USING A GEOPHONE WITH OUR ARDUINO SEISMOGRAPH

摘要

Reader Michael,from western NSW,kindly sent us a model 20DX geophone sensor,suggesting that this would be a great add-on to our seismograph project fsiliconchip.com.au/Article/11030l.The geophone sensor is based around a sprung mass(a magnet] moving inside a coil.It generates a voltage proportional to the velocity of the magnet.This is different from the MEMS type sensors,which produce a value proportional to acceleration.While larger and heavier,the simple mechanical geophones are also much more sensitive than their MEMS counterparts.The geophone sensor is marked with the code “10 395”,meaningithas anominal minimum frequency of 10Hz,and a coil resistance of 395Q.Similar units are available from many online sellers.The unit we are using is designed for use in a vertical orientation,although units designed for horizontal use are also available.Rather than building another seismograph from scratch,we decided to add the geophone sensor to our seismograph project.It records seismographic data as WAV files,which can be either manipulated and viewed with programs such as Audacity,or simply played back as audio.The data from the geophone sensor is added as a fifth channel to the WAV data,complementing the existing Z-axis(vertical)channel,so all the data can be viewed together and compared.