Berlin Clock or Set Theory Clock - the world's first clock to display the time with luminous fields - Guinness Book of Records

The Berlin Clock, also known as the Set Theory Clock, is a public clock in Berlin . It was developed in 1975 by the inventor Dieter Binninger on behalf of the Berlin Senate and displays the time using a number of illuminated lamps.

The clock, which has been included in the Guinness Book of Records and has a total height of seven meters – including the mast – was initially erected on June 17, 1975, on the median strip of Kurfürstendamm at the corner of Uhlandstraße , as the “first clock in the world to display the time with luminous colored fields”.

The clock required many incandescent bulbs, making it very maintenance-intensive and resulting in annual maintenance costs of approximately €5,000 for Binninger GmbH, which bore all the expenses. For this reason, Binninger invented devices and methods to extend the lifespan of general-purpose incandescent bulbs between 1980 and 1982. Binninger died in 1991, and since neither the city nor the Charlottenburg district was willing to cover the costs of its continued operation, the clock was decommissioned in 1995. Thanks to an initiative by local business owners, it was reinstalled in 1996 in front of the Tourist Information Center in the Europa-Center on Budapester Straße in Berlin. Also located in the Europa-Center is the liquid-powered "Clock of Flowing Time ."

Because of its unusual design at a time when digital clocks were still uncommon, small replicas of the clock became very popular for home use. Dieter Binninger's Berlin-Uhr GmbH also manufactured it as a tabletop and wall-mounted model for home use, which was sold in Berlin souvenir shops. The devices contain aTexas Instruments TMS1000 microprocessor.

After Binninger's accidental death, production of the Berlin clocks was taken over by the Kindermann company in Berlin-Rudow . Sales and repairs of the wall and table clocks continued until 2002, when distribution was discontinued. Since 2007, sales and repairs of the table clocks have again been handled by the Asmetec company in Kirchheimbolanden .

A watch design was created for smartwatches with Wear OS and offered as a free app download in three different color variations.

Contrary to the claim in the official Binninger BERLIN-UHR GmbH brochure for their table clock, "The world's first clock that works according to the principles of set theory," the clock has nothing to do with set theory . Time is displayed using a base-5 positional numeral system . Hours and minutes are represented by illuminated segments arranged in four horizontal strips. The first, second, and fourth rows each contain four lights, while the third row contains eleven. The first two rows use red lights to indicate the hour, with one illuminated segment in the upper strip representing five hours and one in the lower strip representing one hour. The current hour is calculated by adding these values. Similarly, the minutes are displayed in the two lower rows using yellow segments in increments of five and one. The lights for 15, 30, and 45 minutes are red for better readability. Above the rows is a circular flashing light that switches on and off every second.