Logic Noise: Sawing Away with Analog Waveforms

Today we’ll take a journey into less noisy noise, and leave behind the comfortable digital world that we’ve been living in. The payoff? Smoother sounds, because today we start our trip into analog.

If you remember back to our first session when I was explaining how the basic oscillator loads and unloads a capacitor, triggering the output high or low when it crosses two different thresholds. At the time, we pointed out that there was a triangle waveform being generated, but that you’d have a hard time amplifying it without buffering. Today we buffer, and get that triangle wave out to our amplifiers.

triangle_square

But as long as we’re amplifying, we might as well overdrive the amps and head off to the land of distortion. We’ll do just that and build up a triangle-wave oscillator that can morph into a square wave, passing through a rounded-over kinda square wave along the way. The triangle sounds nice and mellow, and the square wave sounds bright and noisy. (You should be used to them by now…) And we get everything in between.

And while we’re at it, we might as well turn the triangle wave into a sawtooth for that nice buzzy-bass sound. Then we can turn the fat sawtooth into a much brighter sounding pulse wave, a near cousin of the square wave above.

What’s making all this work for us? Some dead-boring amplification with negative feedback, and the (mis-)use of a logic chip to get it. After the break I’ll introduce our Chip of the Day: the 4069UB.

If you somehow missed them, here are the first three installments of Logic Noise:

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Origami Busts a Move with Dancing Paper

Origami cranes are cool, but do you know what’s cooler? Origami cranes dancing to the beat. That’s the challenge [Basami Sentaku] took on when he created Dancing Paper (YouTube link). You might remember [Basami] from his 8 bit harmonica hack. In Dancing Paper, paper cranes seem to dance all on their own – even performing some crazy spinning moves. Of course, the “magic” is due to some carefully written code, and magnets, lots of magnets.

Using magnets to move objects from below isn’t a new concept. Many of us have seen the “ice skating pond” Christmas decoration which uses the same effect. Unlike the skating pond,Dancing Paper has moving parts (other than the cranes themselves). Under the plastic surface are a series of individually controlled electromagnets. Each of the supporting dancers has a line of four magnets, while the featured dancer in the center has a 5×5 matrix. The 41 electromagnets were wound around bolts with the help of a Tamiya motor and gearbox.

The actual dance moves are controlled by C code which appears to be running on an Atmel microcontroller. Of course a microcontroller wouldn’t be able to drive those big coils, so some beefy TO-220 case transistors were employed to switch the loads. The cranes themselves needed a bit of modification as well. Thin pieces of wire travel from the neodymium magnets on their feet up to the body of the crane. The wire provides just enough support to keep the paper from collapsing, while still being flexible enough to boogie down.

Click past the break to see Dancing Paper in action!

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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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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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Dial is a Simple and Effective Wireless Media Controller

[Patrick] was looking for an easier way to control music and movies on his computer from across the room. There is a huge amount of remote control products that could be purchased to do this, but as a hacker [Patrick] wanted to make something himself. He calls his creation, “Dial” and it’s a simple but elegant solution to the problem.

Dial looks like a small cylindrical container that sits on a flat surface. It’s actually split into a top and bottom cylinder. The bottom acts as a base and stays stationary while the top acts as a dial and a push button. The case was designed in SOLIDWORKS and printed on a 3D printer.

The Dial runs on an Arduino Pro mini with a Bluetooth module. The original prototype used Bluetooth 2.0 and required a recharge after about a day. The latest version uses the Bluetooth low energy spec and can reportedly last several weeks on a single charge. Once the LiPo battery dies, it can be recharged easily once plugged into a USB port.

The mechanical component of the dial is actually an off-the-shelf rotary encoder. The encoder included a built-in push button to make things easier. The firmware is able to detect rotation in either direction, a button press, a double press, and a press-and-hold. This gives five different possible functions.

[Patrick] wrote two pieces of software to handle interaction with the Dial. The first is a C program to deal with the Bluetooth communication. The second is actually a set of Apple scripts to actually handle interaction between the Dial and the various media programs on his computer. This allows the user to more easily write their own scripts for whatever software they want. While this may have read like a product review, the Dial is actually open source! Continue reading “Dial is a Simple and Effective Wireless Media Controller”

Organ Donor Gives Up a Leslie Speaker

It was about ten years ago that [Richard] received an old musical organ. Moving to a new house meant it would be cumbersome to move the organ with him, so he opted to harvest some interesting components instead. Specifically, he kept the Leslie speaker.

A Leslie speaker is a special kind of speaker mechanism that creates a tremolo effect as well as a vibrato effect. You can hear this effect in [Richard’s] video below. Simple effects like this would be easy to do on a computer nowadays, but that wasn’t the case several decades ago. Before digital electronics, musical effects were often performed by analog means. [Richard’s] Leslie speaker is a small speaker behind of a Styrofoam baffle. The baffle spins around the speaker which changes the reflection angle of the sound, producing the musical effect.

[Richard] tried hooking this speaker up to other musical instruments but found that turning off the electric motor created an audible pop over the speakers. To remedy this, he build a simple “snubber” circuit. The circuit is just a simple 240 ohm resister and a 0.05 uF capacitor. These components give the transients a path to ground, preventing the pops and clicks when the motor is powered up. Now [Richard] can use this classic piece of audio equipment for newer projects. Continue reading “Organ Donor Gives Up a Leslie Speaker”