Volume Units Meter




                         This project is about how display an audio signal from a computer/mp3 (or any other media player device's) audio jack by glowing the LED's. Normally voltage is measured and displayed on an LCD or a seven segment display but displaying a voltage in this form is very simple and attractive
                        A Volume Unit (VU) meter or Standard Volume Indicator (SVI) is a device displaying a representation of the signal level in audio equipment.

                        Now the aim was to make a vu meter that senses the volume and accordingly glow led's ... the more the amplitude the more number of led's glow. the IC i have picked for this purpose is lm3916 Dot/Bar Display Driver
                           General Description
The LM3916 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs, LCDs or vacuum fluorescent displays, providing an electronic version of the popular VU meter. One pin changes the display from a bar graph to a moving dot display. LED current drive is regulated and programmable, eliminating the need for current limiting resistors. The whole display system can operate from a single supply as low as 3V or as high as 25V.
                            The IC contains an adjustable voltage reference and an accurate ten-step voltage divider. The high-impedance input buffer accepts signals down to ground and up to within 1.5V of the positive supply. Further, it needs no protection against
inputs of ±35V. The input buffer drives 10 individual comparators referenced to the precision divider. Accuracy is
typically better than 0.2 dB.
                             Audio applications include average or peak level indicators, and power meters. Replacing conventional meters with an LED bar graph results in a faster responding, more rugged display with high visibility that retains the ease of interpretation of an analog display.
                              The LM3916 is extremely easy to apply. A 1.2V full-scale meter requires only one resistor in addition to the ten LEDs. One more resistor programs the full-scale anywhere from 1.2V to 12V independent of supply voltage. LED brightness is easily controlled with a single pot.

Step 1: Things Required (temporary)


                         in-case u want to make a temporary project  u will need
*bread board
*ten LED's different color (your choice )
*a potentiometer 5k or at least greater than 2k
*an ic lm3916 dot/bar display driver
*connecting wires
* and a power supply (i use 12v power supply) or a 12V DC adapter

schematics of how to make connections  are uploaded in 3rd step

in case someone wants to make his/her own power supply here is the link

Step 2: Things Required (permanent)


                         in-case u want to make a permanent project  u will need
*PCB of 10cm x 10 cm at least
*ten LED's different color (your choice )
*a potentiometer 5k or at least greater than 2k
*an ic lm3916 dot/bar display driver
*Etching equipment
*soldering equipment
*Mini drill for drilling the through holes
* and a power supply (i use 12v power supply) or a 12V DC adapter

PCB layout  is uploaded in 3rd step

i used HCl (Mutaric acid) and H2O2 as etchant its perfect

Step 3: Helping Files(sechmatics/datasheet/layout)

Here are some of the helping material u might need for the project

*datasheet for the ic (in .pdf format)
*schematics (opens with proteus software)
*PCB layout (opens with proteus software)

Step 4: Video

Check this video i made it  just as a demonstration

in case of any problems u can mail me at dinitrogenoxide@ymail.com
Enjoy and if u like this instructable rate it and like the video

Make It Real Challenge

Participated in the
Make It Real Challenge



    • Games Contest

      Games Contest
    • Stone Concrete and Cement Contest

      Stone Concrete and Cement Contest
    • DIY Summer Camp Contest

      DIY Summer Camp Contest

    12 Discussions


    1 year ago

    I need a circuit to measure volume on a speaker level output (could convert to line level) then provide output which varies resistance based on level. Trying to use speaker level out to set volume of a second amp which uses simple wired potentiometer to set volume output. Any suggestions?

    1 reply

    Reply 1 year ago

    This VU meter can be used to do this. however this is not continuous. you can not get a continuous range from this circuit. However if you decide to divide your total resistance into 10 levels(you can increase and decrease this according to your need) and then depending upon these outputs you can connect transistors to activate different values of resistance in your second Amplifier.
    Let me know If something is confusing.


    2 years ago

    I made one with lm3915 but that ic was shortcircuited i replaced it with shop to 3916 i will make this.

    1 reply

    5 years ago on Introduction

    What is the function of potentiometer? How to know the wire from 3.5mm audio jack is ground and other?

    Thank you.

    1 reply

    Reply 5 years ago on Introduction

    Hi mardikusmo, the function of potentiometer is to control the sensitivity of the Vu meter like for example if u are playing a song that is at a very low volume u can change the sensitivity so that it divides the voltage on all the LED's otherwise only 2-3 LE:D's might glow due to less voltage.
    Secondly the sound is an alternating voltage signal i.e. it changes polarity every instance so u don't need to take care of ground.
    and still if u need to find the common wire the one labeled orange in the pic is common the other two are for left and right indivisually :)
    like and fav :)


    5 years ago on Introduction

    hi..its a nice project..however could u give in details,about the input signal..pls list the required components and the procedure to take the input... well thanks in advance :)

    1 reply

    Reply 5 years ago on Introduction

    Thank u :)
    u can take input from any media player /Mp3/mp4/Cell Phone/Computer device. all u have to do is buy a 3.5mm Audio Jack and solder 2 wires one one the ground terminal and the other connecting the other 2 terminals. now plug it in the computer and the other side in ur circuit.
    Thanks again.


    6 years ago on Introduction

    can i use 6v adapter?
    it is very nice ..
    where you live?
    can we friend

    1 reply

    Reply 6 years ago on Introduction

    yes u can use 5V adapter as it is mentioned in the data sheet
    i live in Pakistan (rawalpindi).
    and sure.