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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Digital to Analog to Digital to Analog to Digital Conversion

[Andy] had the idea of turning a mixing desk into a MIDI controller. At first glance, this idea seems extremely practical – mixers are a great way to get a lot of dials and faders in a cheap, compact, and robust enclosure. Exactly how you turn a mixer into a MIDI device is what’s important. This build might not be the most efficient, but it does have the best name ever: digital to analog to digital to analog to digital conversion.

The process starts by generating a sine wave on an Arduino with some direct digital synthesis. A 480 Hz square wave is generated on an ATTiny85. Both of these signals are then fed into a 74LS08 AND gate. According to the schematic [Andy] posted, these signals are going into two different gates, with the other input of the gate pulled high. The output of the gate is then sent through a pair of resistors and combined to the ‘audio out’ signal. [Andy] says this is ‘spine-crawling’ for people who do this professionally. If anyone knows what this part of the circuit actually does, please leave a note in the comments.

The signal from the AND gates is then fed into the mixer and sent out to the analog input of another Arduino. This Arduino converts the audio coming out of the mixer to frequencies using a Fast Hartley Transform. With a binary representation of what’s happening inside the mixer, [Andy] has something that can be converted into MIDI.

[Andy] put up a demo of this circuit working. He’s connected the MIDI out to Abelton and can modify MIDI parameters using an audio mixer. Video of that below if you’re still trying to wrap your head around this one.

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Making a Player Piano Talk MIDI

[Ramon] was always fascinated with pianos, and when he came across a few player piano rolls in an antique shop, a small kernel of a project idea was formed. He wondered if anyone had ever tried to convert a player piano into a full MIDI instrument, with a computer tickling the ivories with a few commands. This led to one of the best builds we’ve ever seen: a player piano connected to a computer.

[Ramon] found an old piano in Craigslist for a few hundred dollars, and once it made its way into the workshop the teardown began. Player pianos work via a vacuum, where air is sucked through a few pin points in a piano roll with a bellows. A series of pipes leading to each key translate these small holes into notes. Replicating this system for a MIDI device would be impossible, but there are a few companies that make electronic adapters for player pianos. All [Ramon] would have to do is replicate that.

The lead pipes were torn out and replaced with 88 separate solenoid valves. These valves are controlled via a shift register, and the shift registers controlled by an ATMega. There’s an astonishing amount of electronic and mechanical work invested in this build, and the finished product shows that.

As if turning an ancient player piano into something that can understand and play MIDI music wasn’t enough, [Ramon] decided to add a few visuals to the mix. He found a display with a ratio of 16:4.5 – yes, half as tall as 16:9 – and turned the front of the piano into a giant display. The ten different styles of visualization were whipped up in Processing.


The piano has so far been shown at an interactive art exhibit in Oakland, and hopefully it’ll make it to one of the Maker Faires next year. There are also plans to have this piano output MIDI with a key scanner underneath all the keys. Very impressive work.

Video below.

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Sheet Music to MIDI Converter

Learning to read sheet music is a challenge for new musicians, so a group of Cornell students decided to make a robot do it instead. For their final project, they built a robotic sheet music reader (link warning: this page seems to automatically start a .mov file download when loaded).

As an input, the robot takes a piano roll. This is a long strip of paper with music printed on it, which can easily be fed through the reader. A rotational servo keeps the strip feeding at a constant speed, and passes it through the reader.

The reader is based on a Melexis MLX75306 linear optical array. This IC is a 142 x 1 array of photodiodes, which is designed for fuel quality sensing in cars. In this project, it’s been repurposed as a camera to read the music as it passes by. An array of LEDs illuminates the piano roll, providing a more accurate reading.

The components are connected to an Atmel ATmega1284P, which does all the required control and processing. It creates a MIDI output of the piano roll, which can be connected to any hardware or software synthesizer.

MIDI Keyboard with Frickin’ Laser Keys

MIDI instruments are cool, but they’re not laser cool. That is, unless you’ve added lasers to your MIDI instrument like [Lasse].

[Lasse] started out with an old MIDI keyboard. The plan was to recycle an older keyboard rather than have to purchase something new. In this case, the team used an ESi Keycontrol 49. They keyboard was torn apart to get to the creamy center circuit boards. [Lasse] says that most MIDI keyboards come withe a MIDI controller board and the actual key control board.

Once the key controller board was identified, [Lasse] needed to figure out how to actually trigger the keys without the physical keyboard in place. He did this by shorting out different pads while the keyboard was hooked up to the computer. If he hit the correct pads, a note would play. Simple, but effective.

The housing for the project is made out of wood. Holes were drilled in one piece to mount 12 laser diodes. That number is not arbitrary. Those familiar with music theory will know that there are 12 notes in an octave. The lasers were powered via the 5V source from USB. The lasers were then aimed at another piece of wood.

Holes were drilled in this second piece wherever the lasers hit. Simple photo resistors were mounted here. The only other components needed for each laser sensor were a resistor and a transistor. This simple discreet circuit is enough to simulate a key press when the laser beam is broken. No programming or microcontrollers required. Check out the demonstration video below to see how it works. Continue reading “MIDI Keyboard with Frickin’ Laser Keys”

Using MIDI and Magnets to Produce Tones with Tines

Normally you’d expect the sound of a pipe organ to come from something gigantic. [Matthew Steinke] managed to squeeze all of that rich melodic depth into an acoustic device the size of a toaster (YouTube link) which uses electromagnetism to create its familiar sound.

[Matthew ’s] instrument has a series of thin vertical tines, each coupled with a small MIDI controlled electromagnet. As the magnet pulses with modulation at a specific frequency, the pull and release of the tine causes it to resonate continuously with a particular tone. The Tine Organ is capable of producing 20 chromatic notes in full polyphony starting in middle C and can be used as an attachment to a standard keyboard or a synthesizer app on a smart phone. The classic style body of the instrument is made out of mahogany and babinga and houses the soundboard as well as the mini microcontroller responsible for receiving the MIDI and regulating the software oscillators sending voltage to the magnets.

[Matthew’s] creation is as interesting to look at as it is to listen to, so I’d recommend checking out the video below to hear the awesome sound it produces:

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