Arduino VU Meter




Introduction: Arduino VU Meter

I am an electrical engineer and an Arduino and electronics enthusiasts. I believe working with el...

Lets make a simple Arduino VU meter!!!

Step 1: Components

· LM386 operational amplifier

· Electret microphone condenser

· Arduino duemilanove

· 10k potentiometer

· Capacitors: 47 nF, 1uF, 10uF, 100uF, 100nF

· Resistors: 10Ω, 22k

· 6 LEDs

To distinguish between the electret positive and negative terminal, perform a continuity test. Measure the resistance between each pin/terminal and the outer casing of the electret. The resistance between the negative pin and the casing should be zero, since they are connected.

Also make sure you understand the LM386 pin configuration as shown in the diagram

Step 2: Electret Circuit

Connect the positive pin of the electret to a 22k resistor and then to the 5v of the arduino.

Connect a capacitor in parallel with the 22k resistor. The capacitor cathode should then connect to the amplifier circuit

Step 3: Amplifier Circuit

The connection is done as shown above. That is why it is important for you to learn the LM386 pin numbers that i showed you in a previous image.

Pin 1 and 8 are not connected to anything, since i will be using the default gain (20x)

Pin 2 and 4 are connected to ground

Pin 3 is is the input and is connected to the input (10k potentiometer slider)

Pin 5 is the output. Its connected to a 47nF capacitor (current bank) and a 10 ohm pulldown resistor. The output is tapped from the pin before the current bank connection.

Pin 6 is connected to 5v

Pin 7 is connected to a 1uF cap and then to ground

Step 4: Video

Step 5: Complete Setup

Here is the complete setup. Upload the code below and enjoy the show.

To learn more about the arduino VU meter and LM386+electret circuit, please visit the link below:



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    15 Discussions

    you have included 'Serial.begin(9600);'

    but what is being shown in the serial monitor??

    I just put extra 270ohm resistors for leds and did some delay in a code. To fade out more natural, more analog console way. Fun build! Thanks!

    2 replies

    add some capacitors instead of resistors to the leds in parralel

    can i conect the eletrect directly to the LM386 without the potentiometer ?

    will this work with an arduino leonardo?

    I will adapt your instructables on my Led Cube 8x8x8

    Thanks ;)

    Hi yhtomitsy. Thanks for the instructable. I have hooked up (what appears to be) your circuit on a breadboard, but i can't get it to work... Using the pot i can get the LED's to light up properly, but there is no sound sensitivity at all. Instead it somehow works like a proximity meter with the display going up, as i move my hand near the board. I have ensured that the electret is positioned right, of course.Do you have any idea, what i could have done wrong?

    1 reply

    I havent done it before, however, please check out this forum. I think it has exactly what you need

    Very nicely done! Can the electret mic be hooked up to the Arduino without a amplifier? Man I was just getting into the song when my internet failed :)

    2 replies

    Yes it can, however its sensitivity is decreased. Check out this link for the instructions on how to do it

    Thanks a lot for the timely reply! I'll have to do this soon. I'll post a pic when I'm done :D