Optical Transducers

Each transducer is a LED/phototransistor pair that are mounted facing each other, in what is henceforth called a "fork." The fork must be carefully positioned such that the string at rest partially obstructs the light passing from LED to the phototransistor. The string does not need to be an electrical conductor. Optical transducers measure the string's displacement. With two of them mounted at right angles, both horizontal and vertical deflection can be measured. Optical transducers are best mounted near one end of the string.