This is by far the longest-range UHF link ever described in SILICON CHIP - over 1km according to Oatley Electronics (the project's developers). It's also by far the easiest to build, thanks to pre-built UHF transmitter and receiver modules.

There are lots of things you could use this 433MHz UHF remote control unit for. Both the transmitter and receiver are smaller than a match box, making it suitable as a hand-held remote control for alarm systems, garage doors and electric door strikers. It can also be used for controlling pumps and gates (eg, on a small farm) and for remote data collection.

It all depends on the circuitry you "hang off" the four outputs on the receiver PC board.

A feature of the transmitter is its four separate pushbutton switches --one for each channel. However, depending on your application, these could be removed and replaced with a cable carrying data from a PC or some other device capable of generating 5V logic signals.

Note too that the transmitter will accept single or simultaneous button presses, or even BCD data. So, by connecting a suitable decoding chip to the receiver, you could control up to 16 separate outputs. For example, you could use a 4514 4-to-16 line decoder for controlling up to 16 outputs or a 4028 BCD-to-decimal decoder for controlling up to 10 outputs.