Arduino ir repeaters

Goal is to replace ir emitter led on a ac remote control by a photocoupler. This photocoupler will be then connected to arduino uno then decode receive ir command and send back news modify signal from arduino by ir emitter led to the ac units.

Will need help to create hand draw schematic of arduino connection
Then I will need arduino code to be able to create the list of commande normally send to be able to create instructions for final code of commande that need to be send when command are receive by photocoupler