LED Activated Relay Board for a motor.

[benj.1]

I am an architect student and currently looking into ground vibrations.
I am using a device called a geophone which picks up ground vibrations i the ground and turns into a voltage. I want that voltage to trigger a motor when ever there are vibrations in the ground. I have tried connecting the geophone to the 12v motor via a LED Activated Relay Board. (and a 9v battery)
The relay is triggered when a signal of over +1.4Vdc is applied to the input and turns off when the voltage falls to zero. It has a relay output capable of handling 250Vac/1A.

Aut the the voltage produced is too small, roughly 0.8v. How can i get this to work!


Any help, comment would very much appreciated.

 

[Diver300]

0.8 V will turn on a transistor. The transistor can turn on a relay. You will need a freewheel diode in parallel with the relay.

 

[benj.1]

thankyou, but what is a freewheel diode?

 

[Diver300]

A freewheel diode is also known as a flyback diode.

The current in a coil, such as a relay coil, can't stop instantly. If you try, you get big voltages which damage things. So you add a freewheel diode in parallel with the coil. This does nothing until the switch or transistor turns off. It then provides a current path and the coil current slows down over usually 0.1 - 1 second without any big voltages.