Unfortunately I have not been able to find anything reasonable online. I'd like an in depth all-inclusive explanation of IR transmitters and receivers, from a physical standpoint. I would also be glad to learn whatever else is included in the reading material, if anything. I have basic questions such as: how close does the IR receiver need to be to the transmitter, does it need to be within its 'line of sight,' will there be significant interference from visible light (I assume so, which is why I see shielding and modulation occurring), and how does it all work in the first place. I suppose the latter concept might be found in a semiconductor physics book, but I am not sure. Thank you very much.