Near Field Communication This tutorial will have you make a coil
for NFC and connect it up to your Pi. It will then teach you how
to send and receive messages through your coil to give your
Pis/robots a new way to communicate. You will probably also want
to find another person doing this tutorial or a spare robot so
you can test both sending and receiving messages. NFC is a
simple form of wireless communication. On the sending side we
have a coil of wire connected through a transistor/OP-AMP so
that we can push large amounts of current through it. Using the
general purpose clock we can drive this at 64 KHz (a frequency
that our circuits are tuned for). This means that we are very
rapidly (64000 times a second) turning the coil on and off. This
means there is an alternating current going through our coil of
wire which in turn creates a rapidly changing magnetic field.
When a second coil (the receiving side) is brought close, its
wire is being “cut” by this magnetic field as it changes and so
a current is induc