Wall Routers and Gateways


First off, I apologize if I say anything naive. I have this project I’m being thrust into and I don’t have a great background in wireless embedded devices, and so far have focused mainly on what’s possible with TI’s chips. I’ve come across these drop-in solutions and am trying to figure out if they’re a better fit for what I’m trying to accomplish.

I’m looking at building a simple network that has routers scattered sparsely along a long building. End-devices (such as a Xbee Pro) sleep, wake up and join the ideally (according to Zigbee’s spec, but understand lots of variables can throw this off) strongest RSSI router it can see, upon joining the network it sends an empty message to the router some number of times while the router keeps a running average of the RSSI. Once the end-device is done chirping it leaves the network and goes back to sleep. Upon it leaving, the router it was connect to should recognize this and send the RSSI back to the coordinator so that it can be gathered by a PC for processing.

My questions are: Are the wall routers able to be programmed in this way? If so, what’s the means for doing this (firmware?). Also, would anyone recommend using the gateways Digi sells for the job of the coordinator rather than having a PC for each one (I’m likely going to have to have multiple of these networks due to hop limitations).

Also, a more general question, how does one determine when a mesh network is exceeding the hops limit of the Zigbee specification? It’s quite obvious in a tree configuration, but in a mesh I’m concerned with how many networks I may need to setup to cover a certain distance. I think the Zigbee specification says there’s a 6 hop limit, but I’ve seen conflicting information on this forum so I would appreciate this being cleared up if anyone has the time.