Samsung Galaxy S4 supports a number of gestures that enable you to control the phone without even touching it. For instance, Air Gesture that lets you answers incoming calls without touching the phone. This hands-free feature is very useful in situations when you cannot touch your phone to receive a call, for example while driving. You can enable this feature to your non Galaxy S4 phones with an app called Air Call-Accept.
Air Call-Accept brings Samsung Galaxy S4’s Air Gesture like feature to other Android phones and lets you answer incoming calls without touching the phone. Just wave your hand over your phone to answer a call. As I told above, this feature has more practical uses while driving.
This application utilizes Proximity sensor of your device (most device has this sensor built-in) for this idea. The sensor detects your hand movement and triggers the answer button.
Usage of this app is simple. Just install and open it. Turn the service on and you’re ready to go! Answer your phone by waving over your phone (no need to touch the screen) or by putting it to your ear.
See below video to know it’s working while driving
Note: The free version of app supports only answer calls. The pro version offers other features such as reject calls, Speaker on when answer call and Send SMS when reject call.