2015.06.08

Yeahs! Pi!

I presented A Life Time of Yeahs! at Bay View Gallery Night but I didn’t really post much about how it was made, so I’ll do that now, as well as talk about the shortcomings. Above you can see the front and the back. The front piece is actually from an IKEA picture frame I found in the trash. It was a nice smooth MDF-like surface, so I figured it would take the vinyl and paint pretty well.

For the illustration of Mr. Rollins I did a few searches and didn’t find anything that was perfect, so I grabbed a few images as reference and traced/drew my own in Inkscape. I then created a stencil by cutting vinyl on the Silhouette Cameo (including the lettering) and stuck it all down to the IKEA board which I had already painted white.

With the vinyl in place I then painted it all flat black. I didn’t leave it all smooth as it sort of looked too polished, so I smeared some paint around with a brush and then with my fingers so it gave it some texture. I’m still not sure that was the right thing to do, but I did it, and there’s no going back.

Once I had the front piece done I found some scrap wood for the frame in my garage and cut it on the table saw. I made sure the wood was wide enough to fit the speakers into. It was, but as I’ll get to in a bit, wider would have been better…

Yeahs!

The back of the piece contains a Raspberry Pi, a set of speakers, and a Teensy 3.0 with a few buttons connected to it. It’s all powered by a power bank from Brown Dog Gadgets.)

The speakers are USB powered so they, along with the Raspberry Pi, connect to the power bank. Turning on the power bank boots up the Pi and starts a script called “rpisounds.pl” which is a Perl script that starts running and waits for keyboard input to do something. That “something” is playing an audio file if you press the red button on the front of the piece. There’s also a small button on the back of the piece that safely shuts down the Pi if you want to turn it all off.

Yeahs! Pi!

It’s been suggested that the Teensy in addition to the Raspberry Pi is overkill, and… it is! I originally had a separate project that used some of this code and hardware and ended up just grabbing what I had lying around because it was quick and easy. Sometimes it works out that way, and that’s fine…

I should have gone with the more powerful speakers I had, because as I learned last time, if you’re doing something with audio in a public space, make it much louder than you think it should be. I had a louder pair of speakers, but they would have required AC power, so I compromised. Oh well. (You can’t tell from the photo, but there are speaker hole drilled in the side of the frame.)

I’ll probably clean up the code and publish it eventually, but essentially it gets kicked off by /etc/rc.local and runs it a continual loop waiting for a key to be pressed. If you press “a” (the button on the front) it randomly selects a WAV file and plays it. If you press the button on the back the script sees a “r” and shuts down. Why an “r” instead of an “s”? I don’t know… There’s another button that was taped up that types a “q” for quit, which quits the script, and is handy for debugging or troubleshooting if you have a monitor and keyboard attached.

That’s the summary of my Raspberry Pi based interactive painting titled “A Life Time of Yeahs!”

I hope you enjoyed it… As always, let me know if you have any questions.

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