Jun 17, 2014

Back in Black - a DIY raspberry pi Boombox: Required Skills

For this project, you'll need a working knowledge of :
  • Adafruit's Neopixels
  • Rotary Encoders
  • Sure Electronics 0832 LED Matrix (or similar, such as the ones Adafruit sells); or the newer 3208 LED Matrix (differences explained below)
  • Sparkfun Spectrum Shield
Adafruit's UberGuide is an excellent tutorial on Neopixels. If you haven't worked with them before, this is required reading before you proceed. Neopixels have particular requirements - you can damage them by mishandling. Fair warning, read the tutorial.

Bob Rathbone has an excellent treatment on using rotary encoders with the raspberry pi. It can be downloaded from his site (PDF).

For the Sure Electronics 0832, I pieced together information from several sources. Although Sure still makes this LED Matrix, they have rev'ed the hardware. I'm including my findings here as legacy documentation.

The models are confusingly referred to sometimes as 0832, but also as 3208. The older 0832 model uses libraries for the HT1632 chipset; the newer 3208 uses the HT1632C chip set. As far as I can tell, the changeover to the new HT1632C occurred somewhere in the 2010-2011 time frame.  Per this blog based on the setup routine I used successfully,  I was using the 0832. My matrix was identified on the back as DE-DP10XV110. Newer models sport a DE-DP13111 / DE-DP13211 number on the back.  A good write-up on the Sure LED Matrix is available at makehackvoid. The color-to-model designation for the older 0832 seems to be:

  • DP104 = Red
  • DP105 = Green
  • DP106 = Yellow
(from milesburton.com)

I used the HT1632_LedMatrix library available here, simply because I had used it before and it worked with the 0832.Adafruit has a library for the current (as of June 2014) Sure 3208 model.

The Spectrum Shield is straightforward to use - one 3.5mm jack is audio input, the other audio output. Remember to order stackable female headers for using this with an Arduino, available on the same page as the Shield. The code for using the shield in this project is included on github.

John Boxall has written an exhaustive book, Arduino Workshop. He's also provided the book sections online. For the boombox project, I learned from John's work in Chapter 48, MSGEQ7 Spectrum Analyzer, using the Sparkfun Spectrum Shield. We'll be using that chapter later on in the build as a source for a test Arduino sketch.

Initial Setup, Next

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