Reading speaker voltages

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so i'm trying program addressable led strip react music i'm clueless how read-in speaker voltages. thinking of connecting 2 leads speaker (the input coming computer) , connecting arduino read voltages. ideas?

thanks in advance!

you can damage arduino if input negative voltage, , audio ac.  so @ minimum, need prevent negative voltage of the  audio getting arduino.

there few different solutions - simplest solution diode wired across arduino's input "short" negative voltages ground.*   then, need resistor before diode (1k - 10k) limit current don't damage audio circuit when diode "'turns on"'.  while you're @ it, diode wired other way arduino's 5v supply "short-out" current if signal ever goes on +5v, can damage arduino.

i use peak detector circuit (op-amp, diode, capacitor) change audio signal varying dc voltage.   i add resistor across capacitor (which not shown in peak detector schematics) peak voltage discharges in fraction of second, rahter holding "forever".    following peak dector buffer amplifier (an op-amp) peak-detector's capacitor sees high-impedance load (only it's resistor).    following resistor & diode "protection" circuit described above.   (the peak detector should never go negative, need protect posiotive over-voltage, , negative protection 1 more diode.)

quote
i thinking of connecting 2 leads speaker (the input coming computer)
ther 3 wires in connector/cable coming computer's audio jack.    left signal, right signal, , ground.   you need connect ground arduino's ground , 1 (or both) signal wires 1 of arduino's inputs.

fyi - signal coming out of computer called output.  @ other end of wire same signal goes into speaker, or into arduino, call input.  soundcards input getting sound computer. ;)

and, audio output soundcard not "speaker" output, , cannot directly connect 4-ohm or 8-ohm speaker. it's line-level, or headphone level signal.  puts-out 1v @ full volume.   computer speakers have amplifier built-in, , why need power supply.   it's signal arduino's analog inputs.

if connect speaker-outputs power amplifier, may high of signal, might need voltage divider (2 resistors) knock-down signal before connecting arduino.



* diode wired other way "block" negative current, doesnt work wekk, because diode doesn't turn-on 'till gets 1/2 volt across it, , block low-level signals.   the diode voltage-drop means you'll 1/2v negative if way suggested.   but, very-small negative voltage won't hurt arduino.


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