This project by Collin Cunningham will cover a number of concepts fundamental to analog electronics - frequency, filters, signal & ground relationship, etc. - as well as incorporating build techniques from past installments of the series.
Long before the dawn of digital music, folks employed the power of the electric color organ (aka “light organ”) to add some synced visuals to their hi-fi experience. Schematics for building such a beast based on AC power and incandescent bulbs can be be found fairly easily on the web, but plans for comparable LED-based designs seem a bit harder to come by.
Adapted from Aaron Cake’s 3 Channel Spectrum Analyzer, Collin built his own analog LED Color Organ to enhance the aural experience. The circuit uses 4 operational amplifiers plus ultra-bright 5mm LEDs to respond visually for bass, mid, and treble frequencies.