New Delhi, Nov. 20 -- Why would a general user care about thermal cameras? That's how it used to be for a long time. Thermal cameras were the domain of building professionals, car mechanics, and the odd wildlife spotter, but the hardware's shrunk and prices have dropped. Today, a decent phone-based thermal camera can slip into your pocket and turn your smartphone into a serious troubleshooting device and a tool for creative exploration. If you're weighing up whether this is just another accessory fad, here's why a thermal camera deserves a spot in your kit.

At its simplest, a thermal camera reveals how hot or cold things are, instantly, at a glance. Simply plug it into your phone's USB-C port, open the app, and you're greeted with a colo...