With a tiny-enough GPS sensor, it’s possible to track the location of anything from your lost keys to a runaway pet. That’s because the world’s smallest GPS receiver is now smaller than a penny and weighs only 0.3 grams. But that’s just the chip — what about all the electronics required to make it truly useful, like a system for remotely downloading the data it has logged? This GPS logger weighs 10 grams, most of which is battery. Custom-made by Telemetry Solutions of Concord, California, it’s small enough to attach to a fruit bat for research purposes. Data can be downloaded directly from the chip upon recapture, or it can be downloaded wirelessly from up to 500 meters away.