Simple clock uses RTC chip and character display

[Giorgos Lazaridis] just finished building a simple clock on a breadboard. It uses a common real time clock chip, the DS1307. This is less expensive that its full-featured older brother, the DS3232. The difference between the two is that the 1307 requires an external 32.768 kHz crystal and it is not temperature compensated. This means it will not be quite as accurate over the long-haul (it may wander as much as one minute per month), but it still blows the accuracy of using a microcontroller as an RTC out of the water and includes a backup battery which will keep time when the rest of the circuit is switched off.

This design uses a PIC 16F1937 to display the time and date on a 16×2 character LCD screen. Six buttons are dedicated to incrementing one specific chunk of data (ie: one button changes the year, another the day, etc.). A seventh button can be held down when using the other six in order to decrement the setting. We’re always interested in how the button code is written. [Giorgos] did share his code, but he wrote it in assembly so it’s of little use to us as we tend to stick to C code.

See the walk through video after the break.

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15-digit Nixie clock contains mostly non-useful information

[Jarek Lupinski] is at it again, this time building a clock using 15 Nixie tubes. Just look at the time…. wait, how do you read this now? It’s not seconds since the epoch, but an homage to a very expensive New York City art piece. [Jarek] took his inspiration from the Metronome art installation in Union Square.

We hadn’t heard of it before and were shocked to learn that this art was commissioned at $4.2 million. It belches steam and confuses passersby with its cryptic fifteen digits. It seems that the eight digits on the left mark the current time – two digits for hours, two for minutes, two for seconds, and the final digit for hundreths of a second. The seven remaining digits count down the time left in the day. So when you watch it, you see the significant digits of the display increasing, and the insignificant half decreasing.

The Nixie version rests snuggly on a 15″x4″ PCB. We’re sure it doesn’t number in the millions, but that couldn’t have been cheap to have manufactured. Each tube has its own driver chip, removing the need for multiplexing. An ATmega168 controls the clock (along with some shift registers to expand the I/O count), reading time from a DS1307 RTC chip. It looks fancy, but where’s the belching smoke on this version?

Xbee controlled, granite-wrapped clock travels into future

From the looks of it this clock is a couple of months ahead of its time. [Oscar] built the clock (translated) taking time to add a lot of goodies into the mix. First up, the parts you see include six large 7-segment displays for hours, minutes, and seconds as well as an LED marquee which can scroll messages. Inside there’s a temperature and humidity sensor for environmental feedback, and an Xbee module which allows for wireless computer control. Time is kept by a DS1307 real-time clock, which is read by an Arduino Uno, then pushed to the display by the pair of I2C addressable SAA1064 drivers. The whole thing was enclosed in four sheets of granite for the box, and a pane of glass for the front. We sure hope it’s well anchored to that wall. You can see it ticking away after the break.

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Equinox clock

The Equinox clock is made up of simple parts but a combination of fine design and precision make it a gem of a timepiece. The guts are made up of an Arduino, a DS1307 real time clock, twelve LED drivers, and sixty RGB LEDs. These combine with a capacitive touch interface to tell the time using three lit blocks for the hours, one for the minutes, and a fading block for the seconds. See for yourself after the break.

To our delight, [Bram Knaapen] shared the specifics of the case. The black ring that makes up the body was laser cut and spray painted. He uses small blocks of acrylic that have been sandblasted to diffuse the light. This is also a great example of clean circuitry using interconnects between the different circuit boards.

We always enjoy seeing clocks no matter what level of finish is involved, but great design is something that makes us want to hang a project on the wall rather than stow it in a parts bin.

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DS1307 breakout board

Adafruit’s got a handy breakout board for the DS1307 RTC available. This chip isn’t nearly as accurate as the DS3231 used in the Chronodot but it’s quite a bit cheaper. The breakout makes this easy to breadboard or plug into an Arduino and has everything you need; clock crystal, a backup battery, filtering capacitor, and pull-up resistors. Our favorite part is that Adafruit designs are open source so you can etch the board yourself if you checkout the files from their git repository. This will make a great addition to our prototyping hardware collection.

Incidentally, we were surprised to see the choice of 2.2k resistors for the I2C bus pull-ups. We were under the impression that 4.7k was a standard value here. We’d love to hear your thoughts on this in the comments.

[via Dangerous Prototypes]

Six digit LED clock

Got a bag of LEDs handy? Why not build a display with them? We’ve seen a lot of clocks that make use of LED modules but soldering your own is a fun pastime. [Vadim Suhovatih] did just that using 130 LEDs to build this clock. Each segment of the 7-segment digits consists of three LEDs in parallel which are switched by some 2N4401 transistors. An ATmega328 in the form of an Arduino controls the device with the aid of a DS1307 real-time clock for timekeeping and a 4017 decade counter to assist with scanning the display. Check out the demo after the break.

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BlokClok – Abstract time display

blokclok_abstract_time_display

Clocks made from blinking LEDs always make for fun projects. [Earthshine] built a clock that displays time abstractly using an 8×8 RGB LED matrix. The video embedded after the break illustrates how to read the time but here’s the gist of it: One LED is illuminated in the outside box of LEDs and moved in a clockwise motion to approximate seconds. Inside of this, there are four quadrants; upper left indicates hour-tens digit, upper right hour-ones, lower left minute-tens, and lower right minute-ones. This certainly makes for an interesting conversation piece!

There is no schematic and no code available but it’s really the concept that we’re interested in. If you must know, [Earthshine] bases this build around an Arduino. A DS1307 real time clock keeps the time, while four 74HC595 shift registers are utilized to control the three LED colors and the multiplexing.

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