WELCOME TO THE TEAM PAGE
Links to team members' pages
PROJECT DESCRIPTION
The project is the design and implementation of a large 7-segment display system that serves as a 12 hour clock, which displays the current time, including seconds and indicates whether AM or PM. The key components of this project involve the utilization of decade counter integrated circuits (ICs) to accurately keep track of time and control the display. The primary goal is to create a clock with frequency of 1Hz, maintaining a reasonable degree of accuracy.
The following requirements were considered:
- The display must be large and legible from a considerable distance, allowing easy visibility from up to 100 meters away.
- The clock should be capable of operating from mains power, ensuring a stable and reliable power source.
- Users should be able to adjust the time to reflect the accurate time as needed.
- An LED activates every 15 minutes for 3 seconds.
- To add some complexity to the project, we designed a 12-hour clock.
Components used:
- 74175 - D flip flop SN74LS175N
- 7404 - NOT gate SN74LS04N
- 7408 - AND gate SN7408N
- 7447 - BCD to 7 segment decoder SN74LS47N
- 7411 - 3 input and gate
- 7432 - 2 input or gate
- 74193 - up/down counter
- 74192 - decade counter
- 7420 - 4 input NAND gate
- 7400 -2 input NAND gate
- NE555 timer
- 100k resistors
- Push buttons
- LM7805 voltage regulator
- 1N4007 diodes
- 470uF capacitor
- 0.1uF capacitor
- 230-15V Step Down Transformer
HOW IT OPERATES
The device is asynchronous. It uses 2 each decade counters to keep track of the minutes and seconds. The four 4-bit outputs of these decade counters are fed into 4 BCD to 7 segment displays to show their digits. The hours are handled by a single hex counter which counts from 1 to 12. The 4-bit output of this hex counter is converted to its corresponding two-digit number, each digit represented by a 4-bit binary number. This conversion is done using some AND-OR logic. The two 4-bit outputs of this are also fed into 2 BCD to 7 segment display to display the hour digits. The device keeps track of AM or PM by using a D flip-flop.
IMAGES OF OUR FILES
Logisim schematic
EasyEDA schematic
PCB design for the main circuit
2D PCB design for the main circuit
EasyEDA schematic design for the seven segment
PCB design for the seven segment
