U.S. voters bombarded with political advertisements can use a smartphone app to find out all about the groups behind them, its developers say. The Sunlight Foundation, a non-profit Washington, D.C., group working to increase transparency in government, has created the Ad Hawk app that uses a phone\'s microphone to listen to campaign ads and identify their source, NewScientist.com reported Tuesday. The app compares the audio portion of a radio or television political ad to a database maintained by the foundation, and can give the smartphone user information about which group sponsored the ad, where it\'s airing, and media reports about the sponsors. The technology is similar to that used to create digital \"fingerprints\" of popular songs for music-matching apps like Shazam or SoundHound. Ad Hawk follows the release of a similar app, called Super PAC app, which can reveal the funding sources of political campaigns. While Super PAC app is only available for Apple iOS, Ad Hawk is available for both iOS and Android.