Four Way Traffic Signal Using Basic Logic Gates and Flip Flops

4 Way Traffic Signal Using Basic Logic Gates & Flip Flops

Due to increase in traffic, the user of vehicles are facing too much problems at roads. Sometimes the roads get block and the traffic flow is disturbed. Sometimes it leads to hazardous accident in which lot of people lose their lives. In order to control the flow of traffic, traffic signals are being implemented which helps in smooth flow of traffic. In big cities there are 8 lane traffic and 4 traffic signals people will find at the junction. The designing of 4 way traffic signal using logic gates & flip flops is totally based on the concepts that are covered in Digital Logic Design Course.

Components 

1. 4 bit counter (IC-7476 is being used for this purpose as T-flip flop)

2. Basic Gates (IC-7408,IC-7486,IC-7404,IC-7432)

3. Power Supply

4. Clock

5. Breadboard for circuit implementation

6. LED’s (Red, Green, Yellow).

7. Resistors (100 ohm)

4. 555 Timer IC

Basic Idea

The basic idea behind this design is to avoid the collision of vehicles by providing appropriate signals to different directions for a limited time slot, after which the next waiting drivers will be given same treatment. In this way, a cycle will be established which will control the traffic.

Control Signals

Each control signal contains 3 lights.

1. Top light is Red (Stop).

2. Middle light is Yellow (Wait).

3. Bottom light is Green (Go).

General Flow of Circuit

Timer --------> Counter -------->  Combinational logic

For timing purpose or pulse generation, 555 timer IC is being used. As the flip flops are synchronous circuit and clock is being used so we will use 555 timer as a pulse. 4 bit counter is designed and after it outputs for each signal are designed on the basis of time delay and other requirements.

Procedure

In order to design 4 way traffic using 4 bit counter, first it is advised to  design the truth table of 4 bit counter using T-flip flop. As T-flip flop is not readily available in market so by using IC – 7476 (JK- flip flop), T flip flop can be designed by shorting both ports of JK.

4 Bit Counter Truth Table using T-flip flops

The equations for each flip flop can be find by using K-Map. After the implementation of 4 bit counter, again design a truth table from which different outputs have to be taken according to the requirement. 

4 way traffic signal using Basic Logic Gates & T flip flop

Using K-Map, find the equations for each light signal. After finding the equations implement the equations by using basic logic gates and flip flops.

Implementation

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