IR photodiode and IR LED

how i can get the source code about the IR photodiode and IR LED ? thank you...

Start by explaining what you want to do with them.

i wan design a traffic light system.There will be a transmitter – receiver placed on both sides of the road. This transmitter continuously keeps transmitting IR pulse would either reach the receiver or shall be blocked by the vehicle if it is in-between. Based on this there shall be an increment in green light timings of the traffic light.

Then you can start by making a "photogate". Google "arduino ir photogate" for lots of ideas.

thank you ah^^