icon in the lower right) you can get all the info to build (or breadboard) your own from their Github repo.

Here’s another complicated clock that uses Nixie tubes to display time and date info which is actually of use.

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An Elegant Timepiece From Paper And A Fistful Of Servos

August 12, 2013 by Marsh 14 Comments

Segments rise from a sheer white surface to reveal the time in this papercraft digital / analog clock build by [Jacky Mok].

New York-based designer [Alvin Aronson] is responsible for the original, titled “D/A Clock,” which he built as a student at RISD using Corian instead of paper. [Aronson]’s design is also massive in comparison. It measures one meter wide by a half meter tall. Without access to either a 3D printer or to a laser cutter, [Jacky] instead reduces the scale of his interpretation and relies on cardstock as the primary construction material. His experience with papercraft typography leads to a design that anyone with an Exacto knife and a slice of patience should find manageable. [Jacky] ignores the Exacto option, however, and cuts his pieces with a tool we saw earlier this year: the Silhouette Portrait.

The clock’s electronics include an Arduino Uno, a servo motor controller, twenty-eight servos and an RTC breakout board that handles timekeeping. Each servo drives its own segment by sliding a paperclip forward or backward inside a small, hollow aluminum rod. Though we’re still holding out for a video of the finished papercraft build, you can watch a video of Aronson’s original clock after the break and see what inspired [Jacky’s] design.

Need another clock to envy? Last month’s build by [ebrithil] uses twenty-two servos to individually spin the segments. If you prefer that your clocks light up, [Aaron’s] o-scope transformation has you covered.

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