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Digital Volume Control

posted Jan 9, 2012, 3:02 AM by Andrew Jessop   [ updated Jan 22, 2012, 5:17 PM ]

Documenting my work on a digital volume control.

Background:

I was fascinated with audio and speakers at an early age; even before my father purchased my first 1W Amp kit from Dick Smith Electronics at age 11.  I enjoyed the concept of being able to share my enjoyment of music from my walkman with my friends at school.  Ever since I built that first kit I have been on an electronic journey for knowledge and satisfaction of my original goal - to share my enjoyment of music with others in the best way possible.

This specific project started in around grade 11 after I was introduced to Atmel AVR Microcontrollers.  It has taken a good many years to acquire all the knowledge required to piece this project together.  It has been the cornerstone of my extra-curricular engineering learning and provided me with motivation, purpose and enjoyment since I started.

It has taken on many incarnations over the years, however I will be only describing the present (and ongoing) version here.

Features:

* 4 RCA audio input w/ CD4066 digital controlled input switching
* LM1972 Digitally controlled analogue volume chip
* Network accessible via HTTP and a REST architecture using either ENC28J60 or RTL8019AS + NXP LCP2148 ARM
* TSOP4838 [pdf] IR Remote Sensor
* Rotary Encoders for volume and source selection

Software:

* lwIP or uIP embedded TCP/IP stack

Hardware:

Prototype

LPC2148 Dev Board - purchased from eBay
ENC28J60 Dev Board - purchased from eBay
 
CD4066 Analogue Demultiplexer Prototype
 
Custom LM1972 Board  


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