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Author Topic: Need help in selecting XBEE 868 Mhz part  (Read 1410 times)
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Hi
 I need help in  choosing an XBEE 868 MHZ part so that I can
solve the following problem. I am new to XBEE..

I have a small farming prototype which I am going to choose
the arduino FIO.

I chose 868 mhz for long range and low transmit power.
my data can be as slow as 1200 baud.

1. I would have 20 Arduino fios with some soil and temperature sensors
and light level sensors.


3.0 I would like to try to change batteries every 2 months or longer if possible.

3.1 I would be using alkaline batteries
 (FIO is limited to 3.3 volt but the FTDI cable is actually providing 5 Volts so 3 D sized
alkaline batteries providing 4.5 volts when new should work? or should it be 4 D
sized providing 6 volts when new?)

4. The Ardunino Fios will be in sleep mode and wake up and transmit their data and go into  sleep mode
every 30 minutes.

4.1 transmission would be turned off when no light is detected using a LDR (nighttime)
if growing lights are turned on, the transmission will start again since I am also
measuring light levels.

5. The main receiver would have a very large battery or is AC powered, like
a LAPTOP.

I understand XBEE 868 digimesh is a restricted export controlled product.
so I would like to avoid that as much as possible.

I am counting on the long range of the 868 mhz to avoid having to buy
digimesh based products that can self repeat infomation.

My terrian would have some small undulations on it as it is a farm
in a hilly area. Range would be about 1 kilometer square.

Which XBEE 868 model can I choose to make this successful?


Allan



« Last Edit: December 31, 2012, 08:20:28 am by eagleeye » Logged

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A cheaper option would be the RFM22B  which I am presently experimenting with, it can also be set up as a mesh arrangement, but it has evidently   about a kilometer range anyway ( I havnt tested the range yet )

There is a library RF22 for it, with examples if simple one way transmission ( which I have working )   to a mesh network.

The Arduino should handle you power requirement with sleep mode, some of the experienced guys on this forum have got the quiescent current down to a  handful of microamps in sleep mode ( which will give you a life probably limited to the batteries shelf life ! )
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Hi
 Yeah the 433 mhz is a good option.. you mean it has automatic repeater
function built in? This means I can simply power up some rfm22s and leave
them repeat signals around blind spots? Thanks for the tip, I will study it
carefully.

I stil would like to hear what the Xbee Gurus say about my requirements.

I went to the WASPMOTE product web page. Seems they
have an impressive range of 'plug and play' solutions. however
its very pricey and my farmer has an end of life for this project
of 2 years.

http://www.libelium.com/products/waspmote/hardware


Regds
Allan


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Quote
I stil would like to hear what the Xbee Gurus say about my requirements.
More than half of your requirements have nothing to do with the kind of radio you choose. Sleeping an XBee is possible. Waking up the Arduino because the sleeping XBee received a broadcast won't happen, because sleeping XBees don't receive broadcasts.

Measuring light level is not something that the XBee is going to do. The Arduino is, but not while it is sleeping.

Quote
2. From a PC or other embeded board I would like to transmit a command to
all the 20 Arduino fios and get them to respond with the data.

4. The Ardunino Fios will be in sleep mode and wake up and transmit their data and go into  sleep mode
every 30 minutes.
You say that the data needs to be broadcast in response to the request for data. The Arduino and XBee have to be awake to receive that broadcast.

Before choosing hardware and sleep modes, you need to get your requirements straight.
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Quote

2. From a PC or other embeded board I would like to transmit a command to
all the 20 Arduino fios and get them to respond with the data.

4. The Ardunino Fios will be in sleep mode and wake up and transmit their data and go into  sleep mode
every 30 minutes.
You say that the data needs to be broadcast in response to the request for data. The Arduino and XBee have to be awake to receive that broadcast.

Before choosing hardware and sleep modes, you need to get your requirements straight.

Hi, I forgot to remove point #2. as I was typing the message.

My idea is this..

A. FIO should wake up every 30 minutes ( the XBEE should stay sleeping)
B. FIO checks for light, no light? goes back to sleep , if light detected FIO wakes up the XBEE and transmits
    puts the Xbee to sleep and goes into sleep mode.


Allan














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A cheaper option would be the RFM22B  which I am presently experimenting with, it can also be set up as a mesh arrangement, but it has evidently   about a kilometer range anyway ( I havnt tested the range yet )

Yeah, how are things coming along now with your problems from the other thread? Resolved.
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I understand XBEE 868 digimesh is a restricted export controlled product.
so I would like to avoid that as much as possible.

Check with these guys, I believe they are in Shenzhen,

http://www.seeedstudio.com/depot/index.php?main_page=advanced_search_result&search_in_description=1&keyword=beefamily

http://www.seeedstudio.com/depot/rfbee-v11-wireless-arduino-compatible-node-p-614.html?cPath=139_140
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Yeah, how are things coming along now with your problems from the other thread? Resolved.

I got the basic transmission going nicely, now busy with the display ( 1800 odd LEDs to wire up ) What a way to see the new year in :-)
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Sheesh, 1800 Leds, I don't remember that part, :-). 42 x 42? For my new years, I got my
2-line LCD with 6-buttons going, LOL. The example sketch, of course, didn't work properly.

Next to do the RFM stuff = JeeNode [433 Mhz RFM12], then we can compare notes. In
relationship to OP's problem, the first thing I plan to do is a range test.

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For my new years, I got my 2-line LCD with 6-buttons going, LOL.

Me too, perhaps we could have collaborated :-)

My ( 60 ) SAA1064 chips havnt arrived yet, so I might get a chance to check the range of the RFM22B tomorrow.

I see the FIO uses the 328 chip  ( like the Duemianova )  which the RF22 library writer reckons has not really enough memory for networking and mesh applications...... 
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@boffin, this is kind of poaching on this thread [although it's kind of run its course
anyways], but I've spent the past couple of days being completely unsuccessful at getting
the JeeNodes with RFM21 transceivers to talk to each other. I can get the RF12demo to
load and run on the Arduino, but cannot make RF comms between the 2 boards.

Got any suggestions or code I could try?

I've looked at maybe 100 pages on the jeelabs website, and downloaded everything I
could find, but so far, no luck. That site, I think, is the worst organized site in internet
history. Plus, almost nothing I could find updated in the past 3 years, and most of the
links go to 404.
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@  oric_dan(333) 

Well that Jeenode is a bit confusing when I look at the schematic,  it takes in  BAT+ ( presumably 5v )  and feeds a 3v3 regulator that runs the micro and the RFM21 radio module.

But all the ports and FTDI connectors are fed with 5v and there is no level converter on their data lines ?

Or am I missing something here ?

I am using the RFM22B  and I am converting the level with resistors at the moment, which is working on the proto.

I only got as far as sending sinplex data with this so far as I am on a rush job and need to get the LED side tested before tidying up the comms.
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Actually, all the busses on the JeeNode pcb are run off the 3.3V v.reg., including the
Arduino chip and RF12, so no level shifters are needed there. The FTDI cable can
provide 5V to the Rx,Tx pins, but I put in 1K series Rs there to deal with this
problem.

So, the Arduino works fine, and I can load and run sketches ok. The RF12demo works
and you can use SerialMonitor to configure the RF12 module ok, but I cannot get 2
JeeNode boards to communicate via the RF link. I tried loading node and group
values, etc, but still no luck. Sounds like yours just worked ok from the box.
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Hmm.   if you are not using any of the "ports" that supply 5v but communicate with 3v3, there shouldn't be a problem .

I have only used the RFM22B simplex mode so far , with the RF22 library from mikem , and it seems to work OK.......

I dont know about working out of the box :-)      I am still new to all this and found the library daunting !
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