photograph of custom PCB assembly of NE555-based electronic dice

NE555-Based Electronic Dice

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.

scope trace of the electronic dice ring oscillator
Simulation trace of the three-phase ring oscillator before Scmitt Trigger stages

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.

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Back To Basics Hack Chat

Join us on Wednesday, July 15 at noon Pacific for the Back to Basics Hack Chat with Simplifier!

Stay in the technology business long enough and eventually you’ll have to face an uncomfortable question: “Have I built anything permanent?” Chances are good that most of us will have to answer in the negative. For all the flash and zazzle we put into our projects, and for all the craftsmanship we try to apply to our systems, all of it is built on a very fragile foundation of silicon that will be obsolete within a decade, held together by slender threads of code in a language that may or may not be in fashion in a year’s time, and doesn’t even really exist in anything more tangible than a series of magnetic domains on a hard drive somewhere.

Realizing you’ve built nothing permanent is the engineer’s equivalent of a midlife crisis, and for many of us it sets off a search for an outlet for our creativity that we can use to make things that will outlast us. One hacker, known only as “Simplifier”, turned his search for meaningful expression into a quest to make technology better by making it more accessible and understandable. His website, itself a model of simplicity, catalogs his quest for useful materials and methods and his efforts to employ them. He has built everything from homebrew vacuum tubes to DIY solar cells, with recent forays into telecom tech with his carbon rod microphone and magnetostrictive earphone.

In this Hack Chat, Simplifier will answer your questions about how turning back the technology clock can teach us about where we’re going. Join us as we explore what it takes to build the infrastructure we all take so much for granted, and find out if there’s a way to live simply while still enjoying a technologically rich life.

join-hack-chatOur Hack Chats are live community events in the Hack Chat group messaging. This week we’ll be sitting down on Wednesday, July 15 at 12:00 PM Pacific time. If time zones have you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.


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