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DIY Microprocessor Sound Level Meter Demoed At MIT
An anonymous reader writes "A Piezoelectric Sound Level Meter was demoed at MIT's Battle of the Bands last month, borrowing its display from the do-it-yourself USB LED marquee that was the subject of a previous Slashdot story. This video tutorial describes in detail both the analog electronics plus the C code that runs the system. If this is your first experience at the intersection of digital and analog systems, don't be scared!"
LM3914 can handle 10 LED's per chip and can be cascaded for more. Add an amp for signal conditioning on the front end, and then hookup lots of LED's per line if you use a transistor to drive a bank of LED's.
They need a micro because their display is too complex for the job. But, make the display simple and you can make the whole design simple. Yet, since this is MIT's it has to be complex for some reason.
you may not find the lower level components interesting, but some people do. being interested in vintage amplifiers means that i am somewhat interested in what makes various older components sound the way they do. this led me to learn about the different characteristics of varying types of capacitors, which led me to trying to make my own capacitor out of foil and cling wrap. it certainly wasn't anywhere near the quality of a commercial capacitor, and even fell apart after being moved around too much, but it worked and i really enjoyed it and learnt from it. that doesn't mean i would want to try to rebuild a computer mainboard with diy capacitors (although i would certainly tip my hat to someone who pulls that off) but i don't see it as a waste of time in the slightest.
to each their own i guess.