We see a lot of LED matrix projects. They’re fun, and you can learn a lot of basic lessons during the build. But this one is out of the ordinary. [Rtty21] built an oddly sized, and sound controlled matrix shield for his Arduino. That’s it right there, the shield is the large chunk of protoboard but you can just see the Arduino peeking up over the top of it.
Now we say oddly sized because a 9×9 matrix doesn’t make much sense with an 8-bit micro controller. There’s no schematic but in the clip after the break he mentions that the columns and rows are driven by a decade counter and shift register and that’s what makes it possible to drive nine bits easily. Also of note on the board is that washer above and to the right of the matrix. It’s a touch-sensitive reset button. But the main control mechanism is a Clapper clone circuit. Just snap your fingers and it turns the project on or off. [Rtty21] based the design on this step-by-step sound input build.
http://www.youtube.com/watch?v=lb3sMFERdmk
Is that a piezobuzzer for the touch reset?
From the headline it made me think the thing made a loud snap when it started.
That’s be a neat feature for many things to scare the poo out of unsuspecting people, especially combined with a “magic smoke” device.
I wonder if it’s ‘almost’ 9×9.
Decade counter + 8 bit shift register gives you 80 outputs, one shy of 81 (9×9).
Dead pixel? What dead pixel?