RFID to Control LED

[gcjr]

@red_car

  if (onLED && millis() > onTime + MAX_ON_TIME)  
  {
    onLED = false;

in place of onLED, just read the pin -- digitalRead (LED) (this is fine unless performance becomes critical

@red_car

if (uid[0] == 0x33 && uid[1] == 0x06 && uid[2] == 0x64 && uid[3] == 0x97) 

what happens when you want to check for a different RFID

suggest having a comparison routine that compares 2 UIDs, return whether they match

@red_car

          if (onLED) // Already on, so turn off.
          {
            onLED = false;
            onTime = 0;
            digitalWrite(LED, LOW);
          }
          else // Already off, so turn on.
          {
            onLED = true;
            onTime = millis();
            digitalWrite(LED, HIGH);
          }

all of above amounts to just toggling the led

digitalWrite (LED, ! digitalRead (LED));

onTIme can always be set to millis() if digitalRead (LED) is used to check whether it needs to be turned off