Very little external circuitry is required for IR communication. Ken Shirriff provides a good reference circuit for use with his own IRremote library. The only major caveat to using his topology is with regards to the default choice of I/O pins (see section Hardware/Pinout Selection). Given all this good work, please visit Ken's IRremote page for the wiring diagram.
- IRremote (Ken Shirriff): http://www.righto.com/2009/08/multi-protocol-infrared-remote-library.html
Similarly, a wiring diagram for the push button signal required by the ir_tx_onbutton sketch can be found on Ken's record/playback project page (again, see section Hardware/Pinout Selection for default pinout):
- Record/playback project (Ken Shirriff): http://www.righto.com/2009/09/arduino-universal-remote-record-and.html
The ir_messaging library is relatively flexible. The IR receiver software can be configured to listen on any available pin. However, the transmitter output pin is controlled by whatever timer generates the output carrier:
- ATmega328/328P
- Timer2 ⇒ Pin 3.
- ATmega1280/2560
- Timer1 ⇒ Pin 11.
- Timer2 ⇒ Pin 9.
- Timer3 ⇒ Pin 5.
- Timer4 ⇒ Pin 6.
Please refer to the appropriate datasheet for more details regarding the capabilities of your particular Arduino platform.