Reed Organ MIDI Conversion Tickles All 88 Keys

September 13, 2017 by Dan Maloney 11 Comments

What did you do in high school? Chances are it wasn’t anywhere near as cool as turning a reed organ into a MIDI device. And even if you managed to pull something like that off, did you do it by mechanically controlling all 88 keys? Didn’t think so.

A reed organ is a keyboard instrument that channels moving air over sets of tuned brass reeds to produce notes. Most are fairly complex affairs with multiple keyboards and extra controls, but the one that [Willem Hillier] scored for free looks almost the same as a piano. Even with the free instrument [Willem] is about $500 into this project. Almost half of the budget went to the solenoids and driver MOSFETs — there’s a solenoid for each key, after all. And each one required minor surgery to reduce the clicking and clacking sounds that don’t exactly contribute to the musical experience. [Willem] designed custom driver boards for the MOSFETs with 16 channels per board, and added in a couple of power supplies to feed all those hungry solenoids and the three Arduinos needed to run the show. The video below shows the organ being stress-tested with the peppy “Flight of the Bumblebee”; there’s nothing wrong with a little showing off.

[Willem]’s build adds yet another instrument to the MIDI fold. We’ve covered plenty before, from accordions to harmonicas and even a really annoying siren.

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Theremin In Detail

September 9, 2017 by Al Williams 4 Comments

[Keystone Science] recently posted a video about building a theremin — you know, the instrument that makes those strange whistles when you move your hands around it. The circuit is pretty simple (and borrowed) but we liked the way the video explains the theory and even dives into some of the math behind resonant frequencies.

The circuit uses two FETs for the oscillators. An LM386 amplifier (a Hackaday favorite) drives a speaker so you can use the instrument without external equipment. The initial build is on a breadboard, but the final build is on a PCB and has a case.

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Raspberry Pi AI Plays Piano

September 6, 2017 by Al Williams 7 Comments

[Zack] watched a video of [Dan Tepfer] using a computer with a MIDI keyboard to do some automatic fills when playing. He decided he wanted to do better and set out to create an AI that would learn–in real time–how to insert style-appropriate tunes in the gap between the human performance.

If you want the code, you can find it on GitHub. However, the really interesting part is the log of his experiences, successes, and failures. If you want to see the result, check out the video below where he riffs for about 30 seconds and the AI starts taking over for the melody when the performer stops.

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Teenage Engineering The Raspberry Pi

September 5, 2017 by Brian Benchoff 22 Comments

The Teenage Engineering OP-1 is a tiny, portable synthesizer loaded up with 4-track recording, a sampler, sequencers, and a quite good synthesis engine. It also fits in your pocket and looks like a calculator built in West Germany. As you would expect with a synth/sampler/sequencer, you can save sounds, tracks, and other creations to a computer. [Doug] thought if you can connect it to a laptop, you can also connect it to a Raspberry Pi. He created an all-in-one storage solution for the OP-1 using only a Pi and a small character LCD.

The process of connecting the Pi to the OP-1 is pretty simple. First, plug a USB cable into the OP-1 and the Pi. Then, place the OP-1 into Disk Mode, the synth’s method of transferring files between itself and a computer. The Pi then synchronizes, changes the color of its character display from red to green, and becomes a web server available over WiFi where all the files can be accessed.

This is the bare minimum tech required to get files into and off of the OP-1. All you need is a bit of power and a USB connection, and all the files on the OP-1 can be backed up, transferred, or replaced without any other futzing around. It’s perfect for the minimalist OP-1, and a great example of how handy a WiFi enabled Pi can be.

Thanks [Pator] for sending this one in.

Tough Pi-ano Can Take A Punch

September 4, 2017 by Brian McEvoy 14 Comments

There will be no delicate solos for [24 Hour Engineer’s] Tough Pi-ano. It was built to soak punishment from aggressive youngsters in musical therapy, specifically those on the autism spectrum and those with Down’s syndrome. The Tough Pi-ano will be bolted to a wall with heavy-duty shelf brackets so it can’t fall on anyone. The keyboard is covered in plastic and it doesn’t have any exposed metal so there will be no splinters.

[24 Hour Engineer] made a short video demonstration and if you listen closely, he has a pun in all but one sentence. We love that kind of easter egg in YouTube videos. Check it out after the break.

Inside the 48-key instrument are four Raspberry Pi Zeros where each Pi controls one octave. The redundancy ensures that a hardware failure only drops out a single octave and the kids can keep playing until replacement parts arrive. Each Pi has identical programming and a thumbwheel switch tells it which octave it will be emulating.

Programming was done with Python and Pygame and all the inputs are run to a homemade “hat” where the wires are soldered. Pygame’s sole responsibility is to monitor the GPIO and then play the appropriate note when a button is pressed, slapped, punched or sat upon.

Similar in name, the Touch Piano has no moving parts or perhaps you would rather use your Raspberry Pi in an upright piano.

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Can You Visualise A Sega Cart From 2017?

August 31, 2017 by Lewin Day 13 Comments

The Sega Genesis, or Mega Drive if you’re not from North America, isn’t exactly this summer’s hottest new console, but it still has a huge following 29 years after launch. Fans range from retro Sonic enthusiasts to hardcore chiptune composers, and this year, Catskull Electronics is releasing a Genesis compilation album on a cartridge with a rather special feature.

The cartridge sports an 8×8 LED matrix, which acts as a visualiser for the audio coming out of the console. They’re controlled with a combination of data and address lines with some buffers and 74-series glue logic to make it all work together. Special attention was paid to make sure the LED matrix doesn’t just respond to all activity on the bus, though it would perhaps be cool to see some blinkenlights on a 90s console one day.

Each row of LEDs is attached to an address line, and each column to a data line. It’s a fairly basic multiplexing setup which sees each LED only actually lit for a fraction of a second, but sweeping the display at speed creates a lasting display. The image data is stored as an 8×8 sprite in the system RAM, and updated with the sound level of each channel from the Genesis’s audio subsystem.

The team are looking to release the ROM code in future to inspire copycat designs, which has the potential to spawn even more Genesis cart releases in future. We look forward to seeing what else the community comes up with. And if you’re a die-hard Genesis fan, there are other ways to listen to those classic tunes too.

Portable SNES Chiptune Player

August 30, 2017 by Lewin Day 8 Comments

Chiptunes are the fantastic, bleeping musical renditions of the soundchips of retro consoles past. Performers of the art overwhelmingly favour the various flavours of Game Boy, though there are those who work with such varied machines as the Commodore 64, Sega Genesis, and the Nintendo Entertainment System. A little more off the beaten track in the chiptune scene is the Super Nintendo, but [kevtris] has struck out and built a chiptune player for SNES-based music.

The heavy lifting is handled by an FPGA, which emulates the SNES’s S-SMP sound processor, and handles loading the music from the SPC-format files. Being chiptunes, these files store both the instrument data as well as the note data for the music. Audio output is clean and crisp, as heard in the test video.

The laser cut case lends the device a great aesthetic.

Case design is where this project really shines. Laser cut clear acrylic is combined with a bright LCD character display and some LEDs which create an effect not unlike a glowing magical block from your 90s platformer of choice. It’s combined with some slick capacitive buttons that avoid the need to drill holes for bulky traditional buttons. [kevtris] goes through the case design, showing how it all fits together with a combination of screws and standoffs. Being built out of a series of essentially 2D slices, the case is stacked up one layer at a time.

What really stands out about this project is the fit and finish. There’s plenty of microcontroller and FPGA projects out there that can hum out a tune, but the attention to detail paid to the case design and the neatly laid out PCB really add polish to a project like this. For a different take, why not check out this chiptune player built around a Raspberry Pi?

[Thanks Morris!]