relay logic

4 Articles

A Clock Made Out Of Electromechanical Relays

February 13, 2024 by 11 Comments

Electromechanical circuits using relays are mostly a lost art these days, but sometimes you get people like [Aart] who can’t resist to turn a stack of clackity-clack relays into a functional design, like in this case a clock (article in Dutch, Google Translate).

It was made using components that [Aart] had come in possession of over the years, with each salvaged part requiring the usual removal of old solder, before being mounted on prototype boards. The resulting design uses the 1 Hz time signal from a Hörz DCF77 master clock which he set up to drive a clock network in his house, as he describes in a forum post at Circuits Online (also in Dutch).

The digital pulses from this time signal are used by the relay network to create the minutes and hours count, which are read out via a resistor ladder made using 0.1% resistors that drive two analog meters, one for the minutes and the other for the hours.

Sadly, [Aart] did not draw up a schematic yet, and there are a few issues he would like to resolve regarding the meter indicators that will be put in front of the analog dials. These currently have weird transitions between sections on the hour side, and the 59 – 00 transition on the minute dial happens in the middle of the scale. But as [Aart] says, this gives the meter its own character, which is an assessment that is hard to argue with.

Thanks to [Lucas] for the tip.

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Hackaday Links: November 12, 2023

November 12, 2023 by 11 Comments

Somebody must really have it in for Cruise, because the bad press just keeps piling up for the robo-taxi company. We’ve highlighted many of the company’s woes in this space, from unscheduled rendezvous with various vehicles to random acts of vandalism and stupid AI pranks. The hits kept coming as California regulators pulled the plug on testing, which finally convinced parent company General Motors to put a halt to the whole Cruise testing program nationwide. You’d think that would be enough, but no — now we learn that Cruise cars had a problem recognizing children, to the point that there was concern that one of their autonomous cars could clobber a kid under the right conditions. The fact that they apparently knew this and kept sending cars out for IRL testing is a pretty bad look, to say the least. Sadly but predictably, Cruise has announced layoffs, starting with the employees who supported the now-mothballed robo-taxi fleet, including those who had the unenviable job of cleaning the cars after, err, being enjoyed by customers. It seems a bit wrongheaded to sack people who had no hand in engineering the cars, but then again, there seems to be a lot of wrongheadedness to go around.

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Relay Logic Nixie Tube Clock Checks All The Boxes

August 9, 2021 by 5 Comments

There are a few words in the electrical engineering lexicon that will perk any hardware hacker’s ears. The first of course is “Nixie tubes” with their warm cold war era ambiance and nostalgia inducing aura. A close second is “relay logic”. Between their place in computing and telecom history and the way a symphony of click and clatter can make a geek’s heart go pitter patter, most of us just love a good relay hack. And then there’s the classic hacker project: A unique timepiece to adorn our lair and remind us when we’ve been working on our project just a little too long, if such a thing even exists.

With those things in mind, you can forgive us if we swooned ever so slightly when [Jon Stanley]’s Relay Logic Nixie Tube Clock came to us via the Tip Line. Adorned with its plethora of clicking relays and set aglow by four Nixie tubes, the Relay Logic Nixie Tube Clock checks all our boxes. 

[Jon] started the build with relay modules that mimic CD4000 series CMOS logic chips. When the prototype stage was complete, the circuit was recreated on a new board that mounts all 55 Omron relays on the same PCB. The result? A glorious Nixie tube clock that will strike envy into even the purest hacker’s heart. Make sure to watch the video after the break!

[Jon] has graciously documented the entire build and even makes various relay logic boards available for purchase if you’d like to embark on your own relay logic exploits . His site overflows with unique clock projects as well, so you can be sure we’ll be checking those out. 

If you feel inspired to build your own relay logic project, make sure you source genuine Omron relays, especially if your Relay Computer Masterpiece takes six years to build.

Thanks to [Daniel] for sending this our way. Got a cool project you’d like to share? Be sure to send it in via the Tip Line. 

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Circuit VR: Advanced Falstad Logic With Geniac

August 20, 2019 by 2 Comments

I find that if I’m trying to make a point with a student or a colleague about a circuit, sometimes the Falstad online simulator is worth a few thousand words. You can draw the circuit, play with the values, and even see the current flow in an intuitive way as well as make traditional measurements. The simulator not only handles analog but also digital circuits. At first glance, though, the digital functions appear limited, but if you dig deeper, there is a custom logic block that can really help. I dug into this — and into how switches work in the simulator — the other day in response to a Hackaday post. If you use Falstad, read on!

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