Arduino onboard LED pin number as a constant To use the onboard LED on an Arduino one usually has to know the pin number (13 in most cases), but is there a constant in the Arduino IDE one can use as well? 

So is it possible to use something like int LED = ONBOARDLED; instead of using int LED = 13;?
Try LED_BUILTIN:

pins_arduino.h:static const uint8_t LED_BUILTIN = 13;