This short collection of projects - some useful, some instructive, and some amusing - can be made for around 10 UK pounds (16 US dollars). The estimated cost does not include an enclosure (box). All of the projects are battery powered, so are safe to build.

Our first project in this series is a handy device for timing eggs, telephone calls, player’s moves in games like chess, and for how long you brush your teeth!

The popularity of a boiled egg as a breakfast dish has ensured that an egg timer is a useful yet simple project for a beginner to build. Almost everyone needs such a timer. However, it is generally cheaper to buy one than to make one, so why bother? Perhaps one of the main reasons is that the home-constructed device can be readily customized to your preferences, as can the circuit presented here.

Also, there is the novelty factor, of which this timer is a good instance. The author has been designing timers for almost as long as the advent of the 555 timer IC made this an easy thing to do. Each has had its own particular gimmick. Now we have the very latest word in timers – one that has no switches or buttons.

It is as simple to operate as the old-fashioned sandglass timer. Just turn it over and watch for all the sand to run through, only in this case watch for the LED to light. In addition, since this is the last word in timers (at least until the next one is hatched!), we call it the Ultimate Egg Timer.