The piezoelectric part of a kitchen gas lighter has used this easy, nonetheless effective seismic detector. The piezo part should be mounted vertically, one finish firmly to the bottom. A weight of 2 ...

My mornings in IIT Kanpur, where I teach, are interspersed with sips of green tea, the longing calls of peacocks and peahens, and the purposeless barking of my neighbour’s dog. Often making things ...