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Author Topic: Looking for developer: XBEE + Arduino Ethernet gateway  (Read 1468 times)
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Job posting: http://jobs.arduinoexperts.com/jobs/xbee-arduino-ethernet-gateway/

I’m interested in having a gateway designed that relays all data appearing on the serial port of the arduino to a server online via Ethernet.

An XBEE module will be connected to the arduino as well as an ethernet shield.

Requirements:

DHCP – On power up the arduino needs to use DHCP to allocate an IP address from whatever router it is connected to

Serial TTY input – the arduino needs to be monitoring the serial port in realtime and sending all data it receives from the XBEE to a specified server on the internet via the arduino Ethernet library

the arduino may need to buffer incoming data so that nothing is lost.. need more insight into this..

I’m looking for a developer that can write the arduino code required to make this happen .. it’s a pretty simple application, I just need it to be optimized to handle the possibility of receiving data from many XBEE sensors at the same time and not dropping any resulting data in the process..
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Some questions, if I may.

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An XBEE module will be connected to the arduino as well as an ethernet shield.
Which XBee module? Which ethernet shield?

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the arduino needs to be monitoring the serial port in realtime and sending all data it receives from the XBEE to a specified server on the internet via the arduino Ethernet library
What is sending the data? How much? How fast?

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the arduino may need to buffer incoming data so that nothing is lost.. need more insight into this..
The Arduino doesn't have a lot of space for a buffer. If the data comes in faster than it goes out, any buffer will eventually fill up. So, the amount of incoming data is critical. How many bits/bytes/whatever per second/minute/hour/day/whatever?

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I’m looking for a developer that can write the arduino code required to make this happen .. it’s a pretty simple application, I just need it to be optimized to handle the possibility of receiving data from many XBEE sensors at the same time and not dropping any resulting data in the process..
Ah, a new requirement snuck in at the very end. The new one makes the job much more complicated. It may not really be that simple.

Where are you located? How will the testing be performed? Need date? Compensation?
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Sounded easy right up until

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from many XBEE sensors at the same time and not dropping any resulting data in the process..

______
Rob
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Rob Gray aka the GRAYnomad www.robgray.com

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Thanks for your responses.. I called Digi yesterday to ask about how the XBEE itself handles the problem of many nodes.

He said it should be able to handle 'thousands' of nodes.. but I asked what happens if a whole bunch of those start sending at the same time - he said he would get back to me.

This may not be a problem at all .. if I have 500 nodes with a heartbeat of 5 minutes... I think there wouldn't be too much overlap in communications
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Assuming the XBEE doesn't handle clashes...

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if I have 500 nodes with a heartbeat of 5 minutes
Yes but when the frequencies of two or more "beat" the transmission will clash for a long time and the more accurate the timing on the nodes the longer the transmissions will be corrupted.

Even a single corruption will blow your reporting out to 10 minutes, if the nodes are in sync that could wind up being hours.

You could add a random element to the transmission timing on all nodes.

______
Rob

 
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Rob Gray aka the GRAYnomad www.robgray.com

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