A couple of months ago I acquired a Roborovski hamster. I caved in, despite swearing that I will never keep rodents again. Those little dark, moist eyes, like jet beads, are the thing that makes rodents so hard to resist for me, add in the comical little noses in constant motion, tiny, human-like hands, and soft, delicate, semitransparent ears covered with velvety fuzz, like flower petals, and you've got a powerful combination indeed. The cuteness level is on par with kittens here! This time what really reeled me in was the Roborovski's incredibly small stature. At the adult size of about 3" they are the world's smallest hamster. And voila, I brought the little fuzzy home.
Over the time that followed, I've learned two things. One: my little Hamham REALLY likes her wheel! And two: humans (i.e. myself), are infinitely more trainable than hamsters. All my attempts to hand-tame the new critter seemed to amount to was holding a desperately squirming little fuzzball as she first attempted to wriggle free, then emptied her cheek pouches of all the seeds she'd been hoarding there, in an attempt to become slimmer, and therefore more effective at wriggling free, then finally starting to chirp in terror and desperation, while peeing and pooping herself the whole time. Had I been a child, I would probably have happily ignored every sign of her distress, and, at some point, finally persuaded her that I wasn't trying to have her for lunch. However, having developed a bleeding heart as an adult, I couldn't stand torturing the poor thing for long. Result: one tamed human has restricted hamster-handling to a minimum necessary to maintain a clean cage. The Hamham had her revenge, too, running in her wheel so much every night, that it was sliding all around the cage and banging on the sides (and conveniently keeping me awake) until I finally figured out how to mount it on the wall of the plexiglass cage (at least that stopped the banging, though she still runs in it all night every night, and I can still hear it). Nowadays, before turning in, I look in on her, watch her bounce in her beloved wheel, and tell her: "That's right, run-a-way-way little Hamham! Quick! Run back home to Mongolia!"
That got me wondering: Roborovski hamsters hail from the Goby Desert and the surrounding areas. If her little wheel wasn't securely fastened to the side of her cage, could she run all the way to her native Mongolia? There are, of course, a few oceans in the way, probably a couple of mountain ranges, but what the hell, even "as the crow flies" (or hamster runs, as it may be), could she make it to Mongolia if there was a straight line path to follow, minus the obstacles?
Nothing to do for it, but figure it out.
Step 1: Dollar Store Find
While browsing through the Dollar Tree, looking for things to take apart for another project, I stumbled on this cute little gadget: a pedometer! Of course, this is not the deluxe model that calculates how far you walked and how many calories you burned, this one just counts the steps. This one just has a reset button, to flip the counter back to zero. I wonder if I could get it to count wheel revolutions instead? Turns out, I can!
I took off the back cover and had a look at the mechanism. Ah-hah, that's how it works! Basically, there's this little rotator arm held suspended above a contact lead by a spring. When the gadget is motionless, the arm is in equilibrium, and the circuit is open. If you jerk it a little (as would happen when you took a step), the arm swings down briefly and touches the lead, thereby closing the circuit. It then swings back up again, and after oscillating slightly, is once again held poised above the contact by its spring. Ridiculously simple, really.
All I'd have to do is have the wheel move the arm on each revolution, and I can count how many times it spins!
Please forgive the blurry pics here -- the pedometer is quite small, and this is the best macro photography my camera can muster. I tried to outline the important parts...