Tag Archives: audio

App note: The 2-Channel serial audio interface: A tutorial

via Dangerous Prototypes

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A pretty older application note about the serial audio interface by Cirrus Logic. Link here (PDF)

It may come as a surprise to those trying to make their initial investigation into audio systems design that there is a de-facto standard for transferring audio data within a system. Despite the differing naming conventions used within the industry, these apparently different interfaces are essentially identical. For the sake of simplicity, we will use the term Serial Audio Interface (SAI) in this discussion. The Serial Audio Interface is by far the most common mechanism used to transfer two channels of audio data between devices within a system; for instance, from the analogto-digital converter to the Digital Signal Processor (DSP) and then the digital-to-analog converter.

App note: The LM4935 headset and push-button detection guide

via Dangerous Prototypes

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Another headset plug-in detection from Texas Instruments. Link here (PDF)

The headset detect circuitry can differentiate between mono, stereo, mono with microphone, and stereo with microphone headsets. It can operate while the LM4935 is placed into low current standby mode, which promotes extended battery life. In standby mode, it consumes no extra current, if the headset has not been inserted into the headset jack.

App note: WM9712 Jack plug auto-detection, hookswitch detection and microphone headset detection

via Dangerous Prototypes

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App note on Cirrus Logic’s WM9712 jack plug auto-detection by monitoring the connected headphone resistance. Link here (PDF)

This application note describes two operations associated with using headset. The first is the facility to automatically switch between a mono ear speaker and stereo headphones for use in a Smartphone, PDA etc. The second operation is a method which can be used to detect if stereo headphones have been attached or if a mono headset with microphone has been attached.

flip-flop/BCF project

via Dangerous Prototypes

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Ray over at the diyAudio forum has been working on his flip-flop/BCF project:

I’ve just finished a project to roll up the developments into a more ‘finished’ build, feeding the balanced outputs from the flip-flop board into a Broskie BCF buffer stage. I’m using Nicks MJ Statistical Regulator for the B+ and one of Andrew’s indirect filament supplies

Project info at diyAudio forum.

NS1 Nanosynth the hackable analog synthesizer is back!

via Arduino Blog

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We’ve been playing with NS1 Nanosynth in the last few weeks, when it first appeared under our radars on the Christmas’ Gift Guides (while going sold out in few days, after Synthopia blessed it with this interesting review).  It’s a hackable and customizable analog synthesizer coupled with an Arduino Micro platform.

Personally, it was one of my first steps into modular synthesizers. Nice sounds, easy approach. Peter Kirn is perfectly picturing this amazing compromise here!

Synths: they’re fun to tweak and play. Modulars: they’re fun to patch. Arduinos: they’re fun to hack. Small things: they’re fun to carry around.

But how to track patches? How to share sounds with friends? I was playing mainly with my son, and managed to print out a paper sketch depicting all the different pinout of the synth. I wasn’t satisfied with that, I needed more!

I started writing Sound Machines, about new patches, more sounds. It turned out I made a Fritzing part out of the Nanonsynth, and we started sharing each other patches. This repository holds them, and this is a short review of the best. Enjoy!

 

Here you can listen to the envelope Generator (ADSR) in action:

 

Want to add your very own sounds? You can either add it to their repository or comment here!

Replacement LED driver for AN6877

via Dangerous Prototypes

aflevelmeter

Dilshan Jayakody writes:

AN6877 is linear AF level meter IC produced by Panasonic and it is commonly found on many audio equipment. This chip is no longer manufactured by Panasonic and finding replacement chip for AN6877 is also quiet difficult.
The circuit described in this article is design to replace AN6877 base LED drivers and it is based on commonly available components. This replacement LED driver is design using 10, MMBT3904/2N3904 transistors and it can easily modify to get necessary number of outputs.

Project info at Jayakody’s blog and elect.wikispaces.com.