Design of a Digital Clock

The aim of this project is to apply concepts learned from Digital Systems Design in designing a Digital Clock Circuit. The components used were:

• Resistors
• Capacitors
• AND Gates
• OR Gates
• NOT Gates
• Seven Segment Displays
• BCD to Seven Segment Display Driver
• Swicthes
• AND Gates
• NE555 Timer
• 6 × Modulo-15 Counters
• D flip flop
• LEDs
• Transformer
• Connector
• Bridge Rectifier
• Voltage Regulator LM7805

Our circuit comprises an NE555 timer generating the clock signal, which is directed to a BCD 74161 modulo-15 counter managing the seconds. Upon receiving 10 clock pulses, this counter triggers the 74161 IC handling the tens of seconds, with a constraint to prevent exceeding 60 seconds by resetting at six counts. The tens of seconds counter further relays a clock signal to the minute section, operating similarly to the seconds counter. For the hour section, the clock signal is sourced from the 10s of minutes 74161 IC. Due to the clock's 12-hour format, it cycles from 0 to 12. A buzzer activates every 15 minutes for one minute. To set the time, a switch initiates the clock signal's movement through the counter ICs, increasing both the hours and minutes by a second during the setting process. Lastly, a D flip-flop uses LEDs to indicate whether it's AM or PM, displaying the time of day. Below is the PCB schematic.