How to add the Interrupt(); function to arduino code - arduino

Question

For a small school project I am building a simulation of a traffic light system, based on three directions. What makes the system special is it can detect vehicles waiting in front of the traffic light. When a vehicle is detected, the given direction will get a green light. To do so I make use of a Hall Effect sensor.
Right now I am stuck on the following problem; the Arduino stops detecting the state of the sensor while giving a certain direction a green light. I already have read about the Interrupt() function to do certain tasks simultaneously but didn't manage to implement it in my code.
Hope you guys know a way to do so!
int sensorPin3 = 2;
int sensorPin2 = 3;
int sensorPin1 = 4;
int g1 = 11;
int y1 = 12;
int r1 = 13;
int g2 = 8;
int y2 = 9;
int r2 = 10;
int g3 = 5;
int y3 = 6;
int r3 = 7;
int counter = 0;
boolean sensorState1 = false;
boolean sensorState2 = false;
boolean sensorState3 = false;
void setup()
{
// setup serial - diagnostics - port
Serial.begin(9600);
pinMode(sensorPin1, INPUT);
pinMode(sensorPin2, INPUT);
pinMode(sensorPin3, INPUT);
digitalWrite(sensorPin1, HIGH);
digitalWrite(sensorPin2, HIGH);
digitalWrite(sensorPin3, HIGH);
pinMode(g1, OUTPUT);
pinMode(y1, OUTPUT);
pinMode(r1, OUTPUT);
pinMode(g2, OUTPUT);
pinMode(y2, OUTPUT);
pinMode(r2, OUTPUT);
pinMode(g3, OUTPUT);
pinMode(y3, OUTPUT);
pinMode(r3, OUTPUT);
}
void loop()
{
digitalWrite (r1, HIGH);
digitalWrite (r2, HIGH);
digitalWrite (r3, HIGH);
if(magnetPresent(sensorPin1) && !sensorState1)
{
sensorState1 = true;
}
else if(!magnetPresent(sensorPin1) && sensorState1)
{
if(sensorState1 = false);
Serial.println("detect1");
richting1();
}
if(magnetPresent(sensorPin2) && !sensorState2)
{
sensorState2 = true;
}
else if(!magnetPresent(sensorPin2) && sensorState2)
{
if (sensorState2 = false);
Serial.println("detect2");
richting2();
}
if(magnetPresent(sensorPin3) && !sensorState3)
{
sensorState3 = true;
}
else if(!magnetPresent(sensorPin3) && sensorState3)
{
if (sensorState3 = false);
Serial.println("detect3");
richting3();
}
}
void printMessage(String message){
counter++;
Serial.print(counter);
Serial.print(" ");
Serial.println(message);
}
boolean magnetPresent(int pin){
return digitalRead(pin) == LOW;
}
void richting1()
{
digitalWrite (r1, HIGH);
digitalWrite (r2, HIGH);
digitalWrite (r3, HIGH);
delay(2000);
digitalWrite (r1, LOW);
digitalWrite (r2, HIGH);
digitalWrite (r3, HIGH);
digitalWrite (g1, HIGH);
delay(10000);
digitalWrite (y1, HIGH);
digitalWrite (r2, HIGH);
digitalWrite (r3, HIGH);
digitalWrite (g1, LOW);
delay(2000);
digitalWrite (y1, LOW);
digitalWrite (r1, HIGH);
}
void richting2()
{
digitalWrite (r1, HIGH);
digitalWrite (r2, HIGH);
digitalWrite (r3, HIGH);
delay(2000);
digitalWrite (r2, LOW);
digitalWrite (r1, HIGH);
digitalWrite (r3, HIGH);
digitalWrite (g2, HIGH);
delay(10000);
digitalWrite (y2, HIGH);
digitalWrite (r1, HIGH);
digitalWrite (r3, HIGH);
digitalWrite (g2, LOW);
delay(2000);
digitalWrite (y2, LOW);
digitalWrite (r2, HIGH);
}
void richting3()
{
digitalWrite (r1, HIGH);
digitalWrite (r2, HIGH);
digitalWrite (r3, HIGH);
delay(2000);
digitalWrite (r3, LOW);
digitalWrite (y3, LOW);
digitalWrite (r1, HIGH);
digitalWrite (r2, HIGH);
digitalWrite (g3, HIGH);
delay(10000);
digitalWrite (y3, HIGH);
digitalWrite (r1, HIGH);
digitalWrite (r2, HIGH);
digitalWrite (g3, LOW);
delay(2000);
digitalWrite (y3, LOW);
digitalWrite (r3, HIGH);
}

Answer 1

#NickGammon made a great posts about interrupts and how to use them. It is more then complete so here is the link:
https://arduino.stackexchange.com/questions/30968/how-do-interrupts-work-on-the-arduino-uno-and-similar-boards
This is just a little opinion, but for traffic light codes, I found it a little simpler to make something like a custom delay. Take a look at this code and you'll hopefully understand it. Again, this was one of my school project in which I've used a template so you might see some useless crap in it!
/* This program acts like a pedestrian light. If the button is pressed, a light will turn on for a certain moment to let the person pass.
By : Dat HA
Date : 16/09/27
*/
//****************************** VARIABLES ******************************
const int leds[4][12] = //declaring leds - RED, YELLOW, GREEN
{
//R,Y,G,
{5, 6, 7}, //north
{8, 9, 10}, //east
{11, 12, 13}, //south
{2, 3, 4} //west
};
/* Sensors: sensorNumber - itemInArray - sensorDescription - pinDescription
1 - 0 - pushbutton
2 - 1 - photocell
3 - 2 - potentiometer
4 - 3 - distance - distanceEcho
5 - 4 - distance - distanceTrigger
6 - 5 - pushbutton (2)
7 - 6 - servo
*/
const int sensors[] = {A2, A7, A6, A4, A5, A3, A0}; //pin for each sensor
//****************************** SETUP ******************************
const int analogPins[6] = {A0, A1, A2, A3, A4, A5}; //for quick pinMode, distanceTrigger we be redeclared as an output is it is an analog input pin
void setup() {
for (int i = 2; i < 14; i++) //declaring digital pins as output for leds
{
pinMode(i, OUTPUT);
}
for (int i = 0; i < 6; i++) //declaring analog inputs
{
pinMode(analogPins[i], INPUT);
}
pinMode(sensors[4], OUTPUT); //declaring trigger pin as an output
}
//****************************** MAIN LOOP ******************************
int green = 5000;
int yellow = 3000;
int aa = 0;
void loop() {
//north, south
digitalWrite(leds[0][0], LOW); //red light off
digitalWrite(leds[2][0], LOW);
digitalWrite(leds[0][2], HIGH); //green light on
digitalWrite(leds[2][2], HIGH);
wait(green);
digitalWrite(leds[0][2], LOW); //green light off
digitalWrite(leds[2][2], LOW);
digitalWrite(leds[0][1], HIGH); //yellow light on
digitalWrite(leds[2][1], HIGH);
wait(yellow);
digitalWrite(leds[0][1], LOW); //yellow light off
digitalWrite(leds[2][1], LOW);
digitalWrite(leds[0][0], HIGH); //red light on
digitalWrite(leds[2][0], HIGH);
delay(100);
if (aa == 1)
{
flash();
}
//*************** SWITCHING SIDES ***************
digitalWrite(leds[1][0], LOW); //red light off
digitalWrite(leds[3][0], LOW);
digitalWrite(leds[1][2], HIGH); //green light on
digitalWrite(leds[3][2], HIGH);
wait(green);
digitalWrite(leds[1][2], LOW); //green light off
digitalWrite(leds[3][2], LOW);
digitalWrite(leds[1][1], HIGH); //yellow light on
digitalWrite(leds[3][1], HIGH);
wait(yellow);
digitalWrite(leds[1][1], LOW); //yellow light off
digitalWrite(leds[3][1], LOW);
digitalWrite(leds[1][0], HIGH); //red light on
digitalWrite(leds[3][0], HIGH);
delay(100);
if (aa == 1)
{
flash();
}
}
//****************************** FUNCTIONS ******************************
/* Usable functions list:
LEDS functions - do something to the leds
ledClear() turn all leds off
ledRedOn() turn all red leds on
ledYelOn() turn all yellow leds on
ledGreOn() turn all green leds on
SENSORS functions - they will return the apropriate value
pushButton() values: 0,1
photocell() values: 0-1023
potentiometer() values: 0-1023
distance() values: 0-200
*/
void ledClear() //turn off all leds
{
for (int i = 2; i < 14; i++)
{
digitalWrite(i, LOW); //turning leds off
}
}
void ledRedOn()
{
for (int i = 0; i < 4; i++)
{
digitalWrite(leds[i][0], HIGH); //turning red leds on
}
}
void ledRedOff()
{
for (int i = 0; i < 4; i++)
{
digitalWrite(leds[i][0], LOW); //turning red leds on
}
}
void ledYelOn()
{
for (int i = 0; i < 4; i++)
{
digitalWrite(leds[i][1], HIGH); //turning yellow leds on
}
}
void ledGreOn()
{
for (int i = 0; i < 4; i++)
{
digitalWrite(leds[i][2], HIGH); //turning green leds on
}
}
int pushButton() // sensor 1
{
int x = digitalRead(sensors[0]);
return x; //returning digital value of pushbutton which is either 0 or 1
}
void flash() //flash the red led
{
for (int i = 0; i < 12; i++)
{
ledGreOn();
ledRedOn(); //on
delay(200); //wait
ledRedOff(); //off
delay(200); //wait
}
ledClear();
aa = 0;
}
int wait(int x) //see if the wire is disconnected and if so, flash the red led
{
int i = 0;
unsigned long currentMillis = millis(); //current time
while (millis() - currentMillis <= x) //delay
{
if (digitalRead(A2) == HIGH) //if wire disconnected
{
aa = 1;
}
}
}