A spring-mass system is able to detect acceleration due to the restorative force the spring puts on the mass. The simplest of spring-mass systems consist of a spring attached to a wall perpendicular to the base along which the mass can move as a result of acceleration; the mass is attached to the other end of the spring. At the spring’s relaxed state, acceleration equals zero.
Calibrating the device requires a fairly accurate protractor and calculator or a spring scale in order to determine the accelerations which are occurring at different distances from the relaxed state.
In the production of a spring-mass accelerometer, friction is important to keep the mass from oscillating at the spring’s natural frequency. In the absence of any frictional force, a spring-mass system pulled back to a distance –x will oscillate back and forth between –x and x.
The natural frequency is the cycles per second of this oscillation. In order to make an effective spring-mass accelerometer, a frictional force or damping force is required to keep the mass from oscillate and go to the intended position during acceleration. The trick is not having too much or too little friction in the system.
A limitation of the spring-mass accelerometer is that it is impractical (though possible) to measure acceleration in more than two directions. As well, the ability to change the spring(s) being used and mass being used are important if not a limitation on the range of acceleration possible to record. Size is another limitation because a spring-mass accelerometer needs to be large enough to accurately read the values off of the scale being used.