This is an audio spectrum VU meter using the LoL Shield for Arduino .
The LoL Shield is a 14 x 9 LED matrix which fits onto the Arduino as a shield and is controlled through an efficient method known as Charlieplexing . It was designed by Jimmie P. Rodgers .
This project uses a Fast Fourier Transform library for Arduino to analyze an audio signal, break it up into frequency bands, and display that information on the LoL Shield.
The Arduino microcontroller is fast enough to calculate a fast Fourier transformation. It lives up to its name and is surprisingly fast and accurate.
Since all the work is done by the microcontroller, this project is completely portable if you use batteries.
Parts required:
- LoL Shield
- Arduino (Diavolino recommended)
- audio jack (I used a male mono 1/8″ phone plug)
- Arduino code
- power supply (DC power supply, USB cable, 9V battery, etc.)
Step 1: Assemble LoL Shield
Follow the instructions to assemble the LoL Shield here .
See, that didn’t take long at all!
Step 2: Solder wires to the audio jack
I am using a male mono 1/8″ phone plug, as it’s called at Radioshack, but you can use whatever audio cable is appropriate for your audio system setup. You could use a microphone if you wanted to.
For this type of plug, I soldered two wires. I used red and black.
The LoL Shield leaves analog pins 4 and 5 free for inputs. My code uses pin 5.
You can attach the red wire to analog pin 5 of the LoL Shield and the black wire to GND. You don’t need to solder it in, I just put the wire through and bent it.
