2007-03-24 23:28:03 · 2 answers · asked by dhennie 1 in Home & Garden ➔ Do It Yourself (DIY)
A microphone (or a speaker acting as one) provides a low voltage signal which is amplified. A circuit "listens" by accumulating the voltage and current so that an increased level has to be maintained for at least a minimum time before the higher level turns the remaining circuit circuit on. Normally the same accumlator circuit keeps the circuit from turning off instantly when sound ceases as when a speaker pauses to breathe. In its simplist form, a diode rectifies the AC sound signal to DC which is accumulated in a capacitor which is drained by a fairly high resistance, providing the delay. In fancier forms, a microprocessor might analyze the sounds for specific features that signify speech or breaking glass.
2007-03-25 02:36:59 · answer #1 · answered by Mike1942f 7 · 0⤊ 0⤋
yeah what he said!
2007-03-26 00:01:30 · answer #2 · answered by Anonymous · 0⤊ 0⤋