How to Make Stereo VU Meter

What is a VU meter circuit?

A VU meter is also an audio Visualizer that has a group of LEDs as dot or Bar display. VU meters are basically used with the Amplifiers and audio systems to analyze and display the audio spectrum. The LED dot or bar display lights up LEDs-high to low showing the level of the pitch with matching the pattern of bass going high or low. Here in this article, I am going to discuss a VU meter Circuit using the LM3915 IC.

PCB:-

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PCB order steps on PCBWay:

• Visit the website: www.pcbway.com
• Click PCB Instant QuoteClick
• quick-order PCB Upload the gerber file by clicking "+Add Gerber File" and wait until the gerber file is finished
• uploading Set the PCB specifications as you wish, starting from the number of PCBs, the number of layers, thickness, color and others.
• After that, look at the left, it will display the estimated cost
• processing time and delivery service selected
• Click Save to cart

ASSEMBLING COMPONENTS ON PCB:-

Connect the components to the PCB

We are building a stereo VU meter here. So I am using 10 green led, 6 yellow led and 4 red led here. You can use any color led you like...

IC LM3915 is an 18pin monolithic Integrated Circuit that senses the analog signal voltage levels and accordingly drives 10 LEDs Bar or dot Matrix display. Being stereo we are using 2 IC here

The capacitor is used to get a good output

With this, our PCB work is completed...

It has 2 modes

• Bar Mode: To select the Bar mode you have to connect a jumper pin on PCB (connect the Pin 9 of LM3915 to the Vin)
• Dot Mode : To select the Dot mode leave the jumper pin on PCB (leave the Pin 9 of LM3915 open)

CONNECTION DIAGRAM:-

I am using 12v supply here.

Instead of lm3915 you can use 3514 and 3516

Difference of LM3914 & LM3915 & LM3916

• LM3914N will display an amplitude of a signal in Linear form.
• LM3915N will display the signal in Logarithm form.
• LM3916N: Update The outputs can drive, LCDs, vacuum fluorescents, and incandescent bulbs, as well as LEDs of any color

Normally if using the amplitude of the sound signal. We should use the LM3915N.

WORKING:-