Why PIN3 stays at 1v3 in a IR emitter project?
A few things. As somebody else suggested, try a normal red LED and make sure that works first.

Note that your resistor is allowing too much current through the LED. A high-current LED might tolerate 20 mA (thousandths of an amp.) With a 47 ohm resistor, you're pumping 5/47, or about 106 mA into the LED, which is likely more than 5 times what it is designed to handle. You will quickly burn out your LED. You should use a 270 ohm resistor instead.

Also try just setting pin 3 to an output with this line:

pinMode(3, OUTPUT);


And then manually setting that pin to on:

digitalWrite(3, 1);


If the LED lights up, you know the pin is working correctly. Then use the code you posted with the same setup, and make sure your LED flashes. If THAT works, try putting your IR LED back in the circuit.