Sound Reactive LED and LED STRIP

Hi friends in this article you can learn about how to make a sound reactive LED or sound reactive LED strip. Here the LED turns ON and OFF with respect to the beats of the music.These lights glow according to the length and pitch  of music beats, basically these are designed to pick the high intensity sound like Bass sound. So here you can learn how to synchronize lights with music.

Components Required

• Condenser Mic

• 2- NPN Transistor BC547

• Resistors- 10k (2),  1M (1), 1K(if using LED)

• Ceramic Capacitor 100nF

• 1 LED or LED Strip

• 9v Battery

• Breadboard and connecting wires

Working of Circuit

For LED

In this Simple LED Music Light Circuit, condenser mic picks up the sound signals and converts them into voltage levels. These voltage signals are further fed into R-C filter or HIGH PASS filter , to eliminate the noise from the sound. Further a NPN transistor ( BC547) is used to amplify the signals, from the High Pass filter. Then finally these music signals are given to the transistor. Transistor in this works as amplifier, and glows the  LEDs according to the sound pattern. This generates a very interesting sequence of dancing LEDs which follows the beats as per their intensity or pitch. We can also add more LEDs with transistor to make it cooler.

We can adjust the sensitivity of MIC by changing the value of 100nf and 1M, by using the formula for R-C filter:

 F = 1/ (2πRC)

F is the cut off frequency, means filter only allow frequency above than F. It can be easily deduced that more the value of RC, less the cut off frequency and higher the sensitivity of MIC. And higher the sensitive of circuit means MIC can pick low volume sounds, hence LEDs can glow on low pitch music also. So by adjusting its sensitivity we can make it less sensitive to reacts only on high note beats or we can also make it more sensitive to react on every little beat in the music. Here we have set its sensitivity at moderate level.

Condenser Mic should be connected properly in the circuit, according to its polarity. To determine the polarity of MIC one should look at mic terminals, the terminal which have three soldering lines, is the negative terminal.

Transistor BC547 is a NPN transistor, which is used as a Amplifier here. NPN transistor acts as a open switch when there is no voltage applied on its Base (B) and it acts as closed switch when these is some voltage at its base. Generally 0.7 volt is enough to get it fully conducted. 

For LED strip

The circuit is as similar as used for LED but the difference is that the change of LED into LED strip and removing the resistor and providing enough supply needed for led strip .