LED Brightness by volume

[AnonymousDetroit]

Hi, Anonymous here.

We're making a special mask for the detroit protest, and we need help.

What sort of things do I need to do, to make it so LED's will glow in relation to input volume. Like, we want to put two red LED's in the eye sockets of a gas mask and make them glow according to the internal volume of the mask, like when the wearer speaks.

 

[mister_rf]

Maybe You can use a simple transistor to do this...
Value for resistor R is related to the supply voltage and maximum LED current.

R=(Vcc-3V)/I led
I led=20-40mA

At 5V you need 47-100 ohms.

 

[kiprono]

Ensure part of the supply voltage to the LEDs is derived from the signal to the speaker.