802.15.4 has always been the "if you can't be with the one you love, love the one you're with" kind of solution. So it makes sense to look at the alternatives from time to time, to see if anything has changed in the field.
Ron sent me a few pointers to Bluegiga BT modules, triggering one of these scans. First, let's look at the Bluegiga products: - Bluegiga are kinda cute and sourceable, but they also rely on Windows-based development tools for putting applications into their modules. The price tag is also significant, with 1000 units starting at USD 13.65 (BLE113). For comparison, all the major components of Anelok (excluding the PCB itself, case, etc., but including 802.15.4 transceiver, balun, and PCB antenna), together cost around USD 15 at 1000 units. Of course, having BT would make the RF (802.15.4) dongle optional, so even such an expensive module would be about neutral if we look at the cost of the entire system. Still, the closed development tools aren't nice. There are also some discouraging things on their forum, like "problems loading the licensing key into the module" that suggest that more trouble awaits the ones taking that road. - Ron also found out that Bluegiga use CSR and more recently TI CC254x chips. Now CSR does not sound too good, but the TI CC2xxx are fairly popular. The problem with most of the available BT solutions, especially if they're modules (and not chips) is that they tend to have some proprietary firmware that is either completely closed or at least not easily modified (even if there's an SDK, there may be restrictions on redistribution, the SDK will be closed-source, and so on.) To avoid this, one would have to go one level below: just get a chip that takes care of the physical layer (aether to bits) and maybe also the link layer (bits to packets) but then do the rest in the firmware. Among other things, that also has the potential benefit of moving the local end of the protection of any encryption that happens on the radio link into the MCU. So any snooping on that interface would be defeated. This may not be the most likely place where an attack may occur, but today's far-fetched hypothetical weakness may very well become the exploit in tomorrow's headline news. Next: why we don't need to use the machete just yet. - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
