Coin Toss App- Probability Grade 4 Math SOL 4.19

The Coin Toss App was a wonderfully different way to do an old and often used activity to teach probability- that of tossing a coin to gather data on the 50/ 50 chance of tossing heads or tails. One advantage of using this app rather than a "real" coin was the fact that the coin did not "fly" all over the room. One disadvantage to using this app is that after a few minutes of use, the app will not work any more.  It seems to have a time limit on its use.  I am still exploring the reason for this "glitch" in the app.  Any ideas from my followers would be appreciated!