A wristwatch similar to the Berlin Uhr, with the actual Berlin Urh in the background

Tiny Berlin Clock Replica Also Counts Seconds

If you’re a clock aficionado and have ever visited Berlin, you’re probably familiar with the Berlin Clock on Budapester Straße: a minimalist design of yellow and orange lights that displays the time in a base-5 number system. This clock has been telling the time to the few that can read it since 1975, and is but one of several unusual clocks that can be found in the city.

Berlin resident [jjoeff] decided to make a miniature replica, appropriately called the Berlin Uhr Nano, in order to watch the unusual display at any time of day. Built around a Wemos D1 Mini, it connects to WiFi in order to synchronize its internal clock to an NTP time server. It then drives a custom PCB that holds 39 WS2812 LEDs to display the time in its proper format. Unlike the original though, it also includes a full counter to tell the number of seconds; the bigger clock just flashes a single lamp to show the seconds passing.

Powered by a 500 mAh lithium battery, it can be converted into a wristwatch by simply threading a strap through slots in the PCB. With no buttons for adjustment or any functionality other than displaying the time, it serves the same purpose as the original, just in a portable format. We’ve seen a slightly larger Berlin Clock replica made of wood before, as well as a round one that uses the same base-5 encoding scheme. Continue reading “Tiny Berlin Clock Replica Also Counts Seconds”

Light Duty Timekeeping: Arduino Berlin Clock

Just when we thought we’d seen all the ways there are to tell time, along comes [mr_fid]’s Berlin clock build. It’s based on an actual clock commissioned by the Senate of Berlin in the mid-1970s and erected on the famous Kurfürstendamm avenue in 1975. Twenty years later it was decommissioned and moved to stand outside the historic Europa-center.

This clock tells the time using set theory and 24-hour time. From the top down: the blinking yellow circle of light at the top indicates the passing seconds; on for even seconds and off for odd. The two rows of red blocks are the hours—each block in the top row stands for five hours, and each block below that indicates a single hour. At 11:00, there will be two top blocks and one bottom block illuminated, for instance.

The bottom two rows show the minutes using the same system. Red segments indicate 15, 30, and 45 minutes past the hour, making it unnecessary to count more than a few of the 5-minute top segments. As with the hours, the bottom row indicates one minute per light.

Got that? Here’s a quiz. What time is it? Looking at the picture above, the top row has three segments lit. Five hours times three is 15:00, or 3:00PM. The next row adds two hours, so we’re at 5:00PM. All of the five-minute segments are lit, which adds 55 minutes. So the picture was taken at 5:55PM on some even-numbered second.

The original Berlin clock suffered from the short lives of incandescent bulbs. Depending on which bulb went out, the clock could be ‘off’ by as little as one minute or as much as five hours. [mr_fid] stayed true to the original in this beautiful build and used two lights for each hour segment. This replica uses LEDs driven by an Arduino Nano and a real-time clock. Since the RTC gives hours from 0-23 and minutes and seconds from 0-59, a couple of shift registers and some modulo calculations are necessary to convert to set theory time.

[mr_fid] built the enclosure out of plywood and white oak from designs made in QCAD. The rounded corners are made from oak, and the seconds ring is built from 3/8″ plywood strips bent around a spray can. A brief tour of the clock is waiting for you after the break. Time’s a-wastin’!

Continue reading “Light Duty Timekeeping: Arduino Berlin Clock”