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Accelerometers can be constructed in various ways, but they all serve the same two primary purposes. A capacitive accelerometer uses a sensing mechanism, known as a capacitive acceleration sensor, to measure both static acceleration and dynamic acceleration forces. With consideration to all accelerometers, there typically is some sort of electrical circuitry wired to the sensing mechanism in order to portray the output, or voltage, of its measurements.
Static acceleration force is generated by a gravitational pull. When measuring static acceleration with a capacitive accelerometer, the measurements would portray the angle of tilt at which the device is being held or suspended in relation to the Earth's gravitational pull. A common capability of many modern cell phones, smart phones and personal digital assistants (PDAs) is that the orientation of the screen changes in relation to the angle at which the device is being held.
Dynamic acceleration force is generated by vibrations from movement. Measuring vibrations allows a capacitive accelerometer to determine in which direction the device is moving and at what speed. Additionally, dynamic acceleration can be measured to track the impact that an object encounters.
Capacitive acceleration sensors contribute to the collection of all static and dynamic acceleration energy. The basic construction of this mechanism is comprised of a movable microstructure or an oscillator paired with one or more microstructures in a solid or stationary state that stores capacitance, providing definition to the name "capacitive accelerometer." The capacitance, or energy generated by these components, charges an electrical circuit upon which the sensor is attached.
The electric circuitry is designed to measure the output or voltage generated by the sensing mechanism. Through a series of detection circuits, which measure the peak voltages, the peak voltages are measured incrementally. The measurements are processed by an amplifier that provides a sum of all given measurements as the final output. The final output would be the reading shown to the user collecting data from the device.
The spectrum of uses for a capacitive accelerometer has quickly grown as the technology of many industries has continued to advance. Capacitive accelerometers can be credited with providing means for many such great strides. Through the use of the capacitive accelerometer, engineers have been able to collect uncharted data and improve their products even further. This has given consumers access to products such as safer automobiles and more entertaining games that require the user to actually interact with the environment.
@KaBoom - You're right, capacitive accelerometers are "yesterdays news" as far as cell phones go. Which is a shame, because, as you said, the concept is pretty neat.
I was unaware that capacitive accelerometers had anything to do with automobile safety though. Just goes to show that many technological advances have other, more practical, applications that just making our cell phones more fun!
Capacitive accelerometers sound pretty amazing. I guess I take it for granted that my cell phone screen will be "right side up" whichever way I hold my phone.
I remember when cell phones screen didn't do the flip though. I also remember that when those kind of screens came out everyone thought it was the most amazing thing! How quickly we forget and look towards the next advancement though.