RC Transmitter / Receiver Question

[Longhair]

I want to do some basic things like turn on/off LEDs from a spare channel that is not in use. What I have done was just take a part a servo, removed the motor and soldered a couple of wires on the board for a basic switch. Simple enough...

One of the reasons for myself to get into electronics is to be able to do more than turn on/off LEDs - say have high/low/off  LEDs. I could just add some different value resistors and adjust the trim settings on the radio. Actually I have and it has been a hit & miss but still in the end, the results were there, just not perfect. That is fine if there is only 1 set of lights and 1 spare channel, but the problem lies when there is a need for 2 independently controlled lights (one low, one off / both low / one low, one high /  etc.) and there is only 1 spare channel.

What area should I be learning or what is it generally called? I am just talking about from the receiver to the device, not from the radio to the receiver.

[DaveW]

The easiest way to do this, and the most flexible if you want to be able to modify/expand later would to use a microcontroller-you can feed an R/C signal in, measure the length and then do almost anything depending on the signal. Switching can be done using the standard I/O, you can dim a LED with 256 levels of control using PWM, which can be expanded into motor control etc; almost anything you'd want to do for R/C.
Used to recommend the PICAXE chips for learning, but the arduino development systems are fantastic and loads of support & code around. In your case, the pulsein command would give you the length of the pulse and is already written for you. Something like the lilypad board would probably be powerful enough for most of these applications and is nice and light
http://arduino.cc/en/Reference/PulseIn
http://arduino.cc/en/Main/Hardware

[Jimmy]

I have done this with rgb led using 1 wire serial rx to another micro it is easy I had 1 transmitter and 8 recivers


http://www.sparkfun.com/datasheets/RF/KLP_Walkthrough.pdf