Audio Visualiser Part 1 : The Microphone Pre-amplifier

A project log for Arduino Radio

Let there be music ... everywhere.

Xtreme TechXtreme Tech 03/27/2023 at 06:040 Comments

The radio is almost done - but nothing is really complete without LEDs right ?

As someone who loves both music and LEDs, I'm always on the lookout for ways to combine the two and recently I came across the idea of an audio visualiser. I started out by purchasing a sound detection module which made use of the LM393 IC and an electret microphone. 

                                                                Sound detection module

However, after multiple tests, I realised that for some reason this module was not able to detect the noise levels in the environment. This left me with no choice but to search for alternatives. After extensive research I came across this circuit :

                          Source :

This is a microphone pre-amplifier circuit which makes use of the LM386 amplifier. Excited by the prospect of finally getting my LED visualiser up and running I procured the required parts I began building the circuit. However, due to unavailability of parts, I had to make some substitutions : 

1. instead of a 47nF capacitor I used two 100nF capacitors in series.

2. instead of a 10 ohm resistor I used two 22 ohm resistor in parallel. 

After about an hour of building, this is how my circuit turned out :

Anxious but at the same time hopeful I connected this circuit to the Arduino nano board and ran my test code. The analogue values ranging between 0 to 100 began to pop up on my screen but the biggest question was will it detect noise ?

Clap ! 749. That was the value which appeared on my serial monitor when I made a loud clap above my electret microphone. It was able to detect the change in sound levels. I tested the circuit with songs and once again it worked flawlessly. 

My next step would be to add a NeoPixel ring to this project and sync the music with the lights using the circuit I have constructed above. Until then, I hope you have a great day and keep an eye out for the next blog post which will be coming out soon !