Graphic Equalizer Wall Art

May, 2013

I’m quite fond of interactive wall art.  When I came across the Freetronics Dot Matrix Display (DMD), I knew I had to make an interactive graphic equalizer to hang on my office wall.  Freetronics has a great blog that included sample Arduino code to get started.  I bought the necessary parts including an Arduino Uno and a Sparkfun Spectrum Shield and got it up and running quickly.

I found the provided 16-pin ribbon cable was not long enough for my needs, so I found a longer one on Amazon.  This gave me the length I needed to hang the LED display on the wall without also having to mount the Arduino.  I discovered that the Arduino-supplied power was sufficient for my needs, so did not run additional power to the DMD.  Extra power made the display almost blinding!

Next, I found the Velleman MK136 Super Stereo Ear kit.  It is an introductory soldering kit with 2 microphones, an IC amp, and a nice pot volume knob.  I removed the provided battery pack and extended wires down to the Arduino to get power.  Next, I mounted the Velleman board onto the Arduino case using 1/4″ standoffs.  I used a short stereo cable to connect the Velleman kit to the Spectrum Shield and tucked the excess wire into the case.  I further modified the Arduino case by cutting out a portion of the lid to provide room to connect the DMD connector using my Dremel Stylus (love this tool).

All was working well, but I didn’t like the fact that I kept forgetting to turn it off when I left the office.  So, I added a simple photo-resistor and attached it to an analog pin on the Arduino.  A simple modification to the code has it automatically turn off the display when the lights go off in my office.  I mounted the photo-resistor on the outside of the case and it works great.  Now I’m can enjoy it whenever I’m in the office and save energy when I’m not there.

It’s fun to have the kids come into my office and make weird noises just to watch the graphic equalizer.







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