FlipFlop Clock Uses Mains Frequency To Keep Time

April 10, 2011 by Mike Nathan 33 Comments

One afternoon, [Sam] was a bit bored and decided he would build a clock. Not wanting to spend any money on the project, he set off to construct his clock using only the components he had on hand – this meant no micro controllers would be used whatsoever.

Built on a set of four breadboards, his clock sports a pretty short parts list. It uses just over a dozen flipflops, a few NAND chips, a 555 timer, and a small handful of other components. What you won’t find on the bill of materials however, is any sort of crystal or real-time clock. Instead of using a separate chip for keeping time, he opted to use the 60hz mains frequency as the basis for his time keeping.

The mains sine wave is passed through a series of frequency dividers to reach a 1/60hz signal, which is used to trigger the clock counters he constructed. The time is displayed on a 4-digit seven segment display, using a pair of multiplexers clocked by a 555 timer.

The clock seems to work nicely, though you have to be pretty well-versed in how the clock was built to set the time. The only means of doing so is to probe into the clock of the digit you are setting while pressing the lone pushbutton mounted on the breadboard.

While we are pretty sure no one will ever mess with his clock’s time, we have to wonder if it blinks on and off like our old VCR when the power goes out.

How Low Can You Go?

April 9, 2011 by Jason Komp 29 Comments

That’s exactly what [Kenneth Finnegan] figured out with his original investigation into low powered MSP430-based circuits. He was able to keep a count-up timer running off of 20F worth of capacitors for over 10 weeks. Although quite impressive by its own merit, many people left comments that questioned whether similar results would be seen in a circuit with functionality more advanced than simply incrementing a single digit on an LCD. Well folks, [Kenneth] has stepped it up again with this ultra low power LCD clock.

The biggest challenge in creating this clock was finding an efficient way to drive the 28 LCD segments off of the limited number of pins on his MSP430G2231 chip while still having open pins for button inputs as well. An ICM7211 LCD driver is definitely up for the task (with a few clever modifications to drive the auxiliary characters such as the center colon), but requires 8 pins to drive it. A standard 74HC595 latching shift register brings this number down to a more manageable number of 3 total pins.

Once completed the total current consumption was found to be around 12μA – low enough for a claimed run-time of approximately two and a half years from the 3V 200mAh CR2032 coin cell used. If true, a set of standard AA alkaline cells in series as found in many clocks would run this little circuit for decades.

Stick around for a short video after the break and make sure to check out the original blog entry for schematics and the complete source code!

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15-digit Nixie Clock Contains Mostly Non-useful Information

April 6, 2011 by Mike Szczys 15 Comments

[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?

Power-sipping MSP430 Mini Alarm Clock

April 4, 2011 by Mike Nathan 12 Comments

[Markus] had a TI MSP430 sitting around from the LaunchPad kit he bought a while back. He didn’t know what to do with it, but eventually decided that it would make a great miniature alarm clock.

He added a shift register to the mix in order to drive his 7-segment LCD display, using two of the MSP430’s output pins in the process. Four more pins were tied to the display’s cathodes, while the remaining two pins are connected to push buttons which register user input.

He crammed the clock’s logic as well as an alarm tune into the chip’s scant 2KB of memory space, literally occupying everything up to the last available byte. The clock is quite a power-miser, using just 2 µA in standby mode. According to [Markus’] calculations, that should enable the clock to use one set of batteries for 10+ years.

While this isn’t the first MSP430 clock we have seen, it certainly is the smallest and most simple. Stick around to see a quick video of his clock in action.

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Hackaday Links: March 20, 2011

March 20, 2011 by Mike Nathan 21 Comments

SNES Arcade Cabinet

[Daniel] let us know that he finished up a SNES arcade cabinet he has been working on for awhile. It looks so good, he says that his wife has even agreed to let him keep it in the house!

DIY Overhead projector beamer

[Liquider] sent us some information about a DIY beamer he built using an overhead projector and an old LCD panel. It looks like a great way to get a big-screen wall display set up in no time.

WordClock gets a makeover

[Doug] wrote in to share with us some progress he has made on his WordClock. You might remember our coverage of this creative timepiece a little while back. This time around, he has built a new control board, and is using vinyl stencils for a much cleaner look.

Interactive water fountain

[Gerry Chu] is well known for his water-based imagery and projects. His most recent project is a water fountain that interacts with passers by. There are no real build details as of yet, but we hope to see some soon.

Sixty Symbols explains why glass is transparent

Do you think you know why glass is transparent, but a brick is not? If you looked it up via Google, you are likely mistaken. A professor from the University of Nottingham explains why the Internet is so, so wrong about this, as well as how energy gap determines if photons of light can make it through a piece of glass. [via i09]

Sleek Numitron Clock Tells The Time And Temperature

March 13, 2011 by Mike Nathan 6 Comments

Instructables user [janw] is a big fan of nixie clocks, but he had never built one before. He decided he would rather start small and build a clock using numitron tubes first, before moving to nixies. He preferred the simpler tubes due to their much lower voltage requirements and the fact that he would not have to use any specialized power supply for his project.

His clock serves double-duty, functioning as a thermometer as well. Timekeeping is regulated with a DS12307, and temperature is monitored using a DS18B20 single wire sensor – both of which are pretty common in these sorts of projects. Both are wired to an Atmega48 MCU which serves as the brain of the clock.

The numitrons were mounted in a handsome 5-layer milled acrylate stand with a pair of buttons mounted on the bottom which allow him to set the time. It really is a spectacular looking timepiece, and a great first effort on [janw’s] part.

Be sure to stick around to see a video of the clock in action.

Continue reading “Sleek Numitron Clock Tells The Time And Temperature” →

A VFD Clock That Tells The Time, Then Tells You To **** Off

February 25, 2011 by Mike Nathan 12 Comments

Clocks are relatively simple devices – they tell time, and most often sport a handful of other utilitarian features like alarms and radios. Rarely though, do you see a clock that will wake you up in the morning and also curse at you shortly thereafter. [Matt Evans] clearly thought that clocks need to pack a little more attitude, so he built his girlfriend a clock that not only tells time, but spouts off nasty phrases as well. What a lucky gal!

The clock was constructed using IV-17 VFD tubes, each bearing 16 light-able segments. It seemed wasteful to simply use the tubes to tell time, so [Matt] got busy adding other features to the clock. It has an alarm, a calendar that is always stuck on his girlfriend’s birthday, and an ambient light sensor to dim the tubes at night. It also sports a variable rudeness setting, allowing for mild insults when family members are present, and extremely foul language for when your frat brothers swing by.

He has plenty of pictures on his site, but we’re betting people will want to see schematics and some source code. After all, Mother’s Day is but a few months away!