Sant Pol, What Time Is It?

Solr Is Like a Digital Sundial for Your Wrist.

Jeremy S. Cook
Jul 28, 2017 · 2 min read

Xose Pérez — a resident of the small town of Sant Pol, north of Barcelona, Spain — rather than buying a normal watch, built the Solr digital wrist watch, a sort of a digital wrist-mounted sundial. The user reads this device by aligning the sun’s shadow from a nylon screw with a white line on the watch’s PCB face. When this is aligned correctly, direction is sensed by a magnetometer, which is then used to calculate the time, shown on a tiny numeric indicator below the dial.

The watch is equipped with an ATmega328P and a four-digit QDSP-6064 bubble display. (📷: Xose Pérez)

Solr is somewhat inaccurate due to the variation in the sun’s transit through the sky, as well as any user error; yet, he justifies the watch design as a possible excuse for being late, or simply as a way to embarrass your kids! However the watch is justified, it’s a unique project that reads time in a very fascinating way. If better accuracy was needed, the month and day could be added in to compensate for the sun’s variation throughout the year.

A closer look at the PCB watch face. (📷: Xose Pérez)

Interestingly, according to Pérez’s write-up, there is a legend in the town of Sant Pol that says that people there restored an old sun dial that had been tarnished by the sun and rain, placing it under a roof in order to keep it pristine. This, of course, prevented the sundial from working correctly, and those from neighboring towns would mockingly say to them “Sant pol quin’hora és?” or “Sant Pol, what time is it?” This irony isn’t lost on Pérez, who points out that this could be classified as a useless project, especially since the the tiny numeric display is difficult to read in the sun!

Hackster Blog

Hackster.io, an Avnet community, is the world’s largest network for hardware & software developers. With 1 million members and 17,000+ projects, beginners and professionals can learn and share how to build robotics, industrial automation systems, AI-powered machines, and more.

Jeremy S. Cook

Written by

Engineer, tech writer, content creator, maker of random contraptions for fun and profit.

Hackster Blog

Hackster.io, an Avnet community, is the world’s largest network for hardware & software developers. With 1 million members and 17,000+ projects, beginners and professionals can learn and share how to build robotics, industrial automation systems, AI-powered machines, and more.

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