Hi, I am making a seismograph for a school project and ran into a problem while doing so. I am using a moveable magnet inside a coil that will produce a voltage proportional to the speed of a tremor when the magnet moves. To translate this analog data to digital data i am using an arduino uno. I am using a simple dc voltage meter as seen in the picture below. The problem is that the coil produces a voltage where the positive and negative terminal varies. This means half of the time i get negative voltage readings which the arduino cant read. I was told i coud use the 5v the arduino can give as my 0, so that when i get a -3 voltage read the arduino sees 2v. But how would i wire this? When i just plug in the 5v the arduino reads it but the coil doesnt give any voltage reading anymore when being exposed to a varying magnetic field. I have seen solutions with zenerdiodes but i have no access to these. Is there any way to do this without any more electronic components than the ones given in a standard arduino kit?