You’re likely already acquainted with RFID (radio-frequency identification) and its cousin NFC (near-field communication). Both are battery-free communication methods that receive power remotely through an antenna, and then respond with data. They’re handy for simple one-way communications, like for unlocking a door or paying for purchases. But, they lack the hardware needed for interactions between tags. RFIMatch is designed to change that by allowing two tags to simultaneously register so they can be paired.
A conventional RFID setup has a powered reader that energizes the antennas of one or more nearby tags. Once the chips in those tags have power, they transmit their data back to the reader. RFIMatch works by putting a reed switch between the tag’s chip and antenna. The reed switch has a small magnet on one of its terminals, which keeps it normally closed so the RFID tag can work as usual. But, when two RFIMatch tags are placed near each other, the opposing forces from the magnets open the reed switches simultaneously and disconnect the antenna.
When the two antennas are disconnected at the same time, the RFID chips stop transmitting data. And, because the two tags were deactivated simultaneously, the reader can determine that they have been “paired.” You could, for example, have three completely battery-free tags: an “activator” tag, a “lights” tag, and a “stereo” tag. When you touch the activator tag to the lights tag, it could turn on your lights. Touch the same activator tag to your stereo tag, and it turns on your stereo. While that’s a simple example, RFIMatch enables more sophisticated interactions than traditional RFID tags.