Using Millis() instead of delay() with neopixel and ir shar!

Hello everyone!

I am using gsr sensor, a neopixel strip, and a ir sharp sensor.
There are three main steps:

  1. The led is off, when the user put his finger on the gsr sensor the led start fading and blinking. --> WORK
  2. When a certain value is detected by GSR the led stops blinking and start spinning. --> WORK
  3. While the led is spinning the ir sensor should detect if someone is passing by and updates a counter. --> NOT WORKING

I have put a delay() in the ir sensor because otherwise it detects more than one passage at a time. The delay() obviously stop all the program including the led strip. I have tried to use the Millis( ) function but without success.
Here the code

#include <Adafruit_NeoPixel.h>
#define PIN 2
#define NUM_PIXELS 146
Adafruit_NeoPixel strip(NUM_PIXELS, PIN, NEO_GRB + NEO_KHZ800);
const int GSR = A0;
int threshold = 0;
int sensorValue;
int emozione[6];
int delta;
int giri;
int ir_pin = 5;
int hitObject = false;
long sum = 0;
bool lockout = false; //to print the sensor value only when the fingers are placed
bool luce = false; // to change the status of the light

unsigned long previousMillis = 0;
const long interval = 1000;

void setup() {
  strip.begin();
  strip.show();
  Serial.begin(9600);
  pinMode(ir_pin, INPUT); //counter inoput
  delay(1000);
}

void loop() {
  sensorValue = analogRead(GSR);

  if (sensorValue > 400) { //when the fingers are not resting the treshold is reset
    sum = 0;
  }

  if (luce == false && sensorValue < 400) { //if the light is off and the fingers are resting it starts to throb
    GetTreshold(); //get the resting conductivity of the utent
    FadeInOut(0xff, 0x77, 0x00); //the light pulses and the user's emotion is monitored
  }

  if (luce == true && giri > 0) { // when an emotion is detected (and therefore the number of giri he has to do) the light pulses
    for (int i = 0; i < NUM_PIXELS; i++) {
      unsigned long currentMillis = millis();
      if (currentMillis - previousMillis >= interval) {
        // save the last time you blinked the LED
        previousMillis = currentMillis;
        CounterGiri(); // monitor the user's circumambulation around the object
      }
      strip.setPixelColor(i, 0xff, 0x77, 0x00);
      strip.setPixelColor(i - 1, 0xff, 0x77, 0x00);
      //     strip.setPixelColor(i - 2,  0xff, 0x77, 0x00);
      strip.show();
      delay(20);
      strip.clear();
    }
  }
}

void GetTreshold() { // determines the teshold, the base value on which to calculate the delta
  if (sum == 0) {
    delay (1000);
    for (int i = 0; i < 700; i++) { // average between 500 values ​​to have a treshold
      sensorValue = analogRead(GSR);
      sum += sensorValue;
      delay(5);
    }
    threshold = sum / 700;
    Serial.print("threshold =");
    Serial.println(threshold);
  }
}

void ReadValue() {
  sensorValue = analogRead(GSR);
  Serial.print("sensorValue=");
  Serial.println(sensorValue);
  delay(10);
  delta = threshold - sensorValue;
  if (delta > 20 && luce == false) { //if the difference between treshold and detected value is greater than a tot, an emotion is recorded
    printemotion();
  }
}

void printemotion() {
  Serial.println("EMOZIONE RILEVATA!");
  for (int i = 0; i < 6; i++) {  //save the 6 values ​​following the detection of the emotion to approach the minimum of the peak
    sensorValue = analogRead(GSR);
    emozione[i] = sensorValue - threshold;
    delay(200);
  }
  Serial.println(abs(emozione[5]));
  lockout = true;
  giri = abs(emozione[5]) - 20; //return the number of turns (giri)
  Serial.print("emozione =");
  Serial.println(giri);
  luce = true;  //change the state of the light which stops pulsing and starts spinning
  delay (3000); //time between when the light stops pulsing and starts spinning
}

void FadeInOut(byte red, byte green, byte blue) {
  float r, g, b;
  for (int k = 0; k < 256; k = k + 2) {
    ReadValue();
    r = (k / 256.0) * red;
    g = (k / 256.0) * green;
    b = (k / 256.0) * blue;
    setAll(r, g, b);
    strip.show();
  }
  for (int k = 255; k >= (-1); k = k - 4) {
    ReadValue();
    r = (k / 256.0) * red;
    g = (k / 256.0) * green;
    b = (k / 256.0) * blue;
    setAll(r, g, b);
    strip.show();
  }
}


void setPixel(int Pixel, byte red, byte green, byte blue) {
  strip.setPixelColor(Pixel, strip.Color(red, green, blue));
}

void setAll(byte red, byte green, byte blue) {
  for (int i = 0; i < NUM_PIXELS; i++ ) {
    setPixel(i, red, green, blue);
  }
  strip.show();
}


void CounterGiri() {
  int val = digitalRead(ir_pin);
  if ( (val == 0) && (hitObject == false) && giri > 0 ) {
    giri--;
    hitObject = true;
    Serial.print("Giri = ");
    Serial.println( giri);
    //delay (500); //trying not to use it because it stops the spin o the led too
  }
  else if ( (val == 1) && (hitObject == true) ) {
    hitObject = false;
  }
  if (giri == 0) {
    strip.clear();
  }
}

Thank you!

    Serial.print("Giri = ");

What do you see on the Serial output when you run the program? Please cut and paste the output, not a verbal description.

threshold =267
sensorValue=261
sensorValue=256
sensorValue=255
sensorValue=246
EMOZIONE RILEVATA!
10
emozione =10
sensorValue=501
sensorValue=502
sensorValue=502
sensorValue=578
Giri = 9

This. I have deleted most of sensor value to reduce the list.
After the emotion is detected there are some other sensor value from gsr because the led need to end the for.
"Giri = 9" is the first output given from the function CounterGiri( ).
There are not other because the ir does not detect my hand passing in front of it.