A tennis ball that when activated will sound an alarm. A simple magnet and the remote is used to arm and disarm the device. Once armed only time and the remote can disarm the device. Its great as a way to break the silence. Use it around others to be even more exciting.
Step 1: Materials
1 - Doberman Security Toolbox Alarm ($15 Home Depot)
1 - Tennis Ball
--- I found a cheap window alarm for $1 at the dollar store, simply removed the batteries and housing from the casing.----
3 - LR44 Button cell batteries
1 - Casing for 3 LR44 batteries
-- Stand --
2 - Plastic or paper cups
Solder - for electronics
Exacto knife or razor knife
general purpose super glue (Picked up at dollar store for $1)
Clamps or device to hold in place while using the saw
saw, preferably one for cutting plastic.