Beginner Question: Blinking LED when sensor value = xyz / Loop?

Using Arduino Programming Questions
7

No, I was thinking of something much simpler: (uncompiled, untested)

const int SensorA = 0;
const int ledPin =  2;      // the number of the LED pin

int ledState = LOW;             // ledState used to set the LED
long previousMillis = 0;        // will store last time LED was updated
long interval = 1000;           // interval at which to blink (milliseconds)

void setup() 
{
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);      
}

void loop()
{
  int sensor_val = analogRead(SensorA);
  Serial.print("Value from sensor");
  Serial.println( sensor_val );

  if (sensor_val > 850){
    Serial.print("not enough");
    interval = 100;
  } else if ((sensor_val < 850) && (sensor_val > 500)) {
    Serial.print("good");
    interval = 500;
  }
  
  unsigned long currentMillis = millis();

  if(currentMillis - previousMillis > interval) {
    // save the last time you blinked the LED 
    previousMillis = currentMillis;   

    // if the LED is off turn it on and vice-versa:
    ledState = 1 - ledState;
    digitalWrite(ledPin, ledState);
  }
}

Not sure exactly what blink rate you want, but hopefully, you get the idea.