Various embodiments of sensors and related methods for measuring force and/or detecting acceleration or vibration are disclosed. A system may include a hollow enclosure and a rigid base attached to a lower end of the hollow enclosure. The rigid base may allow for the passage of light therethrough. A piston may be disposed within an interior space defined by the hollow enclosure and rigid base. The piston may be moveably secured to the hollow enclosure, such as by a plurality of springs. A flexible bladder may be disposed between a lower surface of the piston and an upper surface of the rigid base. A camera may be disposed beneath the rigid base and aimed upwardly toward the rigid base. A computer may be connected to the camera. Various other details are provided.

A weighing device includes: a support having a placement surface on which an object to be measured is to be placed, the placement surface being displaced according to a mass of the object to be measured; a mirror disposed on the support; a laser interferometer configured to detect, using a laser beam, a change in optical path length to the mirror due to the displacement of the placement surface; and a controller configured to calculate a weight or a mass of the object to be measured based on the detected change in optical path length, in which the laser interferometer includes a laser light source configured to emit the laser beam, and a optical modulator including a vibrator and configured to modulate a frequency of the laser beam using a vibration of the vibrator.