This is what led [Dirk] to create human-powered, battery-free laser guns with software to track and display hits. In the image above, red laser hits on the target are detected and displayed on the ...

There’s nothing quite like [Elliot]’s cherubic sense of wonder and maniacal laughter after he tests his fully automatic AA battery-launching air gun. That fires 600 rounds a minute.

But have you used Ryobi's battery-operated grease gun? Home Depot also features other selections of battery-operated grease guns, including the Milwaukee M18 18V cordless gun at $229. The battery ...