Time for a few upgrades. Since I can’t add anymore brain cells… I’ll settle for aids.
I tried the iPad with the fire timer. That was a fire fail because you have to deal with keeping it charged all day. Plus, it encourages students to play with their electronics.
And, what about breaks and time boxes? Yelling isn’t very kind and your voice will need all the reserved cycles it can get. Chimes are awesome and you can use them as a reward for games by letting the winner play the song.