Don't be left in the dark when the ground starts shaking.  Here are the three best earthquake detectors you can own.

First up is the Earthquake Alarm.  This pocket-sized unit emits a loud alarm before the ground starts to shake.  It anticipates earthquakes the same way dogs do.  An internal, reverse pendulum detects slight vibrations in the air, which travel faster than waves in the earth do. This earthquake detector will give you a few valuable seconds to secure loved-ones and find a safe location to brace against the immanent quake.

Next is the AMERICAN RED CROSS Earthquake App.  This one is available both the iPhone and Andoid.  This doesn't just tell you when and where earthquakes are occurring.  It has a step-by-step guide to follow after the earthquake hits.  Now you can have official Red Cross guidance for preparing for and recovering from an earthquake.  And it works without a data connection.

Finally, we have a good ol' fashioned seismograph.  This classic meter measures seismic activity that would otherwise go undetected.  The seismograph gives a clear and simple visualization of the rhythm and strength of an earthquake.  It can also be used to anticipate large quakes by graphing the smaller foreshocks.

Or, you can just make your own earthquake detector in the style of Ancient Chinese astronomer Chang Heng.