A few years ago a friend asked me to check the price of buzzer systems for a trivia game he wanted to present at a convention. To my horror and disbelief, the cheapest system which met his desires was going to cost several hundred dollars. I though to myself, I could do that, and the Triviomatic was born. Created entirely from things lying around my workshop, even I’m not entirely sure how it works. It has something to do with those silicon controlled rectifiers running across the top and a zener diode, though the original logic now escapes me. When operating on 12VDC, a small incandescent light will switch on indicating the first contestant to press their switch. A small bell also is triggered at that time. The master controller resets the system to ready status.
Update: When this was originally posted, it was several years after my construction of the device. Many people have asked for details on its operation, so I looked up more of the original information. I found the original website I based the circuitry on. The last circuit labeled “Game Show Timer” is the one I modified to fit the parts I had on hand. For the original schematic and information, please feel free to visit: www.techlib.com/electronics/games.html.