Auto Phone Speaker uses the proximity sensor and detects how you're holding your phone to automatically switch between audio output modes. Hold your phone at your ear and your phone will turn on the earpiece (and turn off the speakerphone). Remove the phone from your ear and it will automatically switch on the speakerphone (and turn off the earpiece). Extremely useful if a sudden hands-free situation arises (such as driving in a car) or you just want to include people around you into your phone conversation.
Auto Phone Speaker also features a microphone mute mode. Your phone will automatically mute the microphone when you move it away from your ear. It'll un-mute your microphone when you place the phone at your ear again. Improves privacy during phone calls and saves you from having to manually cover the phone when you don't want your caller to hear something.
Also includes an On-Off toggle button so you can disable Auto Phone Speaker when you don't need it.
You do not need to keep the app running in your multitasking tray for it to work. It will automatically run in the background as soon as you receive/place a phone call. Also, the app won't drain your battery because it only activates when a phone call is in progress.