As some of you might have noticed, I've been gone for a while. I've been playing a lot of Airsoft recently and I thought up an idea, but I'm not sure how expencive/difficult this project would be. We usally play Free-for-all, Team Deathmatch, and Capture the Flag. But I thought of a way to play Control the Areas. Now here is where my question comes in. Is there a way to make a devices that will send a signal to a host device easily? This is my plan:

The Transmiter would send a signal to the Reciever when the switch is slid to one side, lighting up the corisponding LEDs. When an LED lights up on the Reciever, it adds 1 to the LED counter of that color. My question is how would you transmit the signal to the Reciever?