Xbee question: Can I read multiple inputs at once?

Wireless & IoT
1

Hello,

I don’t have any xbees yet but would like to know if it is possible to read a complete byte of data at once. Say if you had 8 pins set to DI.

I would like to try something like this for interfacing to an 8 bit counter.

If not, how long would it take to read the status of 8 pins one at a time if the network wasn’t very busy?

Regards,

Robin S.

2

Depends on the mode of the XBee on the processor. In API command mode all the pins on a remote XBee are read and sent. The API command frame needs to be built with the proper format and then the returned frame needs to be parsed to extract the data payload.

Check the documents for the 1S or IS AT command and the API command frame formats.

Another way is setting up the remote XBee to periodically send the pin levels.

Before you buy any XBee modules determine what you really need them to do. There are two hardware versions, Series 1 & 2, and each have a couple of different firmware protocols available.

I started a thread in this forum titled “Better XBee documents”. In there are links to simplified documents about the various XBees. These should be more helpful than the standard Digi Int docs.

3

No, I don’t think the XBee has 8 input bits.

Of course, you can mate the XBee to a $1 microprocessor that would do I/O and send that via serial data to the XBee for retranmission wirelessly as a packet. Or a packet of 100 datums.

4

Thanks for the replies. I had stumbled upon the “Better XBee documents” yesterday so I have an idea of what I’m getting into.

Unfortunately, I believe that I will need the series 2. Eventually I would like to relay an xbee signal over the crest of a hill or along a curved right-of-way through the forest. Is this a true assumption? Which is easier, ZigBee Mesh or DigiMesh?

I was also planning to start with the Funnel (http://funnel.cc/Hardware/FIO). It seems to be geared towards a field install. Might need a slight mod to hook up to a solar panel.

Just a matter of getting some hardware and tyring it out!

Thanks

Robin S.

5

robins:
Thanks for the replies. I had stumbled upon the “Better XBee documents” yesterday so I have an idea of what I’m getting into.

Unfortunately, I believe that I will need the series 2. Eventually I would like to relay an xbee signal over the crest of a hill or along a curved right-of-way through the forest. Is this a true assumption? Which is easier, ZigBee Mesh or DigiMesh?

I was also planning to start with the Funnel (http://funnel.cc/Hardware/FIO). It seems to be geared towards a field install. Might need a slight mod to hook up to a solar panel.

Just a matter of getting some hardware and tyring it out!

Thanks

Robin S.

If you have just one “repeater” to cope with, I’d not use a mesh. I either put in a microprocessor you program to do store and forward, or I’d hook two XBees back to back in serial port extension mode.

A mesh is quite complicated.

If you need a mesh, and don’t care about the quasi-standard ZigBee, I’d use DigiMesh and battery powered router mode.

Or use 900MHz though more costly, and with the right antennas, might get over a not too severe hilltop.

6

Due to my planed layout, I probably would only need one “repeater”. Is there any preference for Series 1 or 2 if using a micro to store and forward data or for two Xbees back to back in serial port extension mode?

Could you also comment on RPSMA vs U.FL Connection? I did notice that series 1 don’t come with the RPSMA connection. Is the U.FL Connection easier to seal up on an outdoor enclosure? How about a vertical PVC pipe with a drilled hole in the cap for the RPSMA to stick out. Then attach an antenna on top. For the U.FL it might be best to mount on the side of the pipe.

Thanks

Robin S.

7

I’m a Series 1 fan because Series 2 is tied to Ember and must use ZigBee.

Ant. connectors: I use chip antennas or U.FL and a pigtail to adapt from that to Type N or whatever. But SMA is fine. Lots of RP-SMA antennas for 2.4GHz. Just a convenience factor.