I first built a set of quiz buzzers a few years ago, but have recently significantly modified them, particularly for use as part of a messy games day for a Scout camp Gameshows. The system is built almost entirely from scrap or parts salvaged from old equipment.
The system consists of two contestant stations. These are physically based on some offcuts of 12mm ply, mounted to a base made from the sides of a cable drum and connected together using a pair of key-klamp bases and a length of scaffold bar. The top surface has a team identifier made from a length of square drainpipe and covered in sparkly holographic book covering sticky backed plastic. Two industrial indicator lamps are mounted to the tube to identify which team responded first. Behind this is mounted a surplus ‘big red knob’, an industrial palm switch. These two parts are cable together and a cable run back to a central compere control.
I looked at using a commercial kit for the central control, but ended up deciding that once I’d substituted a commercial circuit with external relays to drive more powerful lights and buzzers and ended up with a dual voltage unit, I would be better building a relay based logic system from scratch. Despite some searching in the web, I didn’t find suitable circuit so developed my own. Details are on the PDF drawing that can be downloaded from this site if you want to build your own.
The circuit can be built to operate on any voltage desired, dependent on the component choices. I chose 24V as I had suitable industrial lamps, sounder and DPCO relays and holders in stock. The central control was built into a surplus box wiring up each part directly which was effective, albeit a little untidy.
In use, the system worked very well. The only downside is that outside the sounder could have been louder, but that is easily solved.
The Button and Display