Here’s how to build a low cost RFID skimmer (it reads the contents of a RFID tag) – wow! “In this study we show that the modeling predictions are quite accurate. We show how to build a portable, extended-range RFID skimmer, using only electronics hobbyist supplies and tools. Our skimmer is able to read ISO-14443 tags from a distance of $ approx$ 25cm, uses a lightweight 40cm-diameter copper-tube antenna, is powered by a 12V battery–and requires a budget of $ approx$ $100. We believe that, with some more effort, we can reach ranges of $ approx$ 35cm, using the same skills, tools, and budget.” [via] – Link.