We've seen small smartphone microscopes before, but they're either a bit shitty or a bit pricey -- problems neatly solved in this edition of Stuff You Didn't Realise You Could £-D Print.
It would appear that there's some kind of very specific version of Moore's Law that applies only to smartphone microscopes: a couple years ago, there was a version that cost $US30 and magnified up to x350; then there was a hacked-together $US10 one that used a laser pointer. Now, university researchers have managed to use a widely-available $US1 ball lens and a 3-D printed enclosure to achieve magnifications of up to x1000.
As always, once the researchers have managed to pull this feat off, they're then left to try and work out who could possibly need this. In this case, they have decided that the (no doubt very broad) target market is first responders dealing with potentially hazardous materials: they can just whip out their iPhones and scan the offending matter with their microscopes. Now, if only there was an app for that... [Gizmag]