These days RF capabilities are present in almost all embeded applications and by RF i mean wireless transmission of data. The receiver and transmitter boards (RLP & TLP 315) for this project are cheap RF modules manufactured by Laipac Technologies. The frequency on which the receiver and transmitter pair works is 315 MHz, UHF (Ultra High Frequency) frequency range. The transmitter works from 2 V to 12 V and the receiver from 3.3 V to 6 V, the author supplied it with 5v in his circuit.
DIY Wireless receiver and transmitter: [Link]