kerpow

Member Since: January 27, 2010

Country: United States

  • I like series 1 radios better than Series 2 for mesh networks. You do however need to flash the radios to the XB24-DM firmware to use these in a mesh network. (Though if you are reading any zigbee only device or need ultra low power end nodes zigbee is the way to go.)

  • An Xbee in transparent mode (default) will pass anything except "(pause) +++ (pause)" so I would check what TeraTerm is sending.

  • I bet you are broadcasting all the data to all recipients. If you don't set the destination high and low (DH and DL) to the serial high and low (SH and SL) of the destination somehow, then the Zigbee models are slow (about 1 packet a second slow.) use a series 1 in 802.15.4 mode if you want fast broadcasts. (digimesh will do it better than zigbee mesh but any mesh has a little overhead.)

  • A totally closed steel box will block the signal, I recommend putting antennas on the outside of steel boxes with something like the RPSMA version and an external antenna. That said you should be getting way more than 2 feet out in the open.

  • With any good adapter like the xbee explorer (on this site) you can flash the series 1 modules to a mesh mode. you just select the correct DM firmware in X-CTU. I have had a 20 or 30 node series 1 network running great. It is also easier to get working on a series 1 radio. That said, if you want ultra low power on the end nodes and are not afraid of the (painful to learn) sleep settings the zigbee (series 2) stuff can be very nice.

  • 2.4 Ghz has more bandwidth. A bandwidth hungry protocol like Zigbee needs all the space it can get and would hardly work at 900 Mhz. I think that is why you only see digi making 802.15.4 and digimesh stuff in the 900 mhz band; they are both quieter protocols and wouldn't eat the whole available bandwidth.

  • I think the wire version is the best radiation pattern, but this one is a nice form factor and better than the chip version. For truly great range (better radiation pattern that is, they are all the same power level) the full RPSMA antennas are the way to go, but do require an extra purchase.

  • There are two firmware settings you can flash this to an XB24 802.15.4 firmware and a XB24-DM DIGIMESH 2.4 firmware. Digimesh is point to point and better for general hobby use than Zigbee (series 2) in my opinion. Be careful flashing firmware, you should double check that you have an adapter capable of flashing firmware. (it needs all 4 preferably 5 serial lines to flash, not just the TX and RX like most arduino shields have.)

  • If the coordinator is out of range there will be no coordinator, the coordinator is just a router that can start a brand new network without needing to ask an existing router. That said If your network is going to be moving around a lot I prefer flashing some 802.15.4 (series 1) radios to digimesh mode. The digimesh mode lets any node route traffic and helps keep the network happy in weird situations like this.

  • I know it has been a year but I figured I would respond to this. So many people I know buy a Zigbee (series 2) XBee thinking it will be better, but the Zigbee protocol is really designed for a certain special niche where you need low low power end nodes and very few broadcast transmissions. To get a series 2 to talk like you want you would need to change the DL and DH on each radio to match the SL and SH of the radio you want it to send to. (you could also use API mode to send a DL and DH with each packet if your controller has the smarts to do so.). Sending with no destination is a broadcast and every time you try to broadcast the network will wait and wait for any possible responses. If it instead knows the destination it is a nice fast simple send and reply.

    Or you could get a series 1 radio like you mention, they run point to point (802.15.4) or Digimesh either of which would run a ton faster in this situation.