The buffer, also known as a unity gain amplifier, is an op amp with a gain of one. Its purpose is to prevent backwards loading from the rectifier to the reader.

A full wave rectifier essentially flips the bottom half of the waveform to make it entirely positive.

I am using a rectifier to support the comparator, which cannot take negative signals.

The newest addition to our family of components, the comparator uses the voltage divider on the left to compare the incoming signal. If the signal is lower than the decided voltage, it outputs a zero. Otherwise, it outputs 5V.

The Pi will take the input from the comparator and turn it into binary data. Then, using Bluetooth, it will send the data to ion via a local program.