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’!

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A Clockwork Cradle is Baby’s First Escapement

[Scott] doesn’t have any kids, but he’s the sort of type that likes to get ahead of the game. Of course this means spending time in his garage to build a rocking cradle. Usually, these are acquired from a baby shower and are powered by batteries. Terribly uncool, considering a mechanism to keep a pendulum swinging has existed for hundreds of years now. His latest project is the escapement cradle – a cradle (or hammock) that keeps rocking with the help of falling weights.

cradle-escapementThe first video in this series goes over the inspiration and the math behind determining how much energy it will take to maintain a swinging pendulum. The second video goes over a very rough prototype for the escapement mechanism with some woodworking that looks dangerous but is kept well under control. The third video puts everything together, rocking a cradle for about 10 minutes for every time the weight is lifted to the top.

[Scott] has had a few of his projects featured on Hackaday, and he’s slowly becoming the number two mechanized woodworker, right behind [Matthais]. He recently put the finishing touches on the expanding wooden table we saw a year ago, and there are surely even cooler builds in the queue for his YouTube channel.

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A Networked Analog Clock

Even in the face of an Internet of Things grasping for a useful use case, an Internet-connected clock is actually a great idea. With a cheap WiFi module and a connection to an NTP server, any clock can become an atomic clock. [Jim] decided to experiment with the ESP8266 to turn a cheap analog clock into something that will display network time using a bunch of gears and motors.

The clock [Jim] chose for this build is an extremely cheap clock pulled right from the shelves of WalMart. This clock uses a standard quartz clock mechanism, powered by a single AA cell. The coils in these quartz movements can be easily controlled by pulsing current through them, and with a few a few transistors and diodes set up in an h-bridge, an ESP8266 is quite good at setting the time on this clock.

The software for this clock first connects to the WiFi network, then checks an NTP server for the true time. Once the ESP8266 gets the time, it starts hammering the coil in the clock movement until the hands are where they should be.

[Jim] says the project needs a bit of work – there is no feedback on the clock to determine the position of the hands. Instead, the time is just set assuming the clock hands started off at 12:00. Still, even with that small fault, it’s a great build and a great exploit of what can be done with a cheap quarts clock movement.

If you’d like to go to the opposite extreme of cost and complexity, how about a DIY retro atomic clock?  Or if you’re in need of a wakeup, we’ve seen a ton of alarm clock posts in the past few weeks.

Hacklet 84 – Alarm Clocks

The stereotypical hardware hacker is a creature of the night. Some of us do our best work in the wee hours. The unfortunate side effect of this is that we have a hard time getting up in the morning. Sometimes life demands a hacker be up-and-at-em before noon though. In these cases, the only solution is an alarm clock. This week’s Hacklet features some of the best alarm clock projects on Hackaday.io!

mercyWe start with [hberg32] and Merciless Pi Alarm Clock. Merciless is a good name for this Raspberry Pi based clock. We have to say it’s quite snazzy with its laser cut case and large seven segment LED face. When the alarm goes off though, this Pi bites back.

Titanium drivers powered by a 20 watt amplifier will wake even the heaviest sleepers. If that’s not enough, [hberg32] added a bed shaker to vibrate you out of the sack. The snooze button only works 3 times, after that you can press all you want, the music will still play. As if that wasn’t enough, this clock even has a pressure sensor. If you get back in bed, the alarm starts up again. Truly fitting of the name “merciless”.

irss[Ceady] took the kinder, gentler route with Integrated Room Sunrise Simulator. This alarm clock simulates dawn, gently waking the user up. A Lutron Maestro series wireless dimmer allows the sunrise simulator to slowly increase the room’s light level over a period of 10 minutes, allowing [Ceady] to wake up silently.

The clock itself uses an ATmega168 for control. [Ceady] spent a considerable amount of time testing out different methods of creating a seven segment LED display. When casting with cornstarch and resin didn’t do the trick, he went to commercial LED diffuser film from Inventables. The film proved to be just what he was looking for.

chumby2Next up is [Spiros Papadimitriou] with DIY Chumby-lite. Taking inspiration from [Bunnie Huang] and the Chumby project, [Spiros] created a friendly alarm clock with a touchscreen LCD. Much like the Chumby, this clock packs a WiFi module.

In this case though, the WiFi module is an ESP8266, whose on-board Xtensa microcontroller runs the whole show. [Spiros] programmed his Sparkfun ESP8266 Thing in C++. To keep costs down, [Spiros] left out anything unnecessary – like a real-time clock module. The Chumby-lite uses NTP to stay regular. The reductions paid off – this clock can be built for around $13.00, not including the very nice 3D printed case.

1983[Wanderingmetalhead] takes us all way back to 1983 with his 7 Day Alarm Clock. 32 years ago, this was [wanderingmetalhead’s] first embedded system project. As the name implies, this clock stores a different wake time for each day of the week. Actual numeric entry sure beats the old “hold two buttons and watch the numbers spin” system.

This is an oldie. The system is based upon a Motorola (which became Freescale, and is now NXP) 6802 micro. The code was written in assembly and cross-assembled on an Apple II. A 3.58MHz colorburst crystal divided down to 60 Hz provides the time base. This setup wasn’t perfect, but good down to a about a minute a month. The whole project lived and worked in an old amplifier case, where it dutifully woke [wanderingmetalhead] each day for 17 years.

If you want to see more alarm clock projects, check out our new alarm clocks list! If I didn’t wake up early enough to catch your project, don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Analog Clocks Play Their Own Beat

Play the demo video below and try not to let the rhythm worm its way into your brain. What you’re hearing is the sound of a bunch of clocks, amplified. None of them are keeping wall time, but all of them are playing together.

[Gijs] makes crazy musical instruments. He doesn’t give us much more than a video and a couple schematics for this project, so this one’s still a bit of an enigma, but here’s what we’ve put together.

Klok slave unit schematic
Klok slave unit schematic

The video looks like eight identical version of the same module. The input takes a voltage and converts the rising and falling edges into pulses to drive the coil of an el-cheapo clock. The LEDs pulse as the poles of the clock switch to the incoming beats. The output comes from an amplified piezo sensor stuck on the back of each clock. That is, what you’re hearing is each clock ticking, but amplified. And if you watch the dials spin, it doesn’t look like any of them are telling time.

So far so good, and it matches up with the schematic. But what’s up with that switch on the front? It doesn’t show up anywhere.

And what’s driving the show? [Gijs] tantalizes us with a master clock module (on the same page) that looks like it does keep time, and outputs subdivisions thereof. But that would be too slow to be what’s used in the video. Has he swapped the crystal to make it run faster? It’s a mystery.

Of course, we’d expect no less from the man who mics up a kitchen timer or a gear motor and adds them to his synthesizer rack. We’ve covered a bunch more of [Gijs]’s work in the past, from his video mixers to this hard-drive turned synth oscillator, but this time he’s got us scratching our heads a bit, as well as tapping our feet.

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Weather Word Clock Warns You Of Impending Winter

Word clocks are pretty popular “artsy” ways of telling time, but [doktorinjh] wanted to try something a little different. So instead of showing the time — it shows the weather.

He’s using an Arduino Yun to access the Weather Underground API for data and then sends the data out to a grid of 100 individually addressable RGB LEDs — NeoPixels to be precise. The LEDs are overlayed with a laser cut acrylic sheet with various words and weather icons to allow for a pretty specific depiction of current (or future) weather conditions.

The frame is made out of colonial style molding and since it’s a weather clock, he turned the grid of LEDs into a rainbow effect, because, why not?

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Strobe Light Slows Down Time

Until the 1960s, watches and clocks of all kinds kept track of time with mechanical devices. Springs, pendulums, gears, oils, and a whole host of other components had to work together to keep accurate time. The invention of the crystal oscillator changed all of that, making watches and clocks not only cheaper, but (in general) far more accurate. It’s not quite as easy to see them in action, however, unless you’re [noq2] and you have a set of strobe lights.

[noq2] used a Rigol DG4062 function generator and a Cree power LED as a high-frequency strobe light to “slow down” the crystal oscillators from two watches. The first one he filmed was an Accutron “tuning fork” movement and the second one is a generic 32,768 Hz quartz resonator which is used in a large amount of watches. After removing the casings and powering the resonators up, [noq2] tuned in his strobe light setup to be able to film the vibrations of the oscillators.

It’s pretty interesting to see this in action. Usually a timekeeping element like this, whether in a watch or a RTC, is a “black box” of sorts that is easily taken for granted. Especially since these devices revolutionized the watchmaking industry (and a few other industries as well), it’s well worthwhile to take a look inside and see how they work. They’re used in more than just watches, too. Want to go down the rabbit hole on this topic? Check out the History of Oscillators. Continue reading “Strobe Light Slows Down Time”