DIY Hideout: How to make a Music Reactive or Dancing LED strip lights using LM324

In this post, I will show you how to make music reactive or dancing LED strip lights using LM324

If you prefer video mode or want to see the circuit working please click here to watch it on YouTube

Parts Required

1 * LM324
1 * BD139 NPN Transistor
2 * 1N4007
2 * 5.7k Ohm
2 * 10k Ohm
2 * 90k Ohm
1 * 5k Pot
1* 120 Ohm
1 * 2-way switch
1 * LED Strip light
1 * 12v LED Driver adapter or 12V power Supply
2 * 3.5mm Female Audio Jack

Theory

This project is based on the IC LM324 which is a Low Power Quad Op-Amp IC. LM324 consists of four independent high-gain, internally compensated operational amplifier designed to operate using a single power supply. LM324 generally operates between 3 to 30 Vdc.

In this project, we will be only using two op-amps out of the four.

The function of the BD139 NPN Transistor is to drive the LED strip. I recommend adding a heat sink to BD139 to protect it from overheating.

While choosing the driving transistor, make sure that your current requirement is met. In case your requirement is above 1.5A then I don't recommend using BD139. If your requirement is above 1.5A I recommend using MOSFET with a higher current rating.

The two-way switch is used to control the LED Strip Modes. 1. Light Mode: This is a normal mode that is directly connected to the GND and 2. Audio Mode: In this mode, the LED Strip light reacts according to the music.

Circuit Diagram

With Brightness Control - To control the brightness you can use the potentiometer