That dusty iPhone 5 in your bottom drawer could stop your house burning down.

You’ve probably got a banged up old mobile phone knocking about in a drawer somewhere, but you’re only hanging onto it in case you drop your current one down the toilet, or just so you can one day amuse your half-robot great grandchildren by showing them how us luddites used to communicate.

Actually, it’s far more useful than you might think. Download this Smokey app to that disused old talker, and you’ve got an incredibly smart little life-saving device on your hands. Who’s laughing now?

Smokey works simply by listening out for your smoke alarm when you’re not home to hear it yourself. Simply download the app, connect your old phone to the power, and leave it to handle the rest.

If your smoke alert sounds, Smokey will pick it up using its clever sound analysing tech and instantly send an alert to the app on your shiny current phone to let you know there’s trouble afoot.

And that’s pretty much it. No expensive gadgets, no fiddly set up – just a shiny free app for your poor neglected old phone that might just save your skin.

You can download it now for both Android and iOS phones.

Love this? You might want to check out some of these awesome apps that turn your old phone into a security camera.