XBee Pro messaging system using DigiMesh

XBee & XBee Gateway XBee - DigiMesh
1

Hi there,

I’ve been building a system which requires a wireless network for messaging. Basically, there are four main components: a base station (laptop), a gps fix station, relay stations and, multiple robots. I am wondering what sort of networking protocol to set up so I can broadcast a signal from the gps fix station to all robots (amongst other messages flying around the place). All of the messages follow a similar structure which is basically a header (type of message, who sent it, who is meant to receive it and, a message counter), a payload (structure varies based on the type of message being sent but basically comma-separated numbers) and, a checksum value (which is obviously redundant if i end up using API frames).

I’ve written the messaging system based on transparent mode (XBee Pro 802.15.4) and each node has its own micro so I keep track of forwarded and received messages. I’m just wondering if transparent mode is the right way to go as I’ve heard about upgrading the XBee Pro’s to use DigiMesh.

Any pointers would be a great help

Cheers

Ian

2

Digimesh should be able to handle the broadcasts as long as you only send them once a second or less (whereas ZigBee can’t really).

The difference between 802.15.4 and DM is that 802.15.4 Xbee do NOT repeat broadcasts since they all assume line-of-sight. So DM does need to repeat broadcasts just in case other Xbee are out of range. So you might want to play with the Dm settings to reduce broadcast propagation delay to a minimum.