There are two main types of security beams on the market. Infra
red sensors and Infra red Point to Point Laser Beams
I have previously sold and installed infra red sensors that go on driveways. These are available from numerous outlets and mail order/magazine type suppliers. I stopped doing so due to constant customer feedback stating that were very "hit and miss". The reason being, is that the sensors are looking for heat, and this is not easy to detect on some vehicles. Also, they are limited if you have a stock paddock opposite the area you need to cover. If I had $1 for every time I have been to a place where this type of beam has failed and the owners have given up, I would be well on the way to retiring. Many people selling them work on the theory that not every one buying them will complain or want their money back, so make good money from fresh sales to customers who have not been burnt.
Therefore, I moved to selling only hardwired twin laser beams (often called POINT TO POINT BEAMS), which are a purpose built security product. As they are looking for a break in the beam, heat is irrelevant. There is a unit on each side of the drive, so stock paddocks do not become a problem. The only drawback with these was, a wire had to be run from the house to the drive, and then under the drive to the other side. It was however worth doing this where appropriate, for the hassle free operation that the hard wired beams give.
NZ MADE WIRELESS POINT TO POINT PARABEAM for when quality counts
As pictured above the same type of twin/dual laser beam are now available in a solar powered wireless model. They have proven to be excellent, I have some installed on my own drive and would not be without them. They have two way communication, many accessories such as pocket pagers and SMS texting devices, and best of all they are weather tight.