Our eyes cant see it, but digital cameras surely can. A smartphones camera is indeed sensitive to IR radiation, and if you want to try it for yourself, just use a common IR remote control. The infrared beam emitted when a button is pressed will show as white or purple light in the viewfinder of your camera app. You can use this trick to check if a remote controls batteries are dead when it stops working.

Many countries now issue passports with embedded RFID chips. These store data about the documents owner, including their photo and a scan of their fingerprint. And apparently, some of the owners information can be pulled using a smartphones NFC radio and an app made for the purpose. This, however, isnt going to work with all passports. Take a look at this thread over at XDA-Developers to learn which countries passports can be scanned with a smartphone.

As you can see in the video, Bluetooth headsets can be used as remote shutters for a smartphones camera. This would let you take photos from a distance – perfect for spies at heart! Theres a catch, however. You shouldnt be expecting this hack to work with just about any headset. Whats more, youre on your own in figuring out which button or button combination makes the camera go off.

Yup, your smartphone can mine Bitcoin and other cryptocurrencies. Youre not going to become a billionaire overnight, however. In fact, youll probably be making a few cents per day even on a high-end phone. Thats why using a smartphone for the purpose is anything by practical, not to mention that the burdening task would quickly make its internals heat up. Still, it cool knowing that a smartphone can be a Bitcoin miner, albeit a humble one.

Believe it or not, a smartphone can be used in the fight against cancer and other hard-to-cure diseases. Using a free app called Samsung Power Sleep, one can donate the computational power of their mobile device for the cause. The software analyzes data at night, while connected to a charger, and then uploads the results to help researchers in their anti-cancer studies. HTCs Power To Give app works in a similar fashion, and processing power can be donated to various medical, environmental, and scientific projects.

Amazingly, it just takes a drop of clean water on the camera lens to turn a smartphone into a DIY amateur microscope.  The drop of water, which naturally adopts a round shape, acts as a lens, allowing the camera to focus from a distance of under half an inch. The steadier your hands are, the clearer the image is going to be. Needless to say, be careful when you try this as you dont want to get any water inside your handset. The picture you see here has been taken with an LG G2 using manual focus and a flashlight illuminating the subject.

An OBD (short for on-board diagnostics) is a device that plugs into a cars computer unit. It is used to monitor the status of the vehicles systems and to diagnose problems that might have occurred, as indicated by that cryptic yellow light on your dashboard. And with the help of a dongle that you can buy online, your smartphone can serve as an OBD that reports car data in real time. Youll need an app as well, of course, and we have just the thing. These are some of the best OBD car apps available on Android.

Thanks to Androids USB on-the-go functionality, we can connect most common USB devices to newer Android-based smartphones and tablets. USB sticks can be hooked up for file transfers, and a connected USB mouse can be used for navigating the UI. Youll most likely need a USB on-the-go cable to pull this trick off, however, although some cool new USB drives come with both a micro- and a full-sized connector.

You might be surprised to know that this actually works. Well, kind of. Distance measuring apps cant match the precision of an instrument made for the purpose, but they should prove good enough when a rough measurement is sufficient. They use trigonometry to calculate the approximate distance between the user and a visible object. To get the distance, you just have to input the height, at which youre holding the smartphone, and to aim the crosshair at the base of the object.

And speaking of measurements, a smartphone can provide (somewhat reliable) altitude data using its GPS radio. Newer models can also detect their position above sea level and atmospheric pressure using a built-in barometer.