This Hourglass Flips Itself

Once upon a time, [Mike] bought an hourglass for his sister. He intended to build it into a clock and give it to her as a gift, but life and other projects got in the way. Fast forward a couple of decades to the point when it all came together and [Mike] had everything he needed on hand to build a beautiful wooden clock that automatically flips the hourglass over.

Every 60 minutes, the bulb, which is situated inside a handcrafted maple ring, rotates 180 degrees to restart the flow of sand. Whatever number is at the top of the outer wheel denotes the current hour. The digit for the next hour is always at the five o’clock position relative to the current hour. This works out because the pockets on the outside of the bulb’s ring share a 5:6 ratio with the gear teeth on the outer ring. Confused? Watch the time-lapse video from [Mike]’s that shows it in action.

[Mike] was determined to build this clock using only things he already had on hand, like a cheap digital watch to keep time and a car window motor to rotate the hourglass. He hacked a USB port into the watch so he could use the hourly chime function to trigger the motor through a quad op-amp. The motor runs until it is triggered to shut off optically—a pair of slits cut into the gear that moves the hourglass pass over a sensor. [Mike] built a beautiful box to hold the guts from a nice piece of walnut and spared no detail in the design.

There are a ton of build pictures on the projects site and an in-depth video tour of the clock, which is embedded after the break. Whether they are designed to amaze or confuse, we love a good clock build around here. If you’re into hourglasses, we featured a digital version not too long ago.

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Texel: Art Tracks You, Tracks Time

French robot-artist [Lyes Hammadouche]  tipped us off to one of his latest works: a collaboration with [Ianis Lallemand] called Texel. A “texel” is apparently a time-pixel, and the piece consists of eight servo-controlled hourglasses that can tip themselves over in response to viewers walking in front of them. Besides making graceful wavelike patterns when people walk by, they also roughly record the amount of time that people have spent looking at the piece — the hourglasses sit straight up when nobody’s around, resulting in a discrete spatial representation of people’s attentions to the piece: texels.

We get jealous when we see artists playing around with toys like these. Texel uses LIDAR scanners, Kalman-filtered naturally, to track the viewers. openFrameworks, OpenCV, and ROS. In short, everything you’d need to build a complex, human-interactive piece like this using completely open-source tools from beginning to end. Respect!

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Wine glass time keeper

We’ve seen a glut of time-keeping projects lately. We guess time was the original motivator for technology so we’re okay with it (but we’re not calling ourselves Clockaday quite yet). This clock, or more appropriately this timer, is a homemade hourglass that [Andrei] put together. The finished look is simple but he put some real time into its production.

The glass portion is a combination of two wine glasses. He removed the stems, ground the bottoms flat, then drilled holes to allow the sand to pass. He used plumbers putty around the top of the upturned reservoir to create a temporary bowl of water which cooled the glass during drilling. This prevented cracking by keeping the friction generated heat at bay. Working with the glass took a total of around five hours.

To assemble, he epoxied the two wine glasses together, routed out a ring in the wood bases for the lips, and used dowels to connect the two ends. [Andrei] concluded that the gentle slope at the bottom of the wine glasses is not the ideal shape as some sand can get stuck in them. Perhaps champagne flutes for his next build? At any rate, we think it’s a unique, non-automated hourglass build.

A random USB… hourglass

[Peter] thought of a creative, way to generate random entropy for under $100.

The USB Hourglass combines a sand timer with a rotating mechanism and an optical beam through the center of the timer to observe the falling sand. The amount of light reaching a detector is digitized at frequent intervals and processed by a microcontroller to determine when to rotate the hourglass. The digitized light levels are also sent by USB to a host PC where they can be used as a source of random entropy. Power is supplied over the USB cable.

With the USB Hourglass, the user can look at the sand falling through the center of the hourglass and monitor the randomness in the USB output data. And one can read the code line-by-line, compile it, and upload it to the microcontroller using only open-source and widely supported tools.