ATMega16 Hard Disk Clock

November 23, 2013 by James Hobson 14 Comments

[Martin Stromer] made this great looking Hard Disk Clock about 12 years ago, and finally decided to share it with the world. It’s been “ticking” ever since.

It’s a beautiful clock, and if you think the drive might look a bit odd, that’s probably because its well over 20 years old! We’re not too sure the capacity, but it couldn’t have been more than a few dozen megabytes.

To read the time, the platter rotates 30 degrees at once, per hour. The read-write head inches across the disc to display the minutes. Each of the black lines represents a quarter hour. The whole thing is controlled by an ATMega16, which maintains almost all of the original hardware. The blog post has a great write-up on how it all works.

Did we mention it’s also easy to set the time? Simply rotate the disc by hand and slide the read-write head into place, then press the reset button. Check out the clock in action after the break.

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Arduino Astronomic Clock Automates Lights

November 15, 2013 by Marsh 32 Comments

[Paulo’s] garden lights are probably a bit more accurately automated than anyone else’s on the block, because they use latitude and longitude clock to decide when to flip the switch. [Ed Note from the far future: this page no longer exists, but you can still read it on the Wayback Machine. The TimeLord library has also been superceded, so you’ll have some porting to do.]

Most commercial options (and hobbiest creations) rely on mechanical on/off timers that click on an off every day at the same time, or they use a photosensitive element to decide it’s dark enough. Neither is very accurate. One misplaced leaf obscuring your light-dependent resistor can turn things on unnecessarily, and considering the actual time of sunset fluctuates over the year, mechanical switches require constant adjustment.

[Paulo’s] solution addresses all of these problems by instead relying on an algorithm to calculate both sunrise and sunset times, explained here, combined with swiftek’s Timelord library for the Arduino. The build features 4 7-segment displays that cycle through indicating the current time, time of sunset and of sunrise. Inside is a RTC (real time clock) with battery backup for timekeeping along with an Omron 5V relay to drive the garden lamps themselves. This particular relay comes with a switch that can force the lights on, just in case.

Check out [Paulo’s] project blog for the full write-up, links to code and more details, then take a look at some other home automation projects, like the SMS-based heater controller or occupancy-controlled room lighting.

Fire Bell Wakes You For Work By Shaving Years Off Your Life

November 3, 2013 by Mike Szczys 38 Comments

If you suck at getting up in the morning [Jake Lee] has a solution that will make sure you don’t get fired from your job. Unfortunately it’s going to scare the life out of you — but maybe we’re just not hard enough sleepers to appreciate the value in an alarm clock that’s so horribly loud.

At first we wondered where he got the bell but it looks like you can buy one for about fifteen bucks. We’re not saying you should hide one of these under your best friend’s bed, but the cost of the bell does put it firmly in the worth-it-as-a-prank price range. [Jake] used rigid and flexible conduit to connect the bell to a power source, and the control panel shown on the left. He uses the LED backlight of the bedside alarm clock to drive the base of a transistor, switching a relay to trigger the bell. The big button on the grey box makes the wailing stop (seriously, cut your volume before you hit 0:30 in the clip below).

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Heathkit Clock Updated With A PIC32 And GPS

November 1, 2013 by Adam Fabio 46 Comments

One of [Bob’s] most treasured possessions is a Heathkit alarm clock he put together as a kid. Over the years he’s noticed a few problems with his clock. There isn’t a battery backup, so it resets when the power goes out. Setting the time and alarm is also a forward only affair – so stepping the clock back an hour for daylight savings time means holding down the buttons while the clock scrolls through 23 hours. [Bob] decided to modify his clock with a few modern parts. While the easiest method may have been to gut the clock, that wouldn’t preserve all those classic Heathkit parts. What [Bob] did in essence is to add a PIC32 co-processor to the system.

Like many clocks in the 70’s and 80’s, the Heathkit alarm clock was based upon the National Semiconductor MM5316 Digital Alarm Clock chip. The MM5316 operates at 8 – 22 volts, so it couldn’t directly interface with the 3.3V (5V tolerant) PIC32 I/O pins. On PIC’s the input side, [Bob] used a couple of analog multiplexer chips. The PIC can scan the individual elements of the clock’s display. On the PIC’s output side, he used a couple of analog switches to control the ‘Fast’, ‘Slow’, and ‘Display Alarm/Time’ buttons.

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An Overly-Complicated Logic Chip Clock

October 29, 2013 by Brian Benchoff 27 Comments

When a normal alarm clock just won’t do, the only option is to build your own, entirely out of discrete logic chips. [jvok] built this alarm clock for last year’s 7400 Logic Competition. In a desire to go against the grain a little bit, [jvok] decided to use 4000-series logic chips. It was allowed under the rules, and the result is a wonderful example of what can be done without a microcontroller.

Most clock projects we’ve seen use a single button to increase each digit. [jvok] wanted to do something unique, so he is able to set his clock with a ‘mode’ button that allows him to independently set the hours, minutes, and seconds. He’s only ever seen this method of setting a clock’s time used with microcontroller-based projects, and translating even that simple code into pure circuitry is quite impressive.

This clock also includes an alarm function, set by a bunch of DIP switches in binary coded decimal. It’s a great piece of work, and deserving of much more attention than it received during the Open Logic Competition.

Game Of Life Clock

October 19, 2013 by James Hobson 12 Comments

[Alex] wanted to make an LED clock. But simply making an LED array clock was far too easy — so he decided to make it follow some interesting rules…

Ever heard of John Conway’s Game of Life? It’s quite simple — there are four rules.

Any live cell with fewer than two live neighbours dies, as if caused by under-population.
Any live cell with two or three live neighbours lives on to the next generation.
Any live cell with more than three live neighbours dies, as if by overcrowding.
Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.
[from Wikipedia]

So [Alex] decided to make his clock LED matrix follow these rules, with lit pixels representing life. Every minute, on the minute, the time is displayed. But as soon as it is displayed, the rules take over, and the display disintegrates, following the rules of the Game of Life. It makes for an very interesting display that’s just waiting to be scaled up to a larger size!

He’s done a great job writing it up on his blog, and has included his code as well — so if you’re so inclined, take a look! If not, stick around after the break to see the clock in action.

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The Greenest Wall-Powered Clock

October 13, 2013 by Brian Benchoff 51 Comments

Some of the most inefficient appliances in the home are AC mains-powered clocks. You can’t exactly turn them off and they use a whole lot of energy considering how often they’re looked at. [t3andy] came up with a great low power AC Mains clock that is only on 3% of the time. As a neat bonus, it also looks really, really cool.

[t3andy] is using a Teensy 3 as the brains of this clock, and the serial interface on the board provides a relatively easy means of setting the time without having to use buttons or tact switches. The clock face consists of 13 neopixels, with two red pixels showing the hour and a single green pixel showing the minutes. The time is measured with a DS3232 I2C real time clock with a battery backup.

The design is remarkably efficient since the LEDs are off 97% of the time, only being lit at the top of the minute. There are provisions for IR control and a PIR sensor to display the time whenever it’s needed, but that would obviously mean a hit to the energy efficiency.