Abstract: A seismic circuit controller includes a ring-shaped first conductor; a second conductor defining a concave conductive surface; a base for supporting the first conductor horizontally oriented above the second conductor, the second conductor being concave upwardly, the conductors being connected in a circuit having first and second circuit nodes. A conductive ball that rollably contacts the second conductor makes electrical contact between the first and second conductors in response to lateral movement of the conductors, an SCR latch circuit of the controller maintaining a low-impedance current flow between the first and second circuit nodes in response to the electrical contact between the first and second conductors when the controller is connected in series with a battery and a load. A control switch that is also connected in series with the load arms the controller when ON and resets the latch circuit when OFF.