Shedding A Bit Of Light On Some Logic

When it comes to logic technologies, we like to think we’ve seen them all here at Hackaday. But our community never ceases to surprise us with its variety and ingenuity, so it should be a surprise that [Dr Cockroach] has delivered one we’ve not seen before. Light logic doesn’t use the conventional active devices you’d expect such as transistors, tubes, or even relays. Instead, it uses LEDs and CdS cells to make rudimentary switches. So far there is a NAND, a NOR, and a set-reset latch that appears in the video below the break, and it is not inconceivable that …read more

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Behind The Pin: Logic Level Outputs

There is one thing that unites almost every computer and logic circuit commonly used in the hardware hacking and experimentation arena. No matter what its age, speed, or internal configuration, electronics speak to the world through logic level I/O. A single conductor which is switched between voltage levels to denote a logic 1 or logic zero. This is an interface standard that has survived the decades from the earliest integrated circuit logic output of the 1960s to the latest microcontroller GPIO in 2018.

The effect of this tried and true arrangement is that we can take a 7400 series I/O …read more

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Glimmies, as logic

[Jacob Christ] writes in with a hack that’s going to be this summer’s fidget spinner. Why? The favourite toy of his youngster’s generation is a Glimmie. And while fidget spinners were useful for, well, spinning, the small animal-like Glimmie seems to have an unexpected property, they can function as logic gates.

They form an optical inverter, in their head is a phototransistor and in their belly an LED which goes on when the head is in the dark. He’s found through experimentation that they can be combined to form an AND gate, and thus a NAND gate with the addition …read more

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Cigar Box Synth is a Fun Time

It’s fair to say that the groovebox market has exploded. Store shelves are overflowing with the umpteenth releases from KORG’s Volca line and the latest Pocket Operators. These devices often feature a wide array of tones in an enticingly compact and attractive package, but is it possible to build something similar at home? As [lonesoulsurfer] relates, it certainly is.

The Cigar Box Synth is, well… a synth, built in a cigar box. Based upon a 555 & 556 timer, and a 4017 decade counter, it provides a wealth of beepy goodness all crammed into a neat wooden package. We dig …read more

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The One-Transistor Flip-Flop

A flip-flop is one of the most basic digital electronic circuits. It can most easily be built from just two transistors, although they can and have been built out of vacuum tubes, NAND and NOR gates, and Minecraft redstone. Conventional wisdom says you can’t build a flip-flop with just one transistor, but here we are. [roelh] has built a flip-flop circuit using only one transistor and some bizarre logic that’s been slowly developing over on hackaday.io.

[roelh]’s single transistor flip-flop is heavily inspired by a few of the strange logic projects we’ve seen over the years. The weirdest, by far, …read more

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An 8-Bit ALU, Entirely From NAND Gates

One of the things that every student of digital electronics learns, is that every single logic function can be made from a combination of NAND gates. But nobody is foolhardy enough to give it a try, after all that would require a truly huge number of gates!

Someone evidently forgot to tell [Notbookies], for he has made a complete 8-bit ALU using only 4011B quad NAND gates on a set of breadboards, and in doing so has created a minor masterpiece with his wiring. It’s inspired by a series of videos from [Ben Eater] describing the construction of a computer …read more

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Hackaday Links: December 17, 2017

Where do you go if you want crazy old electronic crap? If you’re thinking a ham swap meet is the best place, think again. [Fran] got the opportunity to clean out the storage closet for the physics department at the University of Pennsylvania. Oh, man is there some cool stuff here. This room was filled to the brim with old databooks and development boards, and a sample kit for the unobtanium Nimo tube.

The Gigatron is a Hackaday Prize entry to build a multi-Megahertz computer with a color display out of TTL logic. Now, all this work is finally paying …read more

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