IR Beacon and Locator

In robotics class, we are building robots that can find “packages” (a cube with an IR LED in it) and return them to a drop zone. To make the drop zone find-able by the robot, we would like to use an IR beacon. To make the drop zone distinguishable from the package, I’m assuming we can make the IR at the drop zone flash a unique code (using an arduino) and have the robot look for that code once it has a package. The package IR LED is a steady-on.
Is this the right approach? If so, what would the code for the beacon look like? How about the code to find the beacon?

Thanks!

Might be easier just to flash two frequencies and have two receivers. http://www.digikey.com/product-search/en/sensors-transducers/optical-sensors-photo-detectors-remote-receiver/1967024

The package IR LED is a steady-on.

Might be better to flash the beacon at 38khz so an IR detector module can be used for the detector. TV IR remote control stuff.

That is what we were thinking, but can we do that with only phototransistors (like these) and IR LEDs (like these)? We also have the 3-pin detectors (like these).

We aren't in a place to purchase anything new, so is there a way to do this with just these materials? I'm a novice at this, so any guidance would be helpful.

Your “3-pin detectors” should work just fine.

See: A Multi-Protocol Infrared Remote Library for the Arduino

For your beacon you’ll need a separate Arduino running the IR library and blinking an IR LED using pretty much any remote control code. Then on your mobile robot, also with the IR library loaded, when the three-pin detector sees a valid code coming in then you’ll know that your detector is facing that beacon. You’ll want to add some kind of shroud to the detector to make it directional, of course.