They made stump Cam (Stump camera) in the early eighties. then cricket coverage saw Snikometer in nineties with Speed Gun in 1999. Channel 9 network were not satisfied, so they made Hawkeye in 2002.
No one said Nine Network will sleep now, & neither they did. Come Ashes
2006, Channel 9 (must in Australia, famous worldwide TV network) came up with yet another new technology called "Hot Spot". The idea is to have two infra-red cameras static above the the field of cricket arena & contineously record the play. One edge or snick, bat-pad appeal is followed by feeding that Infra red camera recording into Computers which in turn show the negative image of the incident just happened. What it does, is shows the point where the ball hit the batsman. Heat being produced due to friction is nothing new, so these camera's catch whatever small heat they find, to show it on negative images.
Ultimately, we know where the ball hit the batsman, if at all the bat. They say this technology is commonly used by Military to track Jet fighter planes & tanks. They also claim it's 100% accurate to tell the ball has hit the bat, pad, glove or only ground.
Doing some googling, I found that this technology was originally found by French scientiest Nicholas Bion, before being worked upon by several companies in Paris. In fact, Channel 9 has admitted to have brought the equipment for Ashes 2006 series from Paris after working on it themselves for nearly an year. They were given green signal 2 days before the series kicked off, but proved significant in Australia's 5-0 demolition of England.
Lately, Sky sports has been showing their hotspot figures as well, & I'm sure other cricket broadcasters will take up this brilliant idea in coming days.. exactly like they did with Hawkeye & Speed Gun.