P-Comp Lab: Servos & Speakers

Self Servo

Servos are small motors with a 180º angle of movement. They can be precisely controlled. Or so I’m told.

My servo circuit worked. Sort of. If I turned to control too fast or as it reached the end of its range of movement it started to wobble like a fat man on a kayak.

I’m not exactly sure why this happened. Although I can poisit the potentiometer was the culprit from the Serial communication  feedback I was getting. At the high end of the potentiometer’s range (which was mapped to the high end of the servo’s range of movement) the numbers were jumping back and forth in a seemingly random pattern.

I’ll need to try this same set up with a more robust potentiometer and see what happens.

 Bringing the Noise

My little baby Arduino starter kit didn’t come with a speaker. So I went to the venerable Junk Shelf to see what I could find. (Spoiler alert: I found treasure.)  Photo Sep 23, 2 40 29 PM

I can’t tell you exactly where on the Junk Shelf I found this windfall. That would break the promise I made to the wizard who showed me the way. I can tell you what I found: a wireless phone handset.

Photo Sep 23, 2 40 57 PM

And tucked in the murky plastic shallows just beneath the outer layer I discovered a small speaker with clearly marked Power and Ground wires. Joy of joys! So I ripped it out, leaving a plastic carcass behind for the hands of fate/other ITPers to decide it’s ultimate destiny.

Photo Sep 23, 2 41 18 PM

The lab itself was fairly straight forward. I hooked up a circuit and followed the instructions to write a program that told the speaker to emit a series of short tones.

Photo Sep 20, 11 52 35 PM Next I implemented two photodetectors as “controls.” After a little tweaking and much flailing I did find that using only one of the photodetectors gave a more consistent sound from the speaker.

Photo Sep 21, 12 01 21 AM
what a shitty picture

At that point I also realized it was past 12:30am and whatever was emanating from my apartment must have sounded like I was trying to make love to an am radio. So that’s where I ended this lab.