Digital Counter for Car Parking System
Objectives:
The objective of this assignment is to design and construct a car park digital controller circuit for 99 car parking slots using sequential and combinational logic circuits. The circuits will receive the digital signals from two sensors located at the ENTRANCE and EXIT of the car park to display the number of empty slots and to display the word FULL in case of no more empty slots.
Introduction:
We need to monitor the number of empty slots in the parking areas by setting up a sensor EN allocated in the ENTRANCE whereas the output of this sensor is HIGH (1) when there is a car entering the parking area. On the other hand, EX is allocated in the EXIT; the output of this sensor is HIGH (1) when there is a car leaving the parking areas. Hence, both of the sensors are connected to a sequential digital circuit for which we call it an up-down counter for which the circuit is used to count the number of cars entering and exiting the parking areas; the output of this circuit is connected to the 7-segments decoder to convert each BCD code to ten possible number from 0 to 9 in order display the number of empty slots available and to display the word FULL when there are no empty parking slots available as shown below:
7-Segments
Driver
EN
Counter
Decoder
Counter
EX
Counter
The 7-segments display board
Figure 1: Processes involved in displaying number of empty slots available and ‘FULL’
Design Procedure: 1. Synchronous BCD Up -down Counter
Conditions:
* One BCD up-down counter only responsible to count from 0 to 9. In order to count from 00 to 99, we then need to cascade two BCD up-down counters together. * The counter can enable either the top counting mode or the down counting mode between the numbers lies between two limits of 00 to 99. * The minimum count that this circuit can count down to is 00; the maximum count is 99. * The output of the counter is display in binary code and in order to show that we then need to add
The objective of this assignment is to design and construct a car park digital controller circuit for 99 car parking slots using sequential and combinational logic circuits. The circuits will receive the digital signals from two sensors located at the ENTRANCE and EXIT of the car park to display the number of empty slots and to display the word FULL in case of no more empty slots.
Introduction:
We need to monitor the number of empty slots in the parking areas by setting up a sensor EN allocated in the ENTRANCE whereas the output of this sensor is HIGH (1) when there is a car entering the parking area. On the other hand, EX is allocated in the EXIT; the output of this sensor is HIGH (1) when there is a car leaving the parking areas. Hence, both of the sensors are connected to a sequential digital circuit for which we call it an up-down counter for which the circuit is used to count the number of cars entering and exiting the parking areas; the output of this circuit is connected to the 7-segments decoder to convert each BCD code to ten possible number from 0 to 9 in order display the number of empty slots available and to display the word FULL when there are no empty parking slots available as shown below:
7-Segments
Driver
EN
Counter
Decoder
Counter
EX
Counter
The 7-segments display board
Figure 1: Processes involved in displaying number of empty slots available and ‘FULL’
Design Procedure: 1. Synchronous BCD Up -down Counter
Conditions:
* One BCD up-down counter only responsible to count from 0 to 9. In order to count from 00 to 99, we then need to cascade two BCD up-down counters together. * The counter can enable either the top counting mode or the down counting mode between the numbers lies between two limits of 00 to 99. * The minimum count that this circuit can count down to is 00; the maximum count is 99. * The output of the counter is display in binary code and in order to show that we then need to add
Bibliography: 1. Floyd, Thomas L. , 2006, Digital Fundamentals: Ninth Edition, New Jersey, USA, Pearson Prentice Hall 2. Doctronic, "BCD Up/down counter." Beastie Zone. 1999. Doctronic Educational Publication. <http://www.doctronics.co.uk/beastie_zone.htm> [Accessed: 2 Mar 2009] 3. Doctronic, "BCD to seven segment decoder." Beastie Zone. 1999. Doctronic Educational Publication. <http://www.doctronics.co.uk/4511.htm> [Accessed: 2 Mar 2009] Ken Bijelow, "The Seven-Segment LED." Welcome to Play-Hookey websites. 2007. Doctronic Educational Publication. [Accessed: 2 Mar 2009] <http://www.play-hookey.com/digital/experiments/seven_seg_led.html>