It has become a bit of a running joke in the Hackaday community to suggest that a project could or should have been done with a 555 timer. [Tim] has rather taken this to heart with his latest Electronic Dice project, which uses three of the venerable devices.
If three seems like a lot of 555s to make an electronic die, then it may be worth considering that the last time we shared his project he was using 22 of them! Since then, [Tim] has been busy optimising his design, whilst keeping within the constraints of an old-school through-hole soldering kit.
Maybe the most surprising thing about this project is the purpose to which the NE555 devices are pressed. Rather than using them for their famous oscillation properties, they are in actual fact just being used as Schmitt Triggers to clean up the three-phase ring oscillator that is constructed from discrete transistors and passives.
The ring oscillator cleverly produces three phase-shifted square waves such that a binary combination of the three phases offers six unique states. Six being the perfect number for a dice throw, all that then remains is to figure out which LEDs need to be switched on in which state and wire them up accordingly.
To “roll” the dice, a push-button powers up the oscillator, and stops it again when it is released, displaying the random end-state on the LEDs.
It can be fun to see what can be done using old technology, and educational to try to optimise a design down to the fewest parts possible.
[Tim]’s earlier project is here if you want to see how the design has evolved. The documentation on both of these iterations is excellent and well worth a read.
One of the most common clichés around here is that a piece of equipment chosen for a project is always too advanced. If a Raspberry Pi was used, someone will say they should have used an Arduino. If they use an Arduino, it should have been an ATtiny. And of course, if an ATtiny was used, there should have simply been a 555 timer. This time, however, [Tim] decided to actually show how this can be done by removing some of the integrated circuits from an electronic dice and relying entirely on the 555 timer for his build.
The electronic dice that [Tim] has on hand makes use of two main ICs: a NE555 and a CD4017 which is a decade counter/divider used for cycling through states. In order to bring the 555 to the forefront of this build, he scraps the CD4017 and adds an array of 555 timers. These are used to generate the clock signals necessary for this build but can also be arranged to form logic circuits. This comes at a great cost, however. The 555 chips take up an unnecessarily large area on the PCB (even though these are small surface-mount chips), consume an incredible amount of power, and are very slow. That’s fine for an electronic dice-rolling machine like this one, but that’s probably where [Tim] will leave this idea.
If you spend enough time trolling eBay for interesting electronic devices to take apart, you’re bound to start seeing suggestions for some questionable gadgets. Which is how I recently became aware of these tiny GPS jammers that plug directly into an automotive 12 V outlet. Shipped to your door for under $10 USD, it seemed like a perfect device to rip open in the name of science.
Now, you might be wondering what legitimate uses such a device might have. Well, as far as I’m aware, there aren’t any. The only reason you’d want to jam GPS signals in and around a vehicle is if you’re trying to get away with something you shouldn’t be doing. Maybe you’re out driving a tracked company car and want to enjoy a quick two hour nap in a parking lot, or perhaps you’re looking to disable the integrated GPS on the car you just stole long enough for you to take it to the chop shop. You know, as one does.
But we won’t dwell on the potentially nefarious reasons that this device exists. Hackers have never been too choosy about the devices they investigate and experiment with, and there’s no reason we should start now. Instead, let’s take this piece of gray-area hardware for a test drive and see what makes it tick.
The heart of the build (pun intended) is a lens assembly salvaged from a CD player, which uses a coil and permanent magnet to move the lens in order to read across a disc. In this case, the coil is instead fed pulses from an astable multivibrator circuit built with a hacker favourite, the 555 timer IC. It’s all assembled on a breadboard, which is a great way to build such projects that rely on experimentation through the swapping of component values.
We haven’t seen too many projects using optical drive lens assemblies, but we’re sure there must be other applications. If you end up using one to agitate biological samples or build an awesome laser projector, be sure to hit up the tips line. Video after the break.
Whether or not you chose to believe our claim that we planned it this way, the holidays happen to fall right smack in the middle of our ongoing Circuit Sculpture Contest, which challenges hackers to build circuits that double as bona fide works of art. It’s become almost too easy to spin up your own PCB, so why not try your hand at building in three dimensions and without a net? The holidays are a perfect time for it as it’s not only a reprieve from the work, school, or forced labor camp that usually ties up our waking hours, but can also be a source of inspiration.
Case in point, this festive LED Christmas tree entry that comes our way courtesy of [Vincent Mkes]. This one really has it all: a recognizable theme, fantastic wire work, copious amounts of LEDs, and in a touch that is sure to delight even the electronics Scrooges amongst our readership, he does it all with the venerable 555 timer. It’s really what the Circuit Sculpture Contest is all about: taking a circuit that might otherwise be pretty ordinary and turning it into something truly unique.
The astute Hackaday reader (as if there was any other type) will likely notice there are actually two NE555 timers under the tree, each blinking their respective bank of LEDs at a different frequency. This makes the final result a bit more vibrant, and through some last-minute revisions, [Vincent] was able to hook them both up to a single power supply to really capture the minimalist spirit of the Contest.
As an early Christmas gift to us all, [Vincent] has done an excellent job documenting this build so anyone who wishes to infuse their end of year party with a little diode-driven holiday cheer can follow along. He’s included build instructions as well as diagrams of the circuit, though we encourage anyone looking to make one of their own to experiment a bit and put their own spin on it. After all, this is supposed to be art.
There’s still plenty of time to get your own entry into the Circuit Sculpture Contest, Yule-related or otherwise. Just document your build on Hackaday.io and submit it before the January 8th, 2019 deadline. Remember that entries can’t just look cool, they still need to be functional. Words to live by in general, but doubly important when they’re the rules of a contest.