That's not as easy as it sounds, or more correctly, while its easy to get an LED to flash to the music, its less easy for it to be useful and meaningful.
Understand the problems and you'll see why.
Music has lots of transient peaks. So you decide you want an LED to light at a given level. Thats a problem because the transient nature of the signal means the light from the LED is transient too. In other words dim brief flashes when the signal exceeds some value.
What is nedded is a circuit to rectify the signal (so that peaks above and below "zero" are registered and treated equally and a circuit to add a time constant so that the peaks are "held".
Now all that can be done with a couple of opamps for one LED.
What I recommend is you consider a circuit based on the LM3914 series of chips.
Here's a great on-line resource for data sheets for 99% of the devices you'll ever need,
Datasheet catalog for integrated circuits, diodes, triacs, and other semiconductors, view
Look up LM3914, LM3915, and LM3916
If you look down the data sheet you'll see how the circuit is comprised of a chain of opamps each with a different fixed reference voltage on one input and the variable audio on the other.
Each opamp configured like that forms a "Window comparator"
Understand the problems and you'll see why.
Music has lots of transient peaks. So you decide you want an LED to light at a given level. Thats a problem because the transient nature of the signal means the light from the LED is transient too. In other words dim brief flashes when the signal exceeds some value.
What is nedded is a circuit to rectify the signal (so that peaks above and below "zero" are registered and treated equally and a circuit to add a time constant so that the peaks are "held".
Now all that can be done with a couple of opamps for one LED.
What I recommend is you consider a circuit based on the LM3914 series of chips.
Here's a great on-line resource for data sheets for 99% of the devices you'll ever need,
Datasheet catalog for integrated circuits, diodes, triacs, and other semiconductors, view
Look up LM3914, LM3915, and LM3916
If you look down the data sheet you'll see how the circuit is comprised of a chain of opamps each with a different fixed reference voltage on one input and the variable audio on the other.
Each opamp configured like that forms a "Window comparator"
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