Your old iPhone just got more useful.
A free app called Manything can turn your old smartphone into a motion-sensing security camera.
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And unlike other smart home security systems like Dropcam, which costs about $200, this system is currently completely free.
Just install the app on both your old and new iOS device, place the old iPhone in the area you want to monitor and the app will stream the video via the app to the iPhone you currently use.
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Manything will automatically begin recording when it senses motion and can even be set to notify you when it starts filming.
The app also works with old iPads and iPods to be used as security cameras.
For more on Manything, go to BGR.
—By CNBC's Cadie Thompson. Follow her on Twitter @CadieThompson.