So my guess is, it's a bluetooth radio and a XBee. Nice? I think? What surprises me is the size of it; I've deployed exactly this (minus the spiffy packaging, a

So my guess is, it's a bluetooth radio and a XBee. Nice? I think? What surprises me is the size of it; I've deployed exactly this (minus the spiffy packaging, admittedly) for barge tracking applications since 2008, and the whole thing ended up being roughly the size of an early 2000s palmtop computer, so good job on that! The schematic is trivial: a xbee XSC (we used XStreams at the time) with a decent antenna coupled with any serial bluetooth module. The whole thing runs on 3.3V with high tolerances, so a single lithium cell is enough to power it without regulation. If you can't do meshing for legal reasions, do a transparent blind forward -- for short messages that you don't mind a delay for, it works out well, and the FCC (and the coast guard) have been OK with it. If you want my design contact me at www.f3.to