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.

Hackaday Reader Throwdown: Electronic Dice

April 10, 2011 by Mike Nathan 5 Comments

electronic_dice

Hackaday reader [Daid] posted in our forums showing off a set of electronic dice he recently constructed. Back in January, we featured a similar set of electronic dice built with an Arduino that was way overpowered as far as [Daid] was concerned. Not satisfied with simply saying it could be done better, he put his money where his mouth is – something we would love to see more of.

He used an ATTiny2313 to provide the device’s logic, outputting the dice values on a set of four 7 segment displays. The whole setup is controlled by a single push button that serves triple duty rolling the dice, configuring how many sides the dice have, as well as selecting how many dice are being thrown.

He admits that the wiring job is a bit of a mess, but he was going for function over form, and it works just fine. He also says that he would have finished it far sooner if it hadn’t been for ~~those meddling kids~~ some broken 7 segment displays.

We think he did quite a nice job, though we’re all ears if you think you can do it better.

Frequency Counter For $10 Worth Of Parts

March 14, 2011 by Mike Szczys 10 Comments

[Scott] built this frequency counter using less than $10 in parts. It’s set up to meter frequencies in megahertz which is fitting since he’s planning to use it with his radio hardware experimentation. But we would find it useful too because our cheap multimeter only reads up to around 4 MHz.

He’s using an ATmega16 that he had on hand but it has features way beyond the specs for the device. He speculates that an ATtiny2313 would easily work in its place. The microcontroller is mostly used to drive the multiplexed 7-segment display after reading the frequency values from the 74LV8154 counter chip that he is using. He doesn’t have a full schematic for the device, but there is a hand drawn diagram for using the frequency counter; the rest should be easy to piece together. Looking at that circuit we don’t think it would be too hard to make this a manual-ranging frequency counter to give you more use out of the dedicated device. Check out [Scott’s] demonstration video which is embedded below the fold.

Continue reading “Frequency Counter For $10 Worth Of Parts” →

Ego Box Monitors Web Hits

January 29, 2011 by Mike Szczys 12 Comments

[Bogdan’s] latest project is a box that displays web hits for a chosen site. He calls it the Ego Box because depending on how traffic goes it either bloats or crushes your ego. This provides similar functionality as our Troll Sniffing Rat but the biggest difference is that this is a stand-alone Ethernet device. That’s thanks to the ENC28J60 Ethernet controller chip which manages the stack and has been quite popular in DIY electronic projects. In order to monitor your hits [Bogdan] crafted a bit of code to add to the header of your index page. It increments the counter file each time the page is loaded, and the Ego Box simply monitors that file, displaying the traffic on an eight digit 7 segment display.

[via Adafruit]

Xbee Controlled, Granite-wrapped Clock Travels Into Future

January 27, 2011 by Mike Szczys 59 Comments

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.

Continue reading “Xbee Controlled, Granite-wrapped Clock Travels Into Future” →

Electronic Dice Has Option For 20 Or 100 Sides

January 17, 2011 by Mike Szczys 17 Comments

[Bluewraith] built himself an electronic dice using a 555 timer and 4017 counter. This is a classic project and he enjoyed doing it but wondered about making a 20-sided dice. So he grabbed his Arduino and got to work. A switch on the final project selects between 20 or 100 sides. He used a MAX7219 to control the 7-segment displays, and a standalone AVR chip for the rest of it.

If you missed it back in October you should also look in on this 6-sided dice. It also uses an AVR running the Arduino bootloader but a mercury switch allows the player to shake the box in order to start a roll.

One last note, we made a conscious decision to use the word ‘Dice’ instead of the grammatically correct ‘Die’ which is its singular version. We think ‘Die’ can be a bit too confusing and we’re not the only ones.

Wristwatch Board With Throwback Digits

August 25, 2010 by Mike Szczys 22 Comments

This wristwatch circuit board has some pretty interesting digits. They’re older components that give a classic look to your wristwatch display. On board you’ll find a PIC 16F628A running with an external clock crystal. The display isn’t always illuminated (kind of like Woz’s watch) in order to save the batteries, but can be woken up for a short time with the push of a button. The steam-punk-ish body seen to the left is the just first try. This guy has four more boards left so it should be fun to see what he comes up with.

[Via Hackaday Flickr Pool]