This portable sample player packs quite a punch. [Lee] wanted a nice portable way to take his samples with him, but refused to water-down the features just because it is portable. He set of goal of playing between 3-8 simultaneous notes from a large assortment of stored samples.
Sample space was the first design consideration, and it’s hard to beat the price per megabyte of an SD card. After some calculations he concluded that it is possible to pull these samples off the card quickly enough to achieve his simultaneous note goal at CD quality frequencies, but only if there is little or no latency when reading from the card. This means [Lee] needed a fast processor so he chose the LPC1769 which is an ARM Cortex-M3 processor which can run at 120 MHz.
The project box includes room for a volume knob to control the output from the in-build headphone amplifier. There’s also a rotary encoder for selecting sample sets. But we’re a bit confused on this part as the device is MIDI controlled. [Lee] is the creator of the electronic Moolodeon, which itself has MIDI out and will be used as a controller for this project.
Here’s a floppy drive which is being used as an audio sampler. At first glance we thought this was another offering which drives the stepper motor at a specific frequency to generate that characteristic sound at a target pitch. But that’s not what’s happening at all. The floppy is actually being used as a storage device (go figure).
From what we can tell, it’s being used almost like an 8-track tape. A PWM signal is stored on one circular slice of the disk, then the head can be moved back to that same “track” to play back the wave form. The head doesn’t move during playback, but just keeps reading the same track of bits. To the right you can see an Arduino board. This allows for MIDI control of the track selection. [Alexis] shows off some keyboard control in the video after the break. There’s a buffer chip on the breadboard which allows the audio output to be quickly switched off as the floppy drive head is moved. This keeps garbage out of the sound until the new track can be read.
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[Michael] is a huge fan of old media formats. There’s something special about quarter-inch thick 78s, fragile blue cylinders holding music, and thin strips of mylar that preserve the human voice. He’s had an idea for a tape-based instrument for a while, and now that the Magnetotron is complete, we’re in awe of this glass harmonica and Mellotron mashup.
The Magnetotron is a large rotating cylinder that has dozens of strips of audio tape attached to it. The cylinder rotates with the help of a small motor. As the strips of tape rotate in front of him, [Michael] presses two tape heads up to the instrument, making some sort of sound.
Each strip of tape contains a recording of one note, like the venerable Mellotron. Instead of physical keys, the Magnetotron is played in a much more tactile fashion like the glass harmonica. The output of the Magnetotron is interesting with a whole bunch of wow and flutter. Check out the demo of [Michael] playing his instrument at NIME in Brooklyn after the break.
Continue reading “Magnetotron is an armonica mellotron mashup”
[Roberto Barrios] has a Korg Triton sampling keyboard which he enjoys very much, but has grown tired of using media of yesteryear to store his work. He had the option of floppy disk or Jazz drive and for a time he was using a floppy-to-USB emulator, but the keyboard still insisted on a 1.44 Mb storage limit using that method. He decided to crack open the case and add his own CF reader.
It should be noted that this hack could have been avoided by using the 25-pin connector on the back of the keyboard. He didn’t want to have external hardware, which is understandable if you’re gigging–it’s just more equipment to keep track of. His solution uses the floppy disk drive opening to mount the card reader. His electrical connections are made with a ribbon cable. He cut off one end, and soldered the individual wires to the contacts on the motherboard. The reader is seen as a SCSI drive by the Korg firmware thanks to a SCSI-to-IDE adapter, so the storage limitation is based quite fittingly on the size of the CF card used.
Look at that cable management. You’d think it came straight from the factory like this!
Where’s the Party At is an open source bendable 8-bit sampler kit created by [Todd Bailey]. The initial design started about a year ago when he was instructing circuit benders how to transition to circuit design. He designed the kit to show how simply you could build a sampler. It demonstrates both clear analog and digital design. It’s meant to be a unique instrument though and features a lot of glitchy/quirky characteristics while being fairly reliable. You can read more about the device on his site. It has comprehensive parts and assembly manuals available and the kit is $75.
[via Create Digital Music]