I bought a geophone on internet: SM-24 produced by Sensor Nederland b.v., it's a 2-ms sampling 10Hz-240Hz.
I would like to interface it with Arduino and acquire data.
As SM-24 give an oscillation signal around 0V, for first I wanted to try to use +3.3V of Arduino as reference (0V) and amplify the signal (about +/-0.1mV) from 3.3 +/-1V: about 10 times.
I tried it with LM324... but I am a noobie and doesn't work:
actually I don't know:
how to connect geophone (with resistence or not? or what else?) to circuit
how to make LM324 works and which resistances to use
...
finally:
can anybody suggest me a schematic to test?
Don't have my Uno yet bet do know geophones quite well. Output voltage and the geophones terminals will go positive and negative as it is vibrated. The Uno only accepts voltages 0 to +5V so that's a problem. You will need an instrumentation amplifier such as AD620 powered by + and - DC supply such as two 9V batteries. Then connect a 2.5V reference chip to the Ref pin . This will offset output of the AD620 +2.5V so that while the geophone outputs + and - voltage, the output of the AD620 will be 0 to +5 to make the Uno happy. Geophones can output high voltage when hit hard or dropped so you may need a voltage divider or attenuating opamp circuit on output of the AD620 depending on how hard the geophone will be vibrated. This will be one of my projects so can't promise good results. Maybe try connecting the geophone through an A/D converter into the Uno. Thinking about MCP3002 A/D from sparkfun.com.