(NYSE: INVN)

The exploding number of Google Android devices has become a cash machine for microchip maker InvenSense Inc. (NYSE: INVN).

InvenSense makes the tiny motion sensors used in 70% of Android phones and 90% of motion-sensing Android tablets.

Mobile device makers have enthusiastically adopted Android, an operating system developed by Google Inc. (Nasdaq: GOOG), because Google licenses it for free.

Growth in Android devices is exploding.

At the Mobile World Congress in Barcelona last month, Google Senior Vice President for Mobile Andy Rubin announced that 850,000 Android devices are activated every single day, for year-over-year growth of 250%.

That kind of growth offers tremendous potential for a company like InvenSense, which only went public last November.

With 512 million mobile devices expected to be sold by 2014, the market for InvenSense promises to be huge.

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These motion-sensor chips, called Micro Electro Mechanical Systems (MEMS), are what enable mobile devices to react to tilting or shaking.

Although MEMS technology has existed for decades, it was when InvenSense's motion sensing chips were used in the Nintendo Co. Ltd. (PINK ADR: NTDOY) Wii controller in 2006 that the technology started to go mainstream.