Logic Noise: The Switching Sequencer Has the Beat

Logic Noise is all about using logic circuits to make sounds. Preferably sound that will be enjoyable to hear and useful for making music. This week, we’ll be scratching the surface of one of my favorite chips to use and abuse for, well, nearly anything: the 4051 8-way analog switch. As the name suggests, you can hook up eight inputs and select one from among them to be connected up to the output. (Alternatively, you can send a single input to one of eight destinations, but we won’t be doing that here.)

Why is this cool? Well, imagine that you wanted to make our oscillator play eight notes. If you worked through our first installment, you built an abrasive-sounding but versatile oscillator. I had you tapping manually on eight different resistors or turning a potentiometer to eight different positions. This week, we’ll be letting the 4051 take over some of the controls, leaving us to do the more advanced knob twiddling.

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Logic Noise: 8-bits of Glorious Sounds

Logic Noise is all about using analog circuits to make sounds. Preferably sound that will be enjoyable to hear and useful for making music. Now, the difference between music, sound, and noise is certainly in the ear of the behearer, but you must admit that last installment’s simple square wave lacked a little something. (Although the sync oscillator circuit extension was kinda cool.)

This week, we’ll take our single wimpy square-wave oscillator and beef it up by adding a bunch of sub-octaves to the mix. And we’ll do it using a chip that’ll be really useful for us in the future as well: the 4040 binary counter chip.

Counters (binary or decimal) are going to be fertile ground for more musical noise experiments. Why so? Because octaves are just doublings or halvings of frequencies, and because a lot of rhythmic patterns have factors of two underlying them.  Just think about the most basic drum pattern you know: bass drum on the one, snare on one and three, and hi-hats on one, two, three, and four. Each different instrument fires off twice as frequently as the one before it.

But for now, enough blabber. We’ve got an oscillator to build.

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Clocked 8-Bit Random Pattern Generator For a CMOS Synth

A random noise generator is pretty handy when working with music, and building one using a micro-controller can be pretty trivial. So it’s nice when someone comes along and builds it from a few analog and digital parts. [acidbourbon] built his Clocked 8-BIT Random Pattern Generator for  CMOS Synth  inspired and motivated by the recent article Logic Noise: Sweet, Sweet Oscillator Sounds by [Elliot Williams]. It’s 8-bit output can be used as a random sequencer for DIY CMOS synths.
This pattern generator is suited to to be used in combination with a 4051 8-channel analog multiplexer. But it sounds quite interesting on it’s own (best enjoyed in stereo, check out the video after the break). After building some CMOS synth circuits, [acidbourbon] moved on to make some sequencers and multiplexers which then let him to devise this random pattern generator which could be gated using a clock signal.

The basic principle is straight forward – generate noise, amplify it, apply a clock to get the gated noise output. His design choices for the various sections are well explained, based on constraints that he had to work with. Everything needs to work at 5V, but his noise generator circuit requires 12V to work. He choose to use a charge pump to generate -5V, resulting in a 10V supply, which was barely enough, but worked. A boost regulator might probably have served better to generate 12V, but maybe he already had the ICL7660 charge pump IC lying around in his parts bin. The rest of the circuit uses standard CMOS/TTL devices, and [acidbourbon] provides all of the design files for what looks like a neat, single sided PCB that can easily be made using the toner-transfer method.

Video below.

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Hacklet #8: The Animals


This week on the Hacklet we’re looking at Hackaday.io projects that are all about animals! Hackers and makers are well-known animal lovers, in fact many a hacker can be found with a pet curled up at their feet, or on their keyboard!

catWater[Brian’s] cat Roger loves drinking from the bathtub faucet. Unfortunately Roger hasn’t learned how to operate the faucet himself, so it gets left on quite a bit. To keep Roger happy while saving water, [Brian] created the Snooty Cat Waterer. Cat’s still don’t have thumbs, so [Brian] turned to capacitive sensing in the form of a Microchip MTCH10 capacitive proximity sensor chip. Coupled with a home etched PC board, the waterer can detect a cat at 3 inches. A valve and water feed teed off the toilet provide the flow. The project is moving along well, though Roger has been slow to warm up to this new water source.


catWater2[Jsc] has the opposite problem. His cat has decided that bathtubs are the perfect litter boxes. [Jsc] is taking aim at this little problem with his Cat Dissuader. After a servo controlled squirt bottle proved too anemic for his needs, [Jsc] turned to the Super Soaker Hydrostorm. These electric water guns can be had for as little as $16 on sale. [JSC] didn’t want to permanently modify the gun, so he 3D printed a switchable battery pack.The replacement pack is actually powered by a simple wall wart. Power to the gun is controlled by an Arduino, which senses his cat with a passive infrared sensor. Since the dissuader was installed, [Jsc’s] cat has been a model citizen!


doggieBowlCat’s don’t get all the love though, plenty of engineers and hackers have dogs around the house. [Colin] loves his dog, but he and his family were forgetting to feed it. He created Feed the Dog to help the household keep its four-legged member from going hungry. [Colin] tried a microcontroller, but eventually settled on implementing the circuit with old-fashioned 4000 series CMOS logic chips. He used a 4060 (14-stage ripple counter w/ internal oscillator) as an 8 hour timer, and 4013 dual flip-flop. Operation of Feed the Dog is as simple as wagging your tail. Once the dog is feed, the human presses a button. A green “Just fed” LED will glow for 30 minutes, then go dark. After about 6 hours, a red LED turns on. After 8 hours, the red LED starts blinking, letting everyone know that it’s time to feed the dog.



[Steve] has outdoor pets. Chooks to be exact, or chickens for the non Australians out there. He loves watching his birds, especially Darth Vader, who is practicing to become a rooster. To keep track of the birds, he’s created What the Chook?, a sensor suite for the hen-house. He’s using a GCDuiNode with a number of sensors. Temperature, humidity, even a methane detector for when the bedding needs to be replaced. An OV528 JPEG camera allows [Steve] to get pictures of his flock. The entire project connects via WiFi. Steve hopes to power it from a couple of AA batteries. [Steve] also entered What the Chook? in The Hackaday Prize. If he wins, this will be the first case of flightless birds sending a human to space!



Hey – Did you know that Hackaday is building a Hackerspace in Pasadena California? We’re rounding up the local community while our space is being built out. Join us at a Happy Hour Show & Tell Meetup Event hosted by our own [Jasmine Brackett] August 18th! It’s an informal show and tell, so you don’t have to bring a hack to attend. If you’re local to Pasadena, come on down and say hello!






CMOS logic clock tracks 24-hour time

Here’s an IC logic project that displays 24-hour time. Planning was the name of the game for this project. [Mattosx] took the time to layout his design as a PCB in order to avoid the wiring nightmare when build with point-to-point connections.

Much of the complexity is caused by the display itself. Each of the six digits has its own binary-coded decimal chip and array of discrete resistors. Timekeeping is handled by six decade counters, two divider chips, one AND gate chip, and one OR gate chip. He chose a SOIC crystal oscillator chip as the clock signal. We’re more partial to the idea of using mains voltage as the clock signal.

[Mattosx] posted the board artwork if you’d like to etch your own 5″x8″ PCB. Just make sure you read through all of his notes as not all of the chips are oriented in the same direction.

[via Reddit]

16-bit HCMOS computer is a wire wrapping wonderland

The D16/M is a 16-bit computer built using HCMOS logic chips. It’s a thing of beauty from every angle thanks to the work [John Doran] put into the hobby project. But he didn’t just take pictures of the build and slap them on a webpage. He took the time to publish a remarkable volume of documents for the computer too!

The processor can execute a total of 73 instructions and offers a 100-pin bus for accessing main memory and peripherals. So far he has documented three different peripheral boards, each of which is pluggable thanks to an edge connector that accepts the board. The expansion boards are for system memory, serial communication port, and a clever four-position SD card interface for persistent storage.

Got a question about the system? He wrote a FAQ. Want to learn from his obvious mastery of wire-wrapping? He wrote a wire wrapping tips guide. Like we said, there’s a mountain of documentation and the links to it all are included in his main project page.

[Thanks Allen]

Make your own integrated circuits at home

The Nyan Cat you see above is only 600 micrometers from head to tail. To put that into perspective, that’s about 10 times the diameter of a human hair. Also, that Nyan is etched into 200 nanometer thick copper foil and is the work of the HomeCMOS team, who is developing a hobbyist-friendly process to make integrated circuits and MEMS devices at home.

The project is far from complete; HomeCMOS has yet to produce a working IC but a few experiments – getting wet etching down pat and even building an almost working quantum qbit – are remarkable given the small amount of equipment and tools involved.

The HomeCMOS team has yet to actually make an integrated circuit or MEMS device, [Jeri Ellsworth] has shown this is possible by making transistors and integrated circuits at home. While there won’t be chips with millions of transistors coming out of the HomeCMOS lab anytime soon, it’s more than possible to see a few small-scale integration-level tech such as a few logic gates or a regulator.