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.   

Wastage of water is quite prominent in urban as well as rural areas and overflowing of water tanks is a major reason for that. The circuit described here starts [[wysiwyg_imageupload::]]ringing as soon as the water tank becomes full. Thus, by warning the user, the project avoids the need to check overflow and prevents wastage of water. To detect the overflow, this circuit uses LM324 a 14 pin quad-op amp IC. In this circuit, this IC is configured as a comparator which produces its output on the basis of resistance comparison.Read more to find out how the circuit is designed and how it works.