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TSL2561 and XBee
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Please be positive and constructive with your questions and comments.

TSL2561 and XBee

by DarkCurrent on Mon Sep 10, 2012 11:50 pm

Hello,

I am looking to connect the TSL2561 digital luminosity sensor (ID 439) to a standard XBee Series 2 as part of a remote garden sensor array at my school (outdoor classroom). The array will have temperature (10K thermistory ID 372) and moisture (DFRobot RB-Dfr-161) sensors as well, and all three sensors will be read by the XBee directly, which will then transfer the voltage readings wirelessly to another Xbee connected to an Arduino housed inside the school.

Anyway, I'm anticipating a compatibility problem as the luminosity sensor says it interfaces via an i2c connection. When I tested it with my Arduino it worked just fine as the Arduino has an i2c connector built-in. However, the standard Series 2 XBee I'm using has no onboard i2c connector according to Digi's documentation. On the other hand, my research shows that the XBee pro version does have an i2c connector.

So I'm assuming I'll need to purchase and upgrade to an XBee pro. Am I on the right track here? Can the TSL2561 connect directly to an XBee pro? I also came across some information that I could possibly make my own i2c connector chip and wire than to my standard Xbee. Not sure if that is possible, complicated or expensive. Any thoughts?

My goal is to make inexpensive and low power sensor arrays in the garden beds that can read the soil temp, soil moisture and light intensity the plants are growing with. If I have to switch each of my arrays to use the Xbee Pro, that's going to add about $10 per array, which will add up given the size of the outdoor classroom. However, if that's what I have to do, that's what I have to do. It'll be cheaper than putting an arduino in every array.

My other concern is the difficulty in programming the XBee Pro to read the two different digital inputs from this sensor (IR and full spectrum). Again, the Arduino can do this easily by simply connecting to a couple different digital inputs. However, I'm not certain if the XBee Pro has a single i2c connection or multiple (I was a little unclear based on the Digi docs alone). I don't want to buy a Series 2 Pro just to find out I can only connect either IR or full spec. If that's the case, I may look for a different light sensor or scale back the arrays with light sensors in them.

Any guidance you all could provide would be greatly appreciated.
DarkCurrent
 
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Re: TSL2561 and XBee

by jagrifen on Tue Sep 11, 2012 2:06 am

I've never tried interfacing an i2c device with an Xbee directly but I came across this site that may (or may not) offer some insight.
Good luck with your project!
JG
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jagrifen
 
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Location: Nashville, TN

Re: TSL2561 and XBee

by DarkCurrent on Tue Sep 11, 2012 5:31 pm

That's a great link you posted. It seems they're referring to the standard XBee Series 2 (like I have) when figuring out a way to directly connect the digital sensors that need i2c.

I dug around a bit more and found this:

http://forums.digi.com/support/forum/vi ... hread,8759

They discuss how the Pro model has the ability to directly connect i2c sensors. It seems there are 2 available pins as well, which would allow for both of the luminosity sensor connections to be attached as well.

If that's the case, being able to direct connect with a Pro model, I think I'll just budget the extra $10 there and save myself the hassle of the wiring/extra parts that the first article suggests to get a standard model to work.

Thing I'm not certain about is if the 2 pins mentioned (19 and 7) are true i2c connections or if only one or the other is. Any experience with these pro boards? I can't seem to find specific documentation that says exactly which pin(s) is/are i2c.

Thanks
DarkCurrent
 
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Joined: Mon Sep 10, 2012 11:25 pm

Re: TSL2561 and XBee

by jagrifen on Tue Sep 11, 2012 6:34 pm

Have you tried the posting to the digi forum? XBee can be kind of confusing...seems like they are capable of doing lots of things that aren't necessarily documented. Good luck!

JG

edit: You might look here too.
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Please be positive and constructive with your questions and comments.