Sound/Audio Level Indicator

by calettso in Circuits > Audio

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Sound/Audio Level Indicator

Sound-level Indicator (Schematics available - FREE)

In this project, I will show you how to build a simple sound-level indicator using operational amplifiers.

Note: To ask questions, please visit my site at Ask the Expert.

Helpful Supplemental Videos:

Equipment:

  • Dual Power supply or two power supply sources.
  • Proto-typing board
  • Connection wires

Supplies

  • (11) - 741 Op-amps
  • (10) – 330Ω Resistors or (1) 4116R-1-331 and (2) 330Ω Resistors
  • (1) – 1KΩ Resistor
  • (1) – 1MΩ Resistor
  • (1) – DC-10-IDA (10-bar LEDs)
  • (1) – replacement headphone plug
  • (1) – replacement headphone jack

Connect the Amplifier Circuit From the Schematic Below One Part of the Proto-typing Board.

sound level - amp.png
amp-image.png

Connect the 10-bar LED Display Driver Circuit As Shown Below on a Different Portion of the Board.

sound level2 - amp.png
top-two-level-indicator.png

Note 1: Area in the yellow box in the schematic represents the area connected in the photo. You will need to connect the remaining 8 using the same or similar connection pattern.

Note 2: The images shows the 4116R-1-331 with the two 330Ω resistors in the lower left area of the image.

Helpful How to Videos:

Connect the Output of the Amplifier Circuit to the Input of the 10-bar LED Display Driver Circuit.

amp-out-soundlevel-in.png

Solder Wires to the Pins on the Replacement Headphone Plug and Jack.

plug.png
jack.png

Note: The plug shown is a mono plug and the jack is configured for a mono input. You may choose to configure your set up for stereo.

Helpful How to Videos:

At the Input of the Amplifier Circuit, Connect the Wires From the Replacement Headphone Plug and Jack.Note: Grounds(black Wires From the Plug and Jack and Ground From the Amplifier and Driver Circuits) All Connected Together.

jack-plug-added.png

Connect the Replacement Headphone Plug to the Music or Sound Source (example: Mp3 Player, Cell Phone, Stereo, Etc.).

source.png

Connect Speakers or Headphones to the Replacement Headphone Jack.

player-headphone.png

Turn on the Power Supply (or Power Supplies) to Power the Circuit.

power-supply-1-on.png
power-supply-2-on.png

Your power supply should be able to produce positive voltages (5V and variable voltage up to at least 10V) and negative voltage (variable to at least -10V).

Turn on the Music or Sound Source and Adjust the Volume Until at Minimum One Led Is on When No Sound Is Generated by the Music Source.

source-on.png
volume-adjust.png

Note: See video on how to make the adjustment to ensure one LED is on.

Play Sound or Music. Make Additional Adjustments to the Sound Level If Necessary.

volume-adjust.png

Note: Make additional adjustments on the music source.