In both the RoboSapien and the Roboquad project, I used an IR transmitter consisting of a Picaxe driving an IR LED. The IR transmitter used the appropriate control sequences for each robot. The IR transmitter had limited range, which limited its utility!
Thanks to Dr. Acula from the Picaxe forum I used this improved IR transmitter circuit. I boosted the current to the IR LED to over 1 Amp. Here is a schematic courtesy of Dr. Acula.
Here is a picture of the IR LED in operation.
