This project is simple to build and use yet accurate enough to provide a count down from any time interval anywhere from ninety-nine minutes down to one minute. The bright two digit display shows the current minutes left, and there is a piezo buzzer to indicate when the count reaches zero!Main Features– Countdown period 1 minute to 99 minutes– 2-digit 7-segment LED display– 3-button control– Low power consumption– 3-volts battery supply– AT90S1200 microcontroller chipTo use the timer is simplicity itself. First, select the time you require, by pressing the two appropriate push buttons. For example, press the unit button once for 1×1 minute, and the tens of unit button, say, three times for 3×10 minutes. There you are: a 31-minute countdown period. As you press the two switches, the number will show on the double- digit display. Both buttons will allow you to loop continuously from nought to nine, and back to nought .