- Fri Dec 07, 2007 10:20 am
#39203
I may be biased... I usually want to spend my time on the application objective. It is possible with the Xbee/XBeePro, to add code to their microprocessor. I don't recommend it unless you are doing a very, very cost-sensitive product. There's a long learning curve and the cooperative OS must keep up with the timing demands of the MAC. So a separate microprocessor for the non-trivial application is what I'd recommend. I just did a project like this, where the XBeePro's were plugged into a $40 baseboard from Coridium on which there is an ARM7. (For many needs, a much cheaper/simpler processor would suffice). My rapid-application was a 1,000 lines of code running on the ARM, and the XBee was just a transparent modem, however, the ARM changed the PAN network node destination MAC address to send messages to either the coordinator (addr 0) or a specific node, or a do a broadcast - I had 12 such devices running, battery powered, for a complicated proof of concept test, using 250Kbps (or net 80-120Kbps after overhead).
I've done this same kind of thing, to a lesser extent, with Xbee-equivalents from SiLabs, ZMD, Jennic and plan to try Meshnetics (Atmel chips). The nice thing about 802.15.4 with or without the ZigBee stack, is the IEEE standard MAC/PHY, unlike all proprietary prior low power bi-directional chips. (I leave Bluetooth out, due to cost and PC/PDA-centric protocol stacks on one side of the link).
Other people may want to rediscover how certain MAC and PHY layer communications work. For this, I think you are better off buying a development kit from TI, Ember, or FreeScale (XBee series 1 are based on FreeScale). As a practitioner in wireless for years, it's best to hit the books on MAC and PHY rather than tinker and code.
I've done this same kind of thing, to a lesser extent, with Xbee-equivalents from SiLabs, ZMD, Jennic and plan to try Meshnetics (Atmel chips). The nice thing about 802.15.4 with or without the ZigBee stack, is the IEEE standard MAC/PHY, unlike all proprietary prior low power bi-directional chips. (I leave Bluetooth out, due to cost and PC/PDA-centric protocol stacks on one side of the link).
Other people may want to rediscover how certain MAC and PHY layer communications work. For this, I think you are better off buying a development kit from TI, Ember, or FreeScale (XBee series 1 are based on FreeScale). As a practitioner in wireless for years, it's best to hit the books on MAC and PHY rather than tinker and code.