Low cost PC-based instrument for monitoring long period one-dimensional horizontal ground motion using Lehman seismometer

Abstract

A PC-based instrument was designed and implemented using a Lehman seismometer sensitive to the horizontal direction of long period ground motion. An amplifier circuit was developed to increase the induced voltage generated by the sensor which arises from the relative velocity between the seismometer coil and magnets. The instrument was interfaced to a microcomputer through its parallel printer port using a 12-bit analog-to-digital converter circuit. A software program using Turbo C was written to automate monitoring and continuous recording of data. Collection, recording and analysis of data were done at the Physics Laboratory, IMSP, University of the Philippines Los Baños,