Rolling Digit Clock Is A Wonderful Piece Of Engineering

March 1, 2012 by Brian Benchoff 16 Comments

A long time ago and on a scrounging trip he barely remembers, [Victor] bought a quartet of digits from an old Dutch Railways clock. These antique displays used a strip of plastic coated cloth that rolls around itself with the help of a motor to display the digits 0 through 9. It’s been many years, but [Victor] finally got around to building a clock out of these single digit displays and we’re loving the results.

Because these displays were manufactured in a time when mechanical devices were king, [Victor] had to slightly modify each digit so they could display numbers with the help of a continuous rotation servo. The four servos are controlled by an Arduino – each digit changing one at a time to reduce current consumption – and a magnet and reed switch was added to each digit so the numbers could be repeatedly displayed.

Before [Victor] replaced the plastic servo gears with metal cogs, the clock was quite noisy. He’s since put each digit underneath a bell jar (actually a vase turned upside down), and we’ve got to say that [Victor] has a nice clock on his hands. Check out the videos of the clock changing digits to display the time after the break.

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Checking The Accuracy Of Fake Watches

February 23, 2012 by Brian Benchoff 82 Comments

Since [th3badwolf] realized a wrist watch is the ultimate men’s fashion accessory, he’s been trolling around eBay looking for a nice looking, but still inexpensive wearable chronometer. The Fauxlex brand isn’t normally regarded for accurate time keeping, so he decided measure the accuracy of his off-brand watches in a really clever way.

[th3badwolf] had a camera with a built-in intervalometer lying around and figured if the camera was set to take one picture a minute, the second hand would stay still while the minute and hour hands moved. An hour-long test confirmed his theory and he pointed his cameras towards his knock-off watches.

In the resulting time-lapse video available after the break, [th3badwolf] calculated that the first and third watches lose about 24 seconds a day. He attributes this fact to the watches having the same clockworks. The second watch gains nearly three minutes a day, and he’s trying to send that one back to the supplier. We’re not sure how that will end up, but at least [th3badwolf] has two reasonably accurate watches now.

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Hacking An AC Outlet Timer For Project Use

February 17, 2012 by Mike Szczys 3 Comments

[Karl] needed a programmable real-time clock for one of his projects. He considered adding an RTC chip, LCD screen, and some buttons for use with a microcontroller. That’s not necessarily hard, but it takes time and can be considered a project in itself. Instead, he headed to the hardware store to look for a cheap solution. He was able to get this AC outlet timer for a song. It’s got everything he needs; twenty programmable on/off events, a calendar to track time and day of week, and a user interface made up of a low-power LCD and four buttons. He cracked open the case and patched into the electronics for use with any project.

You can see the solder-tab battery in the middle of the board (green coin-cell). That actually runs the timer circuitry and display. It’s topped off when the unit is plugged into mains, but [Karl] ended up replacing it with a much higher capacity AA rechargeable battery. The device works just like a thermostat, using very little power and driving a relay at the appropriate time. Batteries in thermostats seem to last forever and we can expect the same performance from this device. [Karl] rerouted the trigger signal from the relay to his own 2N2222 transistor. This way the device can switch loads running at voltages other than its own 1.2V operating level.

Stock timers are great. They’re mass-produced which makes them cheap, and you can do some interesting stuff with them. We really enjoyed see this other mechanical version hacked for hydroponic use.

POV Clock Spins Light Filter Instead Of LEDs

February 10, 2012 by Mike Szczys 21 Comments

This hard-drive based POV clock is a treasure trove of great design choices. Now, we’ve seen a bunch of spinning clock builds. Several of the hard drive versions use slits cut in the platters to create a display by illuminating an LED behind those slits at just the right moment. This is a similar idea but [Jason Hotchkiss] ditched the platters all together and replaced them with a light filter. The filter disc has digits 0-9 as well as a colon (not seen above because the colons blink each second). As this disc spins, the Arduino compatible controller lights up LEDs in the eight digital positions to illuminate the correct number.

The filter is made from an etched copper-clad disc. This is a great choice because the fiberglass substrate is strong, light weight, translucent, and available. The filter idea also means you don’t need to get power or data to a spinning platform. [Jason] has also designed a very impressive controller board that is the same size as the footprint of the laptop hard drive he’s using. Check out the video after the break to see his description of what went into the hardware choices he arrived upon. Continue reading “POV Clock Spins Light Filter Instead Of LEDs” →

Very Accurate Clock Can’t Be Read Accurately

January 25, 2012 by Mike Szczys 10 Comments

[Martijn] is showing off his new clock which he calls a Light Spectrum Clock. We like to look of it, using RGB LEDs in five squares that remind us of some of those LED coffee table builds. From left to right this shows the week, day, hour, minute, and second. Simple, right?

We had to smile a little bit when looking through his write up. He chose an Arduino nano as a controller, using a TLC5940 chip to drive the LEDs. But it is the inclusion of a DS1307 real-time clock that we find amusing. It will keep quite accurate time (not quite as well as the DS3232 but still respectable) but the fuzzy display technique makes telling the time accurately an impossibility. But like other color-based clocks, that’s part of the fun. The real reason for using an RTC chip is that they usually include battery-backed operation so that you can shut off the LEDs when you’re not around and the clock will continue to tick.

You can watch the seconds pass by as fading colors in the clip after the break.

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Tutorial: Build A Manifold Clock For $10

January 25, 2012 by Brian Benchoff 35 Comments

Every once in a while, the Hack a Day tip line gets a submission that is cool, but screams to be built in a few hours, possibly while consuming adult beverages. When [Shay] and [Ben] sent in their Manifold Clock Kickstarter, I knew what I had to do. To make a long story short, there’s a manifold clock hanging on my wall right now. Check out my manifold clock how-to guide after the break.

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Trashed Hard Drive? Why Not An Engraved Clock?

January 21, 2012 by Jeremy Cook 19 Comments

So your hard drive quit working. Don’t despair, with a “little” work your disk can be repurposed into a clock like the one seen above. I made this clock after several iterations of various success, including the first revision, which was simply the platter with a clock kit from a hobby store screwed into the middle. Still a very neat effect, but if you want to actually tell what time it is, it helps to have the numbers available.

For this, you’ll need some sort of CNC machine (a kit-build router in this case), and some way to generate the Gcode to get everything cut correctly. A guide to how the logo was eventually turned into something a machine could understand is provided here. Of course if you’re not sure what logo would look good on your clock, you can always skip a few steps and engrave the our logo. In this [HAD] article, it’s conveniently provided in .dxf format, which can be converted by a CAM (computer-aided manufacturing) program into code that your machine can understand.

Check out after the break for a video of two “platter clocks” being engraved using these methods: Continue reading “Trashed Hard Drive? Why Not An Engraved Clock?” →