Making Furniture Interactive

September 11, 2007

big steamy pile of failure

Filed under: Exercise 2: Add a Switch,Jenn Gooch — jenngooch @ 6:47 pm

Um, yeah. So I wanted to add a simple “The Clapper” style switch to my lamp, which would turn on and off with a loud sound, like a clap. I was going to throw in a Piezo Film Vibra Tab, which I’d used before, and be done – or at least concentrate on fine-tuning other parts of the code/lamp.

Turns out I don’t have a Piezo Film Vibra Tab, though I did (someone “borrowed” it). A friend, Gregory Witt, suggested I make my own with a speaker (preferably a mic, but I only had speakers) and an op-amp as a comparator. I wasn’t able to drop the voltage down enough to compare what little voltage the speaker was kicking out upon clapping, so I then hooked it up through the amplifier side of the op amp and used the comparator on the amplified signal. At this point the schematic Greg developed for the op-amp looked like this:

op amp schematic

I was getting so much noise, but still not picking up a clap. Tried putting in a few capacitors. Still so noisy that it would have taken forever trying to find out where the noise was coming from, what kind of noise it was, and how to fix it.

op amp

In the end I ended up with countless hours, which I won’t call wasted, but they definitely were not productive in that I didn’t end up with a product other than frustration.

So I did what anyone would do in my situation – I gave up. I slapped a non-creative switch on it just to show I could. It already had a photoresistor. And it’s still sticky.


Thanks to Greg who always cringes when I come in his studio because it means I probably need to bum a resistor or ask him annoying questions in my attempt to bolster my astounding ineptitude with all this.


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