THE threat from fires that come with a tree change calls for some ingenuity, writes CHRIS McLENNAN

A Ballarat radiologist has designed a fire defence system for his hobby farm which has the potential to save lives.

Simply, Alex Pitman can calmly watch a fire rushing out of the nearby forest and turn on his 30 rooftop and other sprinklers to save his home, all by remote control.

He designed it that way because he doesn't plan to be there.

"The safety of my family comes first and last," he said. "Our fire plan is simple if there's a fire close by we leave. We are not going to stay and defend."

The Pitmans have already spent one night in a Ballarat hotel this summer after a scrub fire came dangerously close.

"Fires are the price we paid for our tree change, but that doesn't mean we can't do anything about it," he said.

"Just because we plan to leave doesn't mean we want our house to go up in smoke."

The Pitmans' 7ha block is nestled in creek valley on the edge of the Great Divide, surrounded by state forest.

It was a joyous end to the search for a tree change from Melbourne just three years ago.

But so soon after the horrors of Black Saturday, they recognised their dream home may be a death trap.

Alex, who his wife says is a sucker for an engineering problem, has set about in the past three years to fix it.

He decided on a virtual robot sentry - a system which could save his house using little water and his family.

First, there was the clearing of trees from around the home and the access road.

Then came an upgrade to the four fire prevention sprinklers left by the previous owners.

Now there are 30 most on the roof, some on the gutters.

Only having access to rainwater tanks, a salty bore and a small catchment dam, Alex faced the problem of only having a few hours of water supply.

With the help of local experts they designed a system of recycling so the dam water from many of the sprinklers runs back to the dam to be re-used again.

Valves close access from the gutters to the rainwater tanks so their water supply is not polluted.

The new diesel pump has a modified tank to provide eight hours of run without refuelling.

And it has its own pre-paid mobile phone, with a wi-fi signal, so Alex can turn the pump on and off with his phone, from wherever he happens to be.

So he is not wasting precious water if the fire is not close enough, Alex uses an off-the-shelf surveillance camera system developed by Melbourne company Swann.

Eight cameras point outwards at all points of the compass from under the eaves, with a battery pack in case the electricity is lost during an emergency.

Alex can check on his iPad or iPhone to see in real time just how close the fire is, and decide when to switch on his eight hours worth of water.

There are all sorts of other ingenious add-ons which makes the invention unique, like the night-time infrared capability of the cameras, and Alex admits he is still working out some of the bugs, but the system works.

He can watch the fire, alerted initially to the presence of a fire in the areas through the CFA alerts, and can turn on his sprays, all from his office, or place of refuge.

Total price on tree removal, sprays, pipes, pumps and electronic gizmos is so far about $40,000. When he's finished, Alex reckons he will have outlaid $50,000.

"I have used all sorts of local experts to help me get to this stage, and maybe now it's been proven it can help others."