The string potentiometer is composed of a measuring cable, a spring loaded spool and a rotational potentiometer. The stainless steel measuring cable is wound on the precision machined spool that turns as the cable extends or retracts. The device converts the linear movement of the cable into rotation and then into an electrical signal proportional to the movement.
String potentiometers are durable, easy to install, simple to use and inexpensive. They may be used to monitor displacements during pile load tests or to monitor movements across cracks and joints. They may be easily read by most dataloggers.