Home-improvement projects are daunting enough without the worry of hidden wires and pipes. Walleye Technologies may have the solution: a handheld microwave camera that lets you see through walls. The device weighs less than 3 lb. (1.4 kg) and will cost less than $500 — it's smaller and cheaper than previous microwave imaging equipment — and it emits less radiation than a cell phone. It will be in hardware stores in 2010.