Build an Arduino gadget that plays motion-activated sounds to scare off pests.
We are are going to build a cool Arduino device that plays sounds triggered by a motion detector. I'm sure you can think of many applications for this: visitor alerts, scaring cats off kitchen counters, sound an alert when you fall asleep in your chair and tip over, cubicle invasion alarm... I like it for protecting my garden from hungry pests. Out here in my little corner of the world we humans occupy 5 percent of the county. The fat deer, skunks, raccoons, and all the rest of the local animal kingdom that love my garden can jolly well dine elsewhere.