User manual

control air conditioners and fans however protocols used for air-conditioners are extremely difficult

to implement and we have not directly supported such protocols because they are very rare.

Typically the output pin of an Arduino cannot supply sufficient current to drive and IR LED so you will

want to implement a simple driver circuit using NPN transistor and a 470 ohm resistor is shown

here:

Make sure that you get the polarity of the LED correct. The shorter of the two leads connects to the

transistor and the longer one connects to the positive supply. Note that the current passing through

the LED will in all likelihood will exceed the maximum continuous current rating. However because

the signal is modulated and sending a sequence of pulses that will only last a few milliseconds the

circuit will work fine.

More advanced driver circuit schematics are available in the IRLib manual in section 1.4 Hardware

Considerations.