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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Ask Hackaday: Bringing Your Design to Market

While many of us have made and documented our open source projects, not many of us have tried to sell our design to the masses. [Scott] developed, marketed, and “bootstrapped” a cool looking MIDI controller. Now, before you get your jumpers in a bunch – the project is completely open source. [Scott] documented the entire process of not only the design, but the trials and tribulations of bringing it to market as well. Calculating costs, FCC testing and the many other challenges of bringing a consumer electronics device to market are all detailed in his blog. Join me while we look at the highs and lows of his interesting and eventually worthwhile journey.

Putting yourself into a game where orders are in the tens of thousands, with hundreds of thousands of dollars changing hands is not easy when you’re just a guy with an idea and a soldering iron. [Scott] was up for the challenge, however. He quickly realized that much of the margin is spent on advertising and to cover risk. On his last order, some of the paint was chipping off. He had to fix the paint and repackage everything – all at his cost.

He also talks about the learning process of product design along the way. His original idea was to make a volume controller, but couldn’t sell a single one. He was forced to redesign the software into the MIDI controller as it exists today. He tried to launch a Kickstarter, but was rejected. This turned out to be a good thing, however, because he would have wound up kickstarting a product that didn’t work.

For advertising, he relied on Google and made some extremely detailed tutorials for his product. Many of them can be used for other MIDI controllers, and often come up in Google searches. Smart. Very smart.

Be sure to check out the video below, where [Scott] gets into some capacitive touch design theory, and talks about how not to cut your final product in half while on the CNC.

Have any of you ever tried to mass produce and sell one of your designs? Let us know in the comments!

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Modular 555 Synth is Controlled by MIDI

[Atdiy and Whisker] aka [The Tymkrs] have created a  MIDI controlled 8 note modular synthesizer. (YouTube link). The project was designed to highlight some of the modules they have available at their Tindie Store. Essentially, the synthesizer is 8 classic Atari Punk Console (APC) tone generators. Each APC is made up of two 555 chips, rather than the 556 used in the original design. The APCs are tuned to a Pentatonic scale, with the 8 notes covering 1.5 octaves. [Whisker] added a single potentiometer which controls all 8 of the monostable oscillators at once. Tweaking this knob gives the synth that classic Atari Punk Console sound we’ve all come to know and love.

The 8 APC outputs are routed to once side of an AND gate. The other side of the AND gate is connected to a 74hc595 shift register. A Parallax Propeller processor converts MIDI note data into a serial stream that can be daisy chained across several ‘595 shift registers. The outputs of the 8 and gates are mixed to a single combined output, which goes out to [The Tymkrs] studio amplifier.

Like many [Tymkrs] videos, this one ends with a MIDI driven jam session, outlining how the circuit would sound in a song. Click past the break to see it all in action!

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Wireless Mic Helps Guitarist Rock Out Un-Tethered

Any guitarist knows what a tangled mess of cords can come out of a long jam session. One possible solution would be to get a wireless guitar system, however, such a setup can range in price from about 50 to several hundred dollars. That’s a big price to pay for not having to untangle some guitar cords.

[mattthegamer463] wanted a wireless setup but didn’t want to spend the cash on one. He’s a tinkerer and had a spare wireless microphone setup hanging around. So, he decided to try converting the wireless mic to work with his guitar.

Both microphones and guitar pickups work in similar manner. In a guitar pickup, the vibrating guitar string disturbs a magnetic field and induces a current in the pickup’s coil. That current is the guitar’s signal. Microphones are similar, air pressure waves vibrate a diaphragm or ribbon which then disturbs a magnetic field to create the signal. [mattthegamer463]  thought these principles were close enough for him to make quick work of the conversion.

First, the microphone was taken apart and the diaphragm module was removed, cutting the two wires that ran into the mic’s handle. A hole was then drilled into the wind screen so a 1/4″ jack could be installed. [mattthegamer463] states that it’s important to electrically isolate the jack from the wind screen or the signal and ground wires will short and the project won’t work. The two wires that were previously connected to the diaphragm module are then soldered to the newly added jack and the mic was screwed back together.

To use it, a patch cord is run from the guitar into the jack on the mic. The stock wireless receiver from the mic system is then plugged into the guitar amp. The modified ‘mic’ now transmits the guitar signals to the guitar amp! You may think it would be awkward to hold that mic while jamming. You’d be right if [mattthegamer463] didn’t come up with a nice looking aluminum and rubber belt clip.

Rocking a New Sound for Guitar

We’ve seen inventive sound hacking from [Jeremy Bell] before on Hackaday. You may remember reading a few months ago about how he invented a new way to produce that familiar effect DJs create when scratching records. By clipping samples from cassette tapes and stretching them across a set of short rails, he was able to refashion the audio pickup to glide over the tape at his fingertips. With a clothes pin wrapped in strips of foil teetering over a contact, he had a responsive tactile switch to aid in producing the cutting needed to carve out a beat.

Since then, [Jeremy] has been evolving this same switch concept and testing out new applications for it. The most recent of which he appropriately referrers to as the “Rocker”. With an electric guitar as a starting point, [Jeremy] uses a similar switching technique to bounce back and forth between two audio signals. The first of which being the sound produced in real-time by hammering on the frets of the guitar, and the second channel having a slight delay. By leveraging the glitchy effect created when switching between the two channels he is able to produce a sound all its own.

The prototype seen in his video is table-bound like the early versions of his Scrubboard, yet he’s able to play one-handed with the guitar and demo his device like a cake walk. It’d be fantastic to see this quirkiness and ingenuity taken to the level of his previous hack, leading to a stand-alone add-on for the guitar. Either way, this is yet another great example of sound play:

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Digitally Controlled Circuit Bending

Circuit bending doesn’t get a lot of respect around some parts of the Internet we frequent, but there is certainly an artistry to it. Case in point is the most incredible circuit bending we’ve ever seen. Yes, it’s soldering wires to seemingly random points on a PCB, but these bend points are digitally controlled, allowing a drum machine to transform between bent crunchiness and a classic 1980s drum machine with just a few presses of a touch screen controller.

All circuit bending must begin with an interesting piece of equipment and for this project, [Charles], the creator of this masterpiece of circuit bending, is using a Roland TR-626, a slightly more modern version of the TR-606, the percussive counterpart of the infamous TB-303. The circuit is bent in the classical fashion – tying signals on the PCB to ground, VCC, or other signals on the board. [Charles] then out does everyone else by connecting these wires to 384 analog switches controlled by an Arduino Mega. Also on the Arduino is a touch screen, and with a slick UI, this old drum machine can be bent digitally, no vast array of toggle switches required.

[Charles] has put up a few videos going over the construction, capabilities, and sound of this touch screen, circuit bent drum machine. It’s an amazing piece of work, and something that raises the bar for every circuit bending mod from this point on.

Thanks [oxygen_addiction] and [Kroaton] for sending this one in.

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