Could a drone be used to detect landmines?

We put Paul's question to tech investor Peter Cowley

Peter - Yes, that makes lots of sense. I mean, yes it's very topical to talk about drones. First, we got to look at what a landmine is and there's a variety of them from the small anti-personnel ones to the larger anti-tank ones which are very small. Over the years, they've been adapted or developed so that they have very little metal in them because metal is detectable with a metal detector etc. which is the old way of doing it. So, one way would be with a metal detector but these detector had a very big coil antenna so the drone have to be very big. It has to be very close to the ground, about 10 centimetres. Now, there's no way a drone.

Kat - That would be a giveaway.

Peter - .can fly 10 centimetres. They could run into a daisy or something or run into a rock. So, there are other ways of doing it. Dogs are used but you can't have a god in the drone, honeybees, rats, there's a Gambian rat and none of these work at all. We mentioned gamma rays earlier on. There's a gamma ray detector but that's quite large. Micropower impulse radars, etc. and there's acoustic ways of doing it. So in principle, there will be something somewhere but the bigger question is, once you've detected it, what are you going to do with it?

Kat - You still got to go and dig it out.

Peter - You've got to pinpoint it exactly and mark it or you've got to set it off.

Kat - We know it's in that field.

Peter - Exactly.

Chris - There's a company who we interviewed. It was about 10 years ago here on the Naked Scientists in Denmark and they have invented genetically modified landmine detecting cress. When these plants grow on an area of land which is contaminated with trinitrotoluene otherwise known as TNT, or other nitro group derivatives that it gives off, they've programmed into the plants. They have a genetic switch which it causes them to make anthocyanin which is the same stuff that makes beetroot go deep red. So the leaves pick up a lot of this stuff and turn to deep red colour. Apparently, it was pretty good but I haven't seen any more reports since so I don't know if it's one of those amazing stories that kind of got started and then they perhaps run out of funding or something.

Peter - The question was on drones actually.

Chris - Well, I was just looking for or thinking outside of the box.

Kat - But if you had a colour change cress, it's a long game. You plant the cress and then you can fly the drone.

Peter - With a simple camera system.

Chris - You land your drone on the red spot and off it goes, and bang with the landmine demined.