Accelerometers measure the rate of change in an object’s velocity. When traveling at a constant speed, (in theory, any constant speed) an accelerometer will show a zero reading. But when speeding up or slowing down, the accelerometer will reflect that change in velocity.
Accelerometers can give readings based on the change in velocity in various directions, called axes. A single axis might be in the vertical or horizontal plane, measuring changes in velocity only in that direction. Another perpendicular axis would allow for x-y coordinates, and a third axis allows for three-dimensional tracking. Such a device is known as a triaxial accelerometer, such as our ProAccel 3 Axis Accelerometer.
Although there are a number of ways to construct an accelerometer, the most easily understood concept is to picture a small weight connected to a spring in line with one of the axes. If the accelerometer is moved in that direction, the mass tends to resist motion, and the spring will deform, contracting or extending. Accelerometers measure and report that deformation.
Uses in Navigation
For navigational purposes, an accelerometer gives supplemental information rather than a full picture. It doesn’t provide enough information on its own to chart a course, but accelerometers do play a key role in inertial navigation systems (INS). An INS is a computer-aided navigation system that uses accelerometers and gyroscopes to determine the orientation, location and velocity of the vehicle in relation to a known starting point. Because all sensors and computers are on-board, an INS equipped vehicle does not depend on outside references, making it a powerful tool for planes, ships, and other vehicles that may loose track of conventional navigation aides. This independence from external references also means that an INS is not prone to jamming, an attribute that makes its use popular among military craft.
In recent years, lighter and less costly INS installations are made possible by advances in microelectromechanical systems (MEMS). As the cost to implement an INS has gone down, there has been an uptick in their use in both military and commercial applications. As this demand has increased, the push to develop better and more affordable accelerometers has led to technology that has found its way into non-traditional uses in daily life.
Uses in Wider Culture
Accelerometers have seen recent implementation in consumer electronics for entertainment (movement in game controllers), data protection (locking hard drive heads if a drop is sensed), and orientation adjustment (flipping screen display upon rotation). This technology, that was once too expensive and complicated to ever become associated with home devices, has now become commonplace. The increased demand for accelerometers will certainly continue to push the envelope on what is possible with technology, whether at home, in our pockets, or in our vehicles.
