I/O Expander for LED Arcade Buttons

May 30, 2017May 26, 2017 fustiniAudio, LED, Maker Faire, mfba17, music, synthLeave a comment

Teensy creator Paul Stoffregen has shared a new project on OSH Park:

I/O Expander for LED Arcade Buttons

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.

Monolith Synth

Four of these boards where used in the Monolith Synth project:

The project is featured in this Tested video:

3D Printing A Synthesizer

May 13, 2017May 12, 2017 fustini3d printing, 4046, Audio, hackaday, music, synth, SynthesizerLeave a comment

From Brian Benchoff on Hackaday:

3D Printing A Synthesizer

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

http://blog.tommy.sh/posts/hello-f0

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.

Hello, F0

Say hello to the F0: a minimalist, analog, square wave synthesizer.

Teensy: TDM Support For Many-Channel Audio I/O

May 1, 2017April 24, 2017 fustiniarduino, ARM, Audio, Cirrus Logic, microcontroller, TDM, teensyLeave a comment

Paul Stoffregen posted an update in his Teensy Audio Library on Hackaday.io:

TDM Support, For Many-Channel Audio I/O

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:

CS42448 Audio, 6 Inputs, 8 Outputs

PT8211 Audio Shield for Teensy

April 25, 2017April 20, 2017 fustiniARM, Audio, DAC, microcontroller, teensyLeave a comment

Paul Stoffregen has shared this Teensy audio shield:

PT8211 Audio Shield for Teensy

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.

Build a Synthesizer with Darcy Neal in Chicago

April 7, 2017April 5, 2017 fustinianalog, Audio, Chicago, fritzing, hackerspace, kicad, music, synth, Synthesizer, workshopLeave a comment

Darcy Neal will lead a workshop in Chicago on building your own synthesizer:

https://www.meetup.com/Solder-Stitch-And-Code/events/238959615/

We’ll learn about some of the building blocks of creating a synthesizer using the 4046 VCO and the classic 40106 CMOS ICs. The 4046 is a well documented and powerful IC that can be turned into a modular synth voice with just a few added components. Participants will learn to solder together their own prototyping PCB, build a circuit on a breadboard from a schematic, experiment with sensors, and learn the basics about how to produce custom circuit boards using design software like Kicad and Fritzing. No experience is necessary, but basic electronic knowledge or a strong interest in synths will be helpful.

SoundBeacon

April 3, 2017April 3, 2017 fustiniaccessibility, assistive technology, Audio, BLE, Bluetooth, ibeacon, wirelessLeave a comment

Patrick Van Oosterwijck created an audio BLE beacon that can be activated by the vision impaired to find exact locations of doorways, bus stops, crosswalks, and more:

SoundBeacon

The idea is that a blind person uses a navigation app, and can query to see “what is around”. In the list of beacons that are around, they can tap the one they want to know the location of and it will start to produce an audible signal for a short time.

https://hackaday.io/project/15595-soundbeacon

The BLE module is configured as an iBeacon and allows connections. It has a battery service and an “Immediate Alert” (AKA “Find me”) service.

Patrick used the following to build the prototype:

A 550 mAh 3.2 V LiFePO4 cell
A #LiFePO4wered/Solar1 prototype to charge the battery
A 5.5V, 0.6W monocrystalline solar cell
A Silicon Labs (formerly BlueGiga) BLE113 module
A beeper that works very badly (better solution needed)
And a IP65 enclosure

xorbit has shared the booster for loud piezo beeper on OSH Park:

PiezoBoost

Musical Toothbrush by Joe Grand

April 1, 2017March 31, 2017 fustiniatmel, attiny, attiny85, Audio, avr, microcontrollerLeave a comment

Hackaday wrote about a nifty hack by Joe Grand:

[Joe Grand’s] Toothbrush Plays Music That Doesn’t Suck

It’s not too exciting that [Joe Grand] has a toothbrush that plays music inside your head. That’s actually a trick that the manufacturer pulled off. It’s that [Joe] gave his toothbrush an SD card slot for music that doesn’t suck. The victim donor hardware for this project is a toothbrush meant for kids called Tooth Tunes.…

Joe published full documentation for the project on his website:

The PCB is shared on OSH Park:

Tooth Tunes Hack

Joe describes the project in this video:

Hear the toothbrush in action:

XMOS-based USB to I2S bridge

March 3, 2017March 2, 2017 fustiniAudio, DAC, Headphones, hifi, i2s, usb, xmosLeave a comment

An update from the USB DAC + Headphone Amp project by Yin Zhong (summivox):

USB Interface

Months into the project and I was still amazed at the lack of availability of a class of ASICs: USB-I²S bridges. Well I just lied — if you are fine with USB 1.1 and USB Audio Class (UAC) 1.0, which severely limits your (bit depth × resolution × channel count)

So I kept looking for ASICs, and I found one that is close enough: XMOS XHRA-2HPA. It even comes with a reference design that does exactly what I want!

summivox has shared the board on OSH Park:

20161229-1609 headphone-USB-v2.0.zip

Making a USB DAC + Headphone Amp [update]

February 8, 2017February 3, 2017 fustiniAudio, DAC, Headphones, music, usb2 Comments

It’s been a while since I last wrote *ahem* lies *cough* on this project. I am currently a little bit torn whether I should keep writing it here or start posting to my new hackaday.io presence… Anyway here is a brief update: TL;DR I now have a working standalone unit — USB in, headphone out […]

via Making Myself a USB DAC + Headphone Amp — Interim Update — Frog in the Well

Making a USB DAC and Headphone Amp

January 30, 2017January 27, 2017 fustiniAudio, DAC, usbLeave a comment

Yin Zhong designed this solution to use high-end studio headphones with his computer:

Making Myself a USB DAC + Headphone Amp

I need a DAC for my AKG K702. However, the more I looked at commercially available a.k.a. “audiophile” products, the more snake oil I smell. So even before I ordered my CEntrance DACPort Slim, I was already looking into how I can reinventing the wheel

I use OSHPark for prototyping PCBs. I decided to use their 4-layer FR-408 stackup simply for an un-broken ground layer. Turns out that the analog signals can easily fit on the top layer, so I allocated the power layer to the negative rail, and the bottom layer to positive rails.

The DAC + Filter module works! It produces reasonably clean line-level audio signal as expected.