Here is a tiny gadget that turns your iPhone into a bat detector. The Echo Meter Touch 2 lets you listen and record echolocation calls, which happen to be out of the range of human hearing. The sounds are visualized on your smartphone.
The app comes with algorithms to analyze the echolocation calls and identify bat species. You can click on each species to learn more about each bat. The app also captures the location of each recording.[where to get it]