"If you are happy and you know it CLAP your hand", LOL that is a really useful and fun app to have. To make the app really works, I guess your phone must be able to detect and distinguish the clapping sound. Since sounds are measured in decibles, I'm not really sure how loud you need to clap before it can detect and react to it. The only way to find out the answer is to install and test it using various types of phones. Good Hunt!