Density Based Traffic Light Controlleing Using Arduino

you are going to learn about how to make an density based traffic light controller using Arduino. The main purpose of this project is, if there will be no traffic on the other signal, one shouldn’t wait for that signal. The system will skip that signal and will move on the next one.

Video :-

The working of the project is divided into three steps

• If there is traffic at all the signals, then the system will work normally by controlling the signals one by one.
• If there is no traffic near a signal, then the system will skip this signal and will move on to the next one. For example, if there is no vehicle at signal 2, 3 and currently the system is allowing vehicles at signal 1 to pass. Then after signal 1, the system will move on to signal 4 skipping signal 2 and 3.
• If there is no traffic at all the 4 signals, system will stop at the current signal and will only move on the next signal if there will be traffic at any other signal.

Circuit Diagram :-

Code :-

//Prateek //www.prateeks.in #include<TimerOne.h> int signal1[] = {23, 25, 27}; int signal2[] = {46, 48, 50}; int signal3[] = {13, 12, 11}; int signal4[] = {10, 9, 8}; int redDelay = 5000; int yellowDelay = 2000; volatile int triggerpin1 = 31; volatile int echopin1 = 29; volatile int triggerpin2 = 44; volatile int echopin2 = 42; volatile int triggerpin3 = 7; volatile int echopin3 = 6; volatile int triggerpin4 = 5; volatile int echopin4 = 4; volatile long time; // Variable for storing the time traveled volatile int S1, S2, S3, S4; // Variables for storing the distance covered int t = 5; // distance under which it will look for vehicles. void setup(){ Serial.begin(115200); Timer1.initialize(100000); //Begin using the timer. This function must be called first. "microseconds" is the period of time the timer takes. Timer1.attachInterrupt(softInterr); //Run a function each time the timer period finishes. // Declaring LED pins as output for(int i=0; i<3; i++){ pinMode(signal1[i], OUTPUT); pinMode(signal2[i], OUTPUT); pinMode(signal3[i], OUTPUT); pinMode(signal4[i], OUTPUT); } // Declaring ultrasonic sensor pins as output pinMode(triggerpin1, OUTPUT); pinMode(echopin1, INPUT); pinMode(triggerpin2, OUTPUT); pinMode(echopin2, INPUT); pinMode(triggerpin3, OUTPUT); pinMode(echopin3, INPUT); pinMode(triggerpin4, OUTPUT); pinMode(echopin4, INPUT); } void loop() { // If there are vehicles at signal 1 if(S1<t) { signal1Function(); } // If there are vehicles at signal 2 if(S2<t) { signal2Function(); } // If there are vehicles at signal 3 if(S3<t) { signal3Function(); } // If there are vehicles at signal 4 if(S4<t) { signal4Function(); } } // This is interrupt function and it will run each time the timer period finishes. The timer period is set at 100 milli seconds. void softInterr() { // Reading from first ultrasonic sensor digitalWrite(triggerpin1, LOW); delayMicroseconds(2); digitalWrite(triggerpin1, HIGH); delayMicroseconds(10); digitalWrite(triggerpin1, LOW); time = pulseIn(echopin1, HIGH); S1= time*0.034/2; // Reading from second ultrasonic sensor digitalWrite(triggerpin2, LOW); delayMicroseconds(2); digitalWrite(triggerpin2, HIGH); delayMicroseconds(10); digitalWrite(triggerpin2, LOW); time = pulseIn(echopin2, HIGH); S2= time*0.034/2; // Reading from third ultrasonic sensor digitalWrite(triggerpin3, LOW); delayMicroseconds(2); digitalWrite(triggerpin3, HIGH); delayMicroseconds(10); digitalWrite(triggerpin3, LOW); time = pulseIn(echopin3, HIGH); S3= time*0.034/2; // Reading from fourth ultrasonic sensor digitalWrite(triggerpin4, LOW); delayMicroseconds(2); digitalWrite(triggerpin4, HIGH); delayMicroseconds(10); digitalWrite(triggerpin4, LOW); time = pulseIn(echopin4, HIGH); S4= time*0.034/2; // Print distance values on serial monitor for debugging Serial.print("S1: "); Serial.print(S1); Serial.print(" S2: "); Serial.print(S2); Serial.print(" S3: "); Serial.print(S3); Serial.print(" S4: "); Serial.println(S4); } void signal1Function() { Serial.println("1"); low(); // Make RED LED LOW and make Green HIGH for 5 seconds digitalWrite(signal1[0], LOW); digitalWrite(signal1[2], HIGH); delay(redDelay); // if there are vehicels at other signals if(S2<t || S3<t || S4<t) { // Make Green LED LOW and make yellow LED HIGH for 2 seconds digitalWrite(signal1[2], LOW); digitalWrite(signal1[1], HIGH); delay(yellowDelay); } } void signal2Function() { Serial.println("2"); low(); digitalWrite(signal2[0], LOW); digitalWrite(signal2[2], HIGH); delay(redDelay); if(S1<t || S3<t || S4<t) { digitalWrite(signal2[2], LOW); digitalWrite(signal2[1], HIGH); delay(yellowDelay); } } void signal3Function() { Serial.println("3"); low(); digitalWrite(signal3[0], LOW); digitalWrite(signal3[2], HIGH); delay(redDelay); if(S1<t || S2<t || S4<t) { digitalWrite(signal3[2], LOW); digitalWrite(signal3[1], HIGH); delay(yellowDelay); } } void signal4Function() { Serial.println("4"); low(); digitalWrite(signal4[0], LOW); digitalWrite(signal4[2], HIGH); delay(redDelay); if(S1<t || S2<t || S3<t) { digitalWrite(signal4[2], LOW); digitalWrite(signal4[1], HIGH); delay(yellowDelay); } } // Function to make all LED's LOW except RED one's. void low() { for(int i=1; i<3; i++) { digitalWrite(signal1[i], LOW); digitalWrite(signal2[i], LOW); digitalWrite(signal3[i], LOW); digitalWrite(signal4[i], LOW); } for(int i=0; i<1; i++) { digitalWrite(signal1[i], HIGH); digitalWrite(signal2[i], HIGH); digitalWrite(signal3[i], HIGH); digitalWrite(signal4[i], HIGH); } }