Time inverting hourglass

Category: Inventions
Collaborators: Meta Grgurevič

Time inverting hourglass cover picture

Another project together with Meta and a group of other people. As always with her, the aim was to find something very simple and basic about the laws of nature, and twist it into something impossible. This time, we chose time. As suggested to me by an unnamed person (or maybe I know him? I just completely forgot who told me this), to invert time you just have to get the sand in a hourglass run upwards. I happened to mention this idea to Meta when she was despairing over what to make for the 31st Ljubljana graphic biennale. She liked the idea, and now such an hourglass exists.

The name of the artwork in the biennale, centered around the hourglass, was Meriliniki časa / Timekeepers.

This was a group piece with multiple people working on it. In addition to electronic parts by me, also involved were a metalworker, a glassblower, a company making concave mirrors, and a company casting items from brass. The message is that a group of people with diverse skills can achieve the impossible.

Unfortunately, I did not have so much to do with the inversion of time itself, as this was achieved by Meta’s ingenious idea of using shaped mirrors. Then the sand seems to run upwards, inverting time. As there is only so much sand in a hourglass, and the show lasts for months, we created an automatic mechanism for turning it around. A metallic arm holds the hourglass, and a motor turns the arm.

My part of the whole is the control unit. We measured that it takes almost 16 minutes for the sand in the hourglass to run. So a microcontroller activates the motor every about 16 minutes, and keeps it running until the rotating arm hits a button which is positioned to signal 180° rotation. This system was originally done because it was not realistic to demand the gallery staff to turn the hourglass all the time. However, the automated effect produces a very beautiful effect when the motor slowly and precisely turns the hourglass.

Some recycling was involved in this project. I put the control unit into box of an old dvd player. I could use the ac-dc converter inside directly for feeding the microcontroller. Unfortunately, attempts at reusing the lcd screen for something failed.