GEOPHONE: We recommend using a RGI-20DX 4.5 Hz, 395 Ohm, Vertical Racotech Geophysical Instruments geophone. Here are the specs: Geophone Technical Specifications. For the moment, if you are thinking of forwarding your data to the Raspberry Shake Community in real-time, this is the only geophone that will be accepted for use in the automated earthquake detection process. This is because we know the instrument response of the Raspberry Shake board with this geophone. The Raspberry Shake Community server will treat non RGI-20DX geophones as unknowns with unknown instrument responses. (The instrument response is used server-side to determine the magnitude of earthquakes. It allows us to correct the signals to true earth motion and compare seismograms recorded by different makes and models).
Geophone Polarity: If you are using a RACOTECH geophone from OSOP and you connect the grey cable from the “+” on the geophone to the “+” on the Raspberry Shake board, the output signal will have the correct polarity.
If you wish to use a non RGI-20DX geophone, the geophone should be a 4.5 Hz geophone in the range of 380 to 400 Ohms. 1 Hz and non 380-400 Ohm geophones will not work with Raspberry Shake's analog front end.
Caution!: The geophone input is ESD sensitive, and ESD precautions must be taken when hooking up the geophone.
PROGRAMMING: For those of you who are interested in programming your own routines to visualize and process the data, we recommend using the ObSpy Python library. This is a really cool tool for exploring your Shake and doing amazing things with the data.