Digital Desk Clock with 7-segment Display

Figure 1 

The digital desk clock project was created for displaying the time and date on ten 7-segment displays.

The project was built based on some requirements like the use of 7-segment displays, simultaneously displaying the time and date, time and date setting buttons, leap years handling, and fitting in a small red translucent box. Eight outputs are used by the circuit for the segments and decimal points including a 4-line to 10-line decoder for selecting the digit via a transistor. The displays are common anode so a port set low turns the segment ON and a port set high turns it OFF.

Two buttons are provided to allow the setting of time with the first button selecting the digit and the second increments the digits. The order of LEDs follows the Hours, Minutes, Day, Month, Year. Only the digits being set are displayed when the setting mode is active.

The segments for a digit are only ON while the digit is ON since each of the digits is turned ON sequentially. This process was implemented in order to avoid 80 outputs from powering each individual segment. A transistor powers each of the digits.

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