Mobile cameraphones are really handy to have, but extra functions like zoom and focus are typically lacking. Engineer Bhautik Joshi decided to attach an SLR lens to his smartphone, and the results are actually pretty slick.
Joshi used an iPhone for his DIY project, but the idea should work just about any smartphone that has a built-in camera. He calls it the Phone-O-Scope, a smartly cobbled together out of things you may already have laying around the house (assuming you also have an SLR lens from a full-size camera).
Using little more than a cardboard tube, some sticky putty, duct tape (of course!), and a couple of PVC pipe couplers, Joshi made his Phone-O-Scope for a mere 10 bucks. Check out his blog post for step-by-step instructions on how he did it. (Be sure to scroll down to the results at the end of the post.)
Joshi calls the result of his project "pretty cheesy". We call it pretty cool.