This app will only work if your device supports ANT+. Some devices support ANT+ out of the box. For a list of them visit: http://www.thisisant.com/directory/filter/~/60/~/
Another way to use ANT+ is via an USB dongle.
If you have an ANT+ compatible device you can use this app to find CHIRP geocaches. Just start the app, turn Chirp search on and find a Chirp. Your device will warn you as soon as a Chirp is found. It will of course download the data from the Chirp so you can go and log that Geocache!