The project on Seismic sensor circuit described here senses pressure variation or mechanical strain and responds by sounding a speaker. It can be used at [[wysiwyg_imageupload::]]prohibited places to alert any unwanted entry. Such sensors can be placed on the floors of these places and whenever an intrusion would occur, the speaker would go off. The term “Seismic” is used majorly for all the operations and processes related to the earth, its crust and lower layers. The similar areas are there where this sensor finds its applications:   1. Decoding natural vibrations under the earth’s crust through seismograph   2. Aid in large industrial processes of oil extraction drilling process, mining, tunnel construction etc.