MP3 player design from Dooba.io:
Based on the ioNode, Aecho and Nomad modules, the Shiva allows browsing & playing MP3 files stored on any FAT-formatted MicroSD card with audio quality up to 128Kbps.
The actual Shiva board itself is quite simple, featuring an MCP23008 from Microchip for reading the 7 buttons, a DM3D-SF MicroSD card socket from Hirose and a 128×64 OLED display from Adafruit.
To keep everything neatly together I needed an enclosure. Being lucky enough to own a half-decent 3D printer I decided to keep things minimal but functional. Who needs glue and screws when you can go for a press-fit case?
The code for the Shiva MP3 player is available in the Dooba Firmware SDK under /src/shiva. Schematic and board are available in the Dooba Hardware collection.
[Ross Fish], [Darcy Neal], [Ben Davis], and [Paul Stoffregen] created “the Monolith”, an interactive synth sculpture designed to showcase capabilities of the Teensy 3.6 microcontroller. The Monolith consists of a clear acrylic box covered in LED-lit arcade buttons. The forty buttons in front serve as an 8-step sequencer with five different voices, while touch sensors on the left…
via The Monolith Brings the Boom to Maker Faire — Hackaday
General Instrument’s AY-3-8910 is a chip associated with video game music and is became popular with arcade games and pinball machines. The chip tunes produced by this IC are iconic and are reminiscent of a great era for electronics. [Deater] has done an amazing job at creating a harmony between the old and new with his Raspberry…
via Multifunction Raspberry Pi Chiptune Player — Hackaday
Teensy creator Paul Stoffregen has shared a new project on OSH Park:
The Monolith Synth Project needed to use a large number of these LED lit arcade buttons.
Dimming of the LEDs was required. Initially I considered using this Adafruit 16 Channel PWM board. But the LEDs in these buttons have integrated resistors which require 12 volts, so 16 transistor circuits and another board for reading the switches would have also been needed.
It uses the same PCA9685 chip for 12 bit PWM control on every LED, with mosfet drivers to handle 12V outputs, and also a MCP23017 chip to read the buttons. Every button has a discrete 1K pullup resistor (rather than using the higher impedance on-chip pullups) to help with use in the same cable bundles cross coupling to 12V PWM signals.
Four of these boards where used in the Monolith Synth project:
The project is featured in this Tested video:
From Brian Benchoff on Hackaday:
Before there were samplers, romplers, Skrillex, FM synths, and all the other sounds that don’t fit into the trailer for the new Blade Runner movie, electronic music was simple. Voltage controlled oscillators, voltage controlled filters, and CV keyboards ruled the roost. We’ve gone over a lot of voltage controlled synths, but [Tommy] took it to the next level. He designed a small, minimum viable synth based around the VCO in an old 4046 PLL chip
The circuit for this synth is built in two halves. The biggest, and what probably took the most time designing, is the key bed. This is a one-octave keyboard that’s completely 3D printed. We’ve seen something like this before in one of the projects from the SupplyFrame Design Lab residents, though while that keyboard worked it was necessary for [Tim], the creator of that project, to find a company that could make custom key beds for him.
Read more on the F0 on Tommy’s blog:
Paul Stoffregen posted an update in his Teensy Audio Library on Hackaday.io:
Some projects need a lot of audio I/O. Maybe you’re doing positional audio sound effects (using the 8-tap delay effect) where ordinary stereo or even 5 channel “surround” isn’t enough? Maybe you’re making the ultimate Eurorack synthesizer module? Or you just want a lot of signals, because you can!
Here’s a board for the Cirrus Logic CS42448 chip, which provides 6 inputs and 8 outputs. All are high quality audio, and all work simultaneously.
PaulStoffregen has shared the board on OSH Park:
Paul Stoffregen has shared this Teensy audio shield:
PT8211 is an inexpensive 16 bit stereo DAC.
This small breakout board connects the PT8211 to Teensy 3.2, Teensy 3.5 or Teensy 3.6.