On/Off switch with button on arduino - arduino

Question

I'm trying to create an Arduino circuit which runs this code. Basically, whith an ultrasonic sensor module, I set different distance ranges.
Within every range I chose to play a buzzer and light up a RGB led with different combinations.
Everything worked so far until I decided to add a button to act as a switch:
I can't think of a code that "turnes on/off" the circuit. To be more specific I want to light up a led (pin n.11) if the circuit is off, and to work normally when it's on, but now it works in the "on" state only if I keep pressed the button, and if I release it, the circuit "locks itself" on the last set of frequency (for the buzzer) and color (for the RGB led).
//pins for buzzer and ultrasonic sensor
int const trigPin = 10;
int const echoPin = 9;
int const buzzPin = 2;
//pins for rgb led(color changes as i get closer to an object)
const int VERDE = 3;
const int BLU = 5;
const int ROSSO = 6;
//pin for led representing main state of the circuit
const int accPin = 7;
// pins for button i want to use as an on/off switch
const int buttonPin = 11;
int stato=0;
int old = 0;
const int delayTime = 5;
void setup()
{
pinMode(VERDE, OUTPUT);
pinMode(BLU, OUTPUT);
pinMode(ROSSO, OUTPUT);
pinMode(accPin,OUTPUT);
digitalWrite(VERDE, LOW);
digitalWrite(BLU, LOW);
digitalWrite(ROSSO, LOW);
digitalWrite(accPin,LOW);
pinMode(buttonPin,INPUT);
pinMode(trigPin, OUTPUT); // trig pin will have pulses output
pinMode(echoPin, INPUT); // echo pin should be input to get pulse width
pinMode(buzzPin, OUTPUT); // buzz pin is output to control buzzering
}
void loop(){
stato=digitalRead(buttonPin);
//if the circuit is off and i turn it on by pressing the button, or if the circuit's already on, then do the things
if(((stato==1)&&(old==0))||((stato==0)&&(old==1))){
digitalWrite(accPin,LOW);
int duration, distance; // Duration will be the input pulse width and distance will be the distance to the obstacle in centimeters
digitalWrite(trigPin, HIGH); // Output pulse with 1ms width on trigPin
delay(1);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH); // Measure the pulse input in echo pin
// Distance is half the duration devided by 29.1 (from datasheet)
distance = (duration/2) / 29.1;
// the following code is just a test to see get a different frequency from the buzzer and a different color from the rgb led, while moving from the facing object
if (distance <= 10 && distance >= 0) {
// Buzz
tone(buzzPin, 2000);
digitalWrite(ROSSO, HIGH);
}
if (distance <= 20 && distance > 10) {
// Buzz
tone(buzzPin, 1750);
digitalWrite(BLU, HIGH);
digitalWrite(ROSSO, HIGH);
}
if (distance <= 30 && distance > 20) {
// Buzz
tone(buzzPin, 1250);
digitalWrite(BLU, HIGH);
}
if (distance <= 40 && distance > 30) {
// Buzz
tone(buzzPin, 1000);
digitalWrite(BLU, HIGH);
digitalWrite(VERDE, HIGH);
}
if (distance <= 80 && distance > 50) {
// Buzz
tone(buzzPin, 750);
digitalWrite(VERDE, HIGH);
}
if(distance>=81){
noTone(buzzPin);// if out of range then shut up
}
delay(60); // Waiting 60 ms won't hurt any one
digitalWrite(VERDE, LOW);
digitalWrite(BLU, LOW);
digitalWrite(ROSSO, LOW);
old=1;
}
//if the circuit is on and i press the button, turn it off
if((old==1)&&(stato=1)){old=0;}
//if the circuit is off and if i let it like this, don't do nothing, but turn on the a led to make it obvious(pin n.11)
if((old==0)&&(stato==0)){
digitalWrite(VERDE, LOW);
digitalWrite(BLU, LOW);
digitalWrite(ROSSO, LOW);
noTone(buzzPin);
digitalWrite(accPin,HIGH);
}
}

Answer 1

Create a function with your whole code, or with piece that starts your process, than attach interrupt to the button pin (you'll have to replace the button pin). Use booleans to toggle button press.