Schweydar mechanical detector

Schweydar mechanical detector

[′shwād·ər mi¦kan·i·kəl di′tek·tər]
(engineering)
A seismic detector that senses and records refracted waves; a lead sphere is suspended by a flat spring, the sphere's motion is magnified by an aluminum cone that moves a bow around a spindle carrying a mirror, and this motion is then photographically recorded.