Category Archives: relay

Knitting ALUs (and Flipdots)

[Irene Posch] is big into knitted circuits. And while most of the textile circuits that we’ve seen are content with simply conducting enough juice to light an LED, [Irene]’s sights are set on knittable arithmetic logic units (ALUs). While we usually think of transistors as the fundamental building-blocks of logic circuits, [Irene] has developed what is essentially a knit relay. Be sure to watch the video after the break to see it in construction and in action.

The basic construction is a coil of conductive thread that forms an electromagnet, and a magnetic bead suspended on an axle so that …read more

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Posted in ALU, computer, electromagnet, fabric, flipdot, hardware, relay, textile | Leave a comment

Single Board Relay Computer

We all know you can build a computer out of relays, and if you’re a regular reader of Hackaday, you’ve probably seen a few. Actually designing and fabricating a computer built around relays is another thing entirely, and an accomplishment that will put you right up there with the hardware greats.

The newest inductee of the DIY microcomputer hall of fame is [Jhallen]. He’s built a microcomputer ‘trainer’ out of relays. It’s got more click and clack than the Tappet family, and is a work of art rendered in DPDT relays.

The biggest consideration in designing a relay computer is …read more

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Posted in hardware, relay, relay computer, Single board relay computer, Tindie | Leave a comment

Relay Computer: You Can Hear It Think

Modern digital computers have complex instruction sets that runs on state-of-the-art ALUs which in turn are a consequence of miniaturized logic gates that are built with tiny transistors. These tiny transistors are essentially switches. You could imagine replacing with electromagnetic relays, and get what is called a relay computer. If you can imagine it, someone’s done it. In this case, [jhallenworld].

The Z3 was the first working programmable, fully automatic digital computer designed by Konrad Zuse. The board employs modern semiconductor devices such as memory and microcontrollers, however, the CPU is all relays. A hexadecimal keyboard allows for program entry …read more

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Posted in classic hacks, computer, Computer Hacks, cpu, discrete, relay, relay computer | Leave a comment

Have Alexa Open Your Garage Door

[yoyotechKnows] built an Alexa-controlled garage door opener after his Liftmaster stopped working. Now all he has to do is holler at his mobile phone and he can raise and lower his garage doors at will.

His project is based around a Photon WiFi kit, with a pair of LCC 120 digital relays triggering the two doors, reed switches, and a serial-equipped LCD to display door status, with Alexa, IFTTT, and OpenHab to process the commands. You can find his code in the project writeup.

Currently he has a LCD display informing him of the status of each door, hot glued …read more

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Posted in alexa, garage door opener, home automation, home hacks, reed switch, relay | Leave a comment

Fight Mold and Mildew with an IoT Bathroom Fan

Delicious sheets of wallboard coated with yummy latex paints, all kept warm and moist by a daily deluge of showers and habitually forgetting to turn on the bathroom exhaust fan. You want mildew? Because that’s how you get mildew.

Fed up with the fuzzy little black spots on the ceiling, [Innovative Tom] decided to make bathroom ventilation a bit easier with this humidity-sensing IoT control for his bathroom exhaust fan. Truthfully, his build accomplishes little more than a $15 timer switch for the fan would, with one critical difference — it turns the fan on automatically when the DHT11 sensor …read more

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Posted in bathroom, blynk, dht11, home hacks, humidity, IoT, relay, shield, Wemos | Leave a comment

Spoiler Alert! Repairing A Race Car Can Get Complicated, Fast.

[Big Fish Motorsports] has a vehicle with an adjustable rear spoiler system that broke in the lead up to a big race. The original builder had since gone AWOL so the considerable talents of [Quinn Dunki] were brought to bear in getting it working again.

Cracking open the black control box of mystery revealed an Arduino, a ProtoShield and the first major road block: the Arduino remained stubbornly incommunicado despite several different methods of trying to read the source code. Turns out the Arduino’s ATMega324 was configured to be unreadable or simply fried, but an ATMega128 [Quinn] had proved to …read more

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Posted in adjustable, Android Hacks, atmega, automotive, car, car hacks, ProtoShield, RACE, relay, Spoiler | Leave a comment

iPad, not Flux Capacitor, Brings DeLorean Back to the Future

Add a flux capacitor and a Mr. Fusion to a DeLorean and it becomes a time machine. But without those, a DeLorean is just a car. A 35-year old car at that, and thus lacking even the most basic modern amenities. No GPS, no Bluetooth — not even remote locks for the gullwing doors!

To fix that, [TheKingofDub] decided to deck his DeLorean out with an iPad dash computer that upgrades the cockpit experience, and we have to say we’re impressed by the results. Luckily, the space occupied by the original stereo and dash vents in the center console is …read more

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Posted in back to the future, backup camera, bluetooth, BttF, car hacks, dash computer, DeLorean, Flux Capacitor, gps, ipad, relay, transportation hacks | Leave a comment

Oscillating Fan Controller Used As Relay

The most brilliant hacks we see aren’t always the thousand-dollar, multi-year projects spanning every facet of engineering. Rather, the most ingenious projects are ones that take an everyday thing and use it in a simple but revolutionary way. By that measure, it’ll be hard to top [Robert]’s latest hack which uses the controller board from an everyday oscillating fan to build a three-way remote-controlled relay board.

Most oscillating fans have a speed selector switch. What that does might be somewhat different between different types of fan, but in general it will select either a smaller portion of the fan’s motor …read more

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Posted in board, control, fan, home hacks, oscillating, relay, switch | Leave a comment

Early Electromechanical Circuits

In the days before semiconductor diodes, transistors, or even vacuum tubes, mechanical means were used for doing many of the same things. But there’s still plenty of fun to be had in using those mechanical means today, as [Manuel] did recently with his relay computer. This post is a walk through some circuits that used those mechanical solutions before the invention of the more electronic and less mechanical means came along.

Coherer Morse Code Receiver

The circuit shown below is a fun one, especially if you’ve played with crystal radios. It receives Morse code that’s transmitted as bursts of radio …read more

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Posted in Alexander Popov, coherer, Curated, decoherer, Featured, history, lightning detector, morse code, relay, siphon, solenoid, telegraph | Leave a comment

Relay Computing

Recently, [Manuel] did a post on making logic gates out of anything. He mentioned a site about relay logic. While it is true that you can build logic gates using switch logic (that is, two switches in series are an AND gate and two in parallel are an OR gate), it isn’t the only way. If you are wiring a large circuit, there’s some benefit to having regular modules. A lot of computers based on discrete switching elements worked this way: you had a PCB that contained some number of a basic gate (say, a two input NAND gate) and …read more

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Posted in Engineering, Hackaday Columns, logic, logic gates, misc hacks, mux, relay, relay computer, relays | Leave a comment