4 Bits AT89C2051 based DIY Digital Electronic Clock

Function description:

• Normal working, hours/minutes display.
• The hours/minutes are adjustable and independent;
• The second time correction function.
• Running can fine-tune the clock speed, 0-9 file is adjustable, in 5 files by default.
• Two way alarm clock, and can set alarm switch independently.
• The hour prompt function, and can close the opening hour prompt functions.
• Equipped with battery interface, can run when power supply drop. Working with greater than 3V battery. Use two 5 batteries, three 5 batteries, or cell phone battery is ok.
• The countdown function, and can be implemented within 99 minutes of the countdown, alarm, the end of the countdown.
• Stopwatch function, can realize stopwatch function, can suspend a stopwatch, reset a stopwatch.
• Can realize counter function, can record keystrokes. It can also record the external pulse number.

Description:

• Voltage: DC 3.7V-5.5V ( You may use 3 AA 1.5V Batteries)
• Size: 52 x 55 x 1.6 mm
• Weight: Approx 25g

Features:

• 0.44 inch clock use special red digital tube display;
• Import AT89C2051 as main control chip;
• 1.6 mm thick PCB made by military level FR - 4 plates, the most thick plate
• Few components, installation is simple, high success rate, don't debugging
• As accurate, as error range in 3 seconds.