Bob Knetzger

Bob Knetzger

Bob Knetzger ([email protected]) is an inventor/designer with 30 years of experience making fun stuff.

Latest from Bob Knetzger


Ordinary kaleidoscopes must be pointed toward a light source to work. This one has built-in illumination, so you can hold it right up against a printed page. Read more »


It’s a hard road, but hardly impossible. The following five experts have found success with their toy creations, and have supplied their tips and advice to help smooth a successful toy-making pathway for you. Read more »


Make this fun mini projector just in time for Halloween. It throws a shadow image of a black cat — which then disappears, leaving only his spooky grin! Read more »


Here’s a classic toy reimagined for you to make just in time for Halloween candy-giving and party fun. It’s the Mad Monster Candy Snatch game, which combines the nerve-wracking dexterity of the old classic Operation game (BZZZZZT!) with a fun monster head–shaped candy dispenser. Make those little goblins earn their... Read more »


Suppose you wanted to build electronic dice for a board game. Sure, you could use discrete components to build a clock circuit into a decade counter and BCD to 7-segment decoder, etc. Or you could write some random number generating code. That’s obvious and has been done before. But professional... Read more »


My son was frustrated that the original battery cover on his Lotus Elise sports car wouldn’t quite fit over his new, larger battery. It was the perfect opportunity to try out my new strip heater by making a new cover. Read more »


Reminisce about the melodic toys of yesteryear and learn how to make your own. Read more »