Spooked by spirits? There's an app for that.

If there’s something strange in your neighborhood, you don’t need to call Ghostbusters. Just launch a ghost-hunting app on your smartphone. They’re designed to use sensors built into your phone -- such as the gyroscope, magnetometer and accelerometer -- to mimic the function of equipment used by professional and hobbyist paranormal investigators. Whether or not a mobile app is capable of measuring paranormal phenomena is debatable, but you want to check out your surroundings, download and install some ghost-hunting gear.

Ghost Radar: Legacy (iOS, BlackBerry, Windows Phone, Android; $0.99)

• Ghost Radar: Legacy uses the sensors on your phone to measure electromagnetic fields, vibrations and sounds around you, then employs a proprietary algorithm that takes that data and uses it to measure quantum fluctuations – temporary changes in the amount of energy around you. Readings are displayed numerically on the Vox tab of the app and as colored dots and words on the Radar screen. According to the developer, “intelligent energy” can influence the sensors on your phone and communicate with you through the readouts displayed onscreen.