These little devices are made by Square Inc and designed to allow you to use your smart cell phone as a credit card reader. Being given away free, we asked for one last year, but having since found no legitimate use for it, we decided to tear it apart and see how it works. Here it is:

A simple magnetic head reader, VERY similar to the old ill-fated cassette players that used these to read the song on a magnetic tape. The construction is so simply I couldn’t believe it! a magnetic reader, and a single set of wires to send a signal. Note the brown black brown 0.125watt resistor in line with one of the wires.

I hope this helps someone or you! Lets see someone copy their credit card info, and then relay it onto a cassette, or something silly!