USB Interruptor

Teensy creator Paul Stoffregen designed this board to momentarily disconnect a USB device:

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USB Interruptor

This simple board plugs inline with a USB cable. It always passes the 5V power and normally passes the USB data signals. But when you press the button, the USB data signals are momentarily disconnected.
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For the last few months I’ve been developing a USB Host Library for powerful but complex EHCI USB port in Teensy 3.6 [..] Reaching over to physically unplug the USB cable gets old quickly! Really, really old, both hands off my keyboard… right when trying to focus [..]  I made this handy little board with a proper USB 2.0 high speed mux chip. The control signal is just 3.3V logic, so I might even wire it up to something to automate the process.
PaulStoffregen has shared the board on OSH Park:

USB Interruptor

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USB Interruptor

Prototype of USB DAC + Headphone Amp

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

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First Complete Prototype

In the interim update post I posted the plan for integration into 2 boards: A 2-layer power board, and a 4-layer main board. Actually I have had a good copy of the main board for quite a while: Story for the power board is not as good though. In the beginning I screwed up on […]

Prototype of USB DAC + Headphone Amp

XMOS-based USB to I2S bridge

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)

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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

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XMOS-based USB to I2S bridge

Making a USB DAC + Headphone Amp [update]

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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 + Headphone Amp [update]

Cypress FX2LP High-Speed USB Controller

Yin Zhong designed this dev board for Cypress FX2LP™ microcontroller:

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μ-68013: a High Speed USB2.0 MCU breakout

Cypress’s FX2LP (CY7C6801x) is one of the smallest footprint MCUs that offer a high-speed USB (480 Mbit/s) device peripheral with built-in PHY (many others lack the PHY!). It contains a 8051 core for bookkeeping and setting up data streams through its hardware multiplexed parallel FIFO interface to/from an external processor, be it MCU, DSP, or FPGA/CPLD.

This is a breadboard-friendly minimal system PCB for CY7C68013 in QFN56 package. It integrates 3.3 V power supply, core clock, reset circuit/button, and I2C EEPROM (the MCU does not have built-in flash). It breaks out all IO pins through 2 rows x 20 pins 0.1″ pitch headers with 0.7″ row spacing.

summivox has shared the board on OSH Park:

20170112-0057 CY7C68013-v1.0.zip

3ff564ec93a66d415384b740fe7db92f.png Order from OSH Park

Cypress FX2LP High-Speed USB Controller

Making a USB DAC and Headphone Amp

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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

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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.

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

 

Making a USB DAC and Headphone Amp

USB-to-1-wire Interface

Alan Mitchell designed this board to interface 1-wire sensors to a Raspberry Pi computer:

USB-to-1-wire Interface

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This board is part of Alan’s Raspberry Pi data collection system:

Mini-Monitor

The Mini-Monitor software is data acquisition software that runs on a Raspberry Pi computer. It is designed to post the collected data to the BMON web-based sensor reading database and analysis software, but the software can be modified to post to other Internet databases. The Mini-Monitor software has the ability to collect data from a number of different sources

USB-to-1-wire Interface