Xbee cyclic sleep accuracy

XBee & XBee Gateway XBee - 802.15.4
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1

I’m currently teaching myself how to build a meshed sensor network. It will monitor temperature, light and humidity. The furthest node will be out of range of the co-ordinator. Readings will be taken every 10 minutes by all sensors simultaneously and transmitted back to the co-ordinator. All nodes will run on batteries, so I want the wake time to be as short as possible.

The plan is to use Xbees in cyclic sleep mode, but after reading round I’m not sure whether the internal clock is accurate enough to keep all sensors sync’ed with each other i.e. will they all continue to wake at the same time? I’ve googled and googled, but haven’t found a definitive answer, any thoughts much appreciated.

I’m aware that the Digimesh protocol could be a better option than Zigbee for this application, but I already have several series 2 radios and would like to continue using them if possible.

2

A zigbee end point must be in range of a coordinator or router.

Neither can sleep, only an end point.

Your router that doesn’t sleep will be always available to pass the message on to the coordinator.

3

Thanks, I now realise I read some misleading information somewhere that said under some circumstances end points can extend the mesh. This was clearly wrong.

Sounds like Digimesh is my best option, I won’t have enough battery life to power the routers for the length of time required.