DIY Kits AT89C2051 Electronic Clock Suite Electronic Parts and ComponentsDirections for use - Function keys: S1 - function selection button， S2 - function extension buttons， S3 - value add to 1 button. - Functions and operation instructions: when operating， for a short period of time (less than 1 second) press S1， can be in more than six function continuous loop. Midway if long press (more than 2 seconds) S1， immediately return to the clock function state. - clock function: after electrify display 10:10:00 namely - Adjust the function of time: Short press S1 at once， that is， the current time as the flashing status， press S2 is hours plus 1， press the S3 is minutes plus 1， second not adjustable - the alarm clock function: short press the second S1， display status for 22:10:00， colon for long light. Press S2 is hours plus 1， press the S3 is minutes plus 1， second is adjustable. It will display - : -- : -- when press more than 23 hours ，means shut the alarm clock function. As the buzzer alarm sirens for 3 seconds - the countdown function: short press S1 three times， display status is 0. Press S2 displayed a high， from low to press S3 is corresponding plus 1， when press S2 with 7 times in set time state， start the countdown， again press S2 will once again into the adjustment function， and stop the countdown - stopwatch function: short press S1 four times， display status is 00:00:00， colon for long light. Press S2 start stopwatch， again press S2 is stop timing， press S3 is a stopwatch reset when stop timing - counter function: five short press S1 and displays a status for 00:00:00， press S2 counter plus 1， press the S3 counter resetPackage Includes - 1x DIY Kits AT89C2051 Electronic Clock Suite Electronic Parts and Components