Motivated by the success of linking a BlueSmirf Bluetooth module directly to the Parallax RFID reader I began to think about how to package the reader in a way that allows you to use it close to or even in the water. A visit to the local DIY store brought up a cable junction box by Ensto, a Finnish company. Intended to shield high voltage electric installations from dust and humidity, the practically water-tight box comes in clean Scandinavian design. It includes an ergonomic front shield with rounded edges and rubber “buttons” on the side and costs no more than $3.
Unfortunately, the Parallax reader does not fit into this little box. Convinced that it is pretty ideal to embody the first Rfish reader, I thought about cutting the Parallax shield between the antenna and the reader logic to squeeze it in. Meanwhile the ID-12, a small RFID reader module with built in antenna for only $29.95, arrived from SparkFun. With the previously gained knowledge, the hint from a squid and a soldering iron (d0 to rx-i, /rst to 5v to vcc and fs to gnd to gnd) it was possible to coax the ID-12 into sending the first ID to my laptop via Bluetooth in half a day. And even better: It’s a perfect fit.
A first test in the kitchen sink seems to prove that both RFID and Bluetooth perfectly work when the box is floating in the water and even when it is submerged a few centimeters. What’s still missing is a sort of feedback in the form of a buzzer or a vibrator, a power switch and maybe a stronger battery (though it has been on for hours now and keeps working flawlessly). Still, I guess we can call this a major milestone without exaggeration.
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