Xbee project

Hi,

I've been asked to help with a project, but it involves radio comms (something I've not worked with before) before I say yes/no I'm looking for advice.

The project needs to transmit data from one arduino device to another arduino as follows...

  1. distance up to 3300ft (1000 meters)
  2. data transmission one-direction only.
  3. no requirement for security/encoding.
  4. relatively low data rates required (9600 or 19200 should be fine)
  5. good line-of-sight transmission.

I'm looking for relatively simple solution, the best option I've spotted seems to be Xbee and it seems I have to go for series ZB to get the range.XBee Pro 50mW Module with RPSMA (Series ZB)

Firstly, is an xbee series ZB the best option, and if yes, is there a simple get-you-started tutorial that anyone knows of?

thanks

I'm using a 60mw xbee on my project and it works brilliantly. Basically it sends all data over serial, good video here although I setup without an xbee explorer and used XCTU

xbee is the right choice but DO NOT use the one you found. It has 2.4GHz frequency and only reaches 1600m (that's best-case scenario). Use xbee pro-900HP with 900MHz (your country may have its own allowed frequency).

http://www.digi.com/resources/documentation/digidocs/90002173/Default.htm

Whilst you going to be assisting with a project on a subject you know nothing about, you will still be expected to get it right.

That means you need to be sure that the radio device you plan to use is legal to use in your part of the World, regulations on whats allowed vary a lot.

Remember that just because you can buy a particular device in one country, does not mean its legal to use there. Most places selling stuff do not care, they want to make money after all. The legal stuff is left to you.

Thanks davavastone, the video was useful.

DO NOT use the one you found. It has 2.4GHz frequency and only reaches 1600m (that's best-case scenario).

I only require 1000m, also I'm transmitting across a flat airfield with no obstructions, so I'm hoping that counts as best case scenario. I'm in the UK, so I don't think I can use the 900Mhz version.

Whilst you going to be assisting with a project on a subject you know nothing about, you will still be expected to get it right

For this project I'm an unpaid volunteer, that allows me to get it wrong :wink: If they want me to get it right, they have to pay me!

nd if yes, is there a simple get-you-started tutorial that anyone knows of?

That would depend on which XBees you end up getting (Series 1 are point to point, which is what your project needs) and how you connect them to the Arduino and what other hardware you get.

I'd get one of these:

for configuring the XBees. That beats removing the AtMega328 chip from the Arduino (if you can) so that you can use the Arduino board.

Do NOT drink the digi KoolAid. You MUST configure the XBees if you want any kind of performance from them.

  1. data transmission one-direction only.

Not true. The sending XBee will need to get data back, in order to know that the packet it sent was received and does not need to be sent again.

From what I've read/watched/learned it seems the complicated bit is just doing the configuration before use. Once it's configured it appears, it's a simple serial.write() to transmit, and serial.read() to receive. (both of which I've done before, albeit with wires)

Series 1 are point to point, which is what your project needs

Most of the series 1 seems to be low range, the one that isn't doesn't appear to be available in the UK. I think it will have to be series ZB.

data transmission one-direction only.

Not true. The sending XBee will need to get data back, in order to know that the packet it sent was received and does not need to be sent again.

This isn't something I need to worry about is it? My application only needs one direction communication, what the xbee modules do internally isn't something for me to worry about is it?

This isn't something I need to worry about is it?

No. You just need to be aware that two way communications is needed. That means that if the sender is a high powered model, for range, the receiver needs to be a high power model, too, to get the response back to the sender, that the packet was received properly.

I think it will have to be series ZB.

I'm not sure what this means. There are series 1 models (point to point) and series 2 models (mesh network). I can't imagine a different kind, or how they connect.

From what I've read/watched/learned it seems the complicated bit is just doing the configuration before use.

There is nothing really complicated about it. A series 1 radio can talk to one other series 1 radio. A series 2 radio is either a router/end device or a coordinator. There can be only one coordinator in a network. The series 2 can be set up to talk to one other device or to every other device in the network. The talk-to-one mode has priority on the network over the talk-to-everyone mode.

I'm not sure what this means. There are series 1 models (point to point) and series 2 models (mesh network). I can't imagine a different kind, or how they connect.

I think 'Series ZB' refers to ZigBee.....
www.coolcomponents.co.uk/xbee-pro-50mw-module-with-rpsma-series-zb.html

Or it may be a typo - there are other similar devices described as 'Series 2B'

The Xbee Pro 900HP is just the model number. It comes with a series of sub-models each with legal frequency for coverage of certain parts of the globe. You just buy the sub-model that is legal in your country.

I don't think you understood what I said. 1,600m for the 2.4GHz model is best-case scenario. What if it rains, animals roaming in the field blocking direct line of sight or knocking around your antenna, dust debris etc.? You can't leave it to best-case scenario if you want to keep your job/degree. You should plan for the worst that your money can buy. There is virtually little difference with the prices 2.4GHz vs 900MHz, maybe up to $10 differential per radio for the HP model with higher power and you also need longer antenna than the little stubs you get for $5. PaulS made a very good point. The underlying communication is two way so both radios need to be able to transmit strong signals.

liudr:
I don't think you understood what I said. 1,600m for the 2.4GHz model is best-case scenario. What if it rains, animals roaming in the field blocking direct line of sight or knocking around your antenna, dust debris etc.? You can't leave it to best-case scenario if you want to keep your job/degree. You should plan for the worst that your money can buy.

And not forgetting the local RF noise floor, which can have a significant effect as well.

Someone flying RC planes with video nearby (dissused airfield ?) that also use 2.4Ghz could have a major effect on comms.

If the transmitter/receiver is not mobile, or stays in the same heading, then use directional aerials.
Leo..

Wawa:
If the transmitter/receiver is not mobile, or stays in the same heading, then use directional aerials.
Leo..

Most directional antennas have implicit gain, so if used they they can exceed the legal limits of ERP.

For this user, and where in the World they may be, what are the limits ?