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Picture of Volume Units Meter
INTRODUCTION AND DEFINITION
                         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
ABOUT THE IC
                           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.
                      
 
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Step 1: Things required (temporary)

Picture of Things required (temporary)
lm3916.jpg
connecting wires.jpg
Leds.jpg
potentiometer.jpg
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
http://www.instructables.com/id/Power-supply-5vconst-0-12v-variable/

Step 2: Things required (permanent)

Picture of Things required (permanent)
lm3916.jpg
Leds.jpg
potentiometer.jpg
soldering paste.jpg
soldering wire.jpg
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)

Picture of helping files(sechmatics/datasheet/layout)
vu meter schematics.png
vu meter layout.png
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

Picture of 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



 

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

Thank you.

usbg3rd (author)  mardikusumo1 year ago

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 :)

earbud-stereo-jack-plug-wiring.jpg
jcalangi1 year ago
Can you use microphone for this project and how? Pls reply..
usbg3rd (author)  jcalangi1 year ago

Yes u can attach a microphone with the vu-meter. see this link Step:5

http://www.instructables.com/id/10W-RMS-Audio-ampl...

just connect the two wires with the input terminal in the picture
Rate and like :)

mehrin111 year ago

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 :)

usbg3rd (author)  mehrin111 year ago

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.

deeppu2 years ago
can i use 6v adapter?
it is very nice ..
where you live?
can we friend
my fb IS DAZZLER KUMAR
usbg3rd (author)  deeppu2 years ago
yes u can use 5V adapter as it is mentioned in the data sheet
i live in Pakistan (rawalpindi).
and sure.