Turns on LED upon receiving IR signal

[DutCampos]

Hi everyone, I'm working on what I think is a fairly simple project. However, I have no previous experience with electronics, so help would be greatly appreciated.

I have to build two pairs of circuits: an IR transmitter and an IR receiver for each (let's call them pair A and pair B). The IR receiver needs to receive a signal from the transmitter and, upon receiving it, turn on a visible light LED (color doesn't really matter).

The two catches are: 1) The pairs need to be "unique", meaning that Receiver A can't light up upon receivipng a signal from transmitter B (I think this means I need to modulate the transmitter's carrier frequency). And 2) I need them to be as small as I can possibly make it, especially the receiver.

Here are some ideas, from what I've read:

Feel free to disregard all of this if it's stupid or if you have a better idea!!

a) The receiver would use something like this (https://www.sparkfun.com/datasheets/Sen ... sop382.pdf) of two different carrier frequencies. I would use that to light up a regular LED with a small button-cell battery.
b) I could use this (https://www.sparkfun.com/datasheets/Com ... DS1077.pdf) to modulate the carrier frequency on the transmitter, maybe?
c) Build the receiver circuit on this protoboard (https://www.sparkfun.com/products/8886)

Ask me if you have any questions and thank you for your help!