Project concept - large VU meter

I have an idea for a project. The electronics are pretty straight forward, the programming...not so much. Looking for help.

The idea.

I want to build a large VU meter (sound intensity meter). I want it to be 7-8 feet tall and have 10 intensity bars. As the sound get more intense (kids yelling) more bars are lit.

I have a SparkFun redboard (arduino copycat) with a sound detector card (microphone puts out: GATE, ENVELOPE and ANALOG).

The plan is to use 10 digital outputs from the Redboard. The outputs would fire to 5v relays. The relays would light up 10 leds in each intensity panel from a 5v/.5A "wall wart" power supply.

The sound detector has pins for a pot, adjustable resistance filter.

Now for the help.
I am a novice at programming.
I need the incoming analog signal to be processed to output different sound intensity levels.

Hope this has been written well enough to understand my need and descriptive enough that someone can conjure up the magical code to make my dream come true.

Thanks in advance.

Use mosfets rather than mechanical relays for faster response, less noise and longer life.

Hi Roy Hicken,

This sounds cool!

Start out by building a small scale model of the device so you can learn how to make the program without burning anything out. Use 10 regular LEDs that you can power directly from your 'redboard'. For the LEDs, you can use discrete LEDs, or get one of these packages with 10 bar shaped LEDs in an IC shaped component.

Hook it up to your 10 output pins. Hook the ANALOG pin of your sound detector to an input pin on the redboard. In your sketch, use a series of if statements (or a single switch statement) to turn on LEDs depending on the value returned by analogRead(soundPin).

Give it a try, and if it doesn't work for you come back here, with your code, a circuit diagram, and any other information that will make it easier to help. Once you get your scale model running like you want, go BIG.

Thanks guys.
@mikb55 I looked into the MOSFETs. Interesting. I'll have to figure out how they work (new to electronic but willing to learn)

@ChrisTenone That was my plan. Still kinda weak on the "series of IF" statements. Been decades since I did any kind of code writing. I dust off the cobwebs...

Thanks again for the input.

[u]if statements[/u]

Just start simple with one LED and expand from there.

I have a SparkFun redboard (arduino copycat) with a sound detector card (microphone puts out: GATE, ENVELOPE and ANALOG).

I don't have that board, but I believe the ENVELOPE output is the one to use.

Just FYI - There is an LM39185 VU Meter chip. You could probably use it with your microphone board... It would be cheaper than the Arduino, and no programming required!

I made an 8-foot VU meter "effect", but my computer crashed and I don't have the code (the code is specific to my hardware anyway). It's an effect, so it doesn't read in dB and it self-calibrates to the average loudness (which means it's not actually calibrated). Mine is Arduino based, and it can be reversed or inverted, switched between the dot & bar mode, and it does several other different flashing/sequencing effects. It's driven by a line-level audio signal (no microphone/acoustic input).

My meter is 24 regular "high brightness" LEDs per side, mounted in a black plastic pipe, and spaced about 3 inches apart. They are driven by serially-addressed LED drivers (so I only need 3 output pins to address all 48 LEDs.