Xbee setup with temp/humidity sensor
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Xbee setup with temp/humidity sensor

by d7x on Sun Mar 11, 2012 12:27 am

I'm trying to create a remote feed with temperature/humidity data from a DHT22 and BMP085 and was wondering about how to send data over the Xbee + sensors located outside to an Xbee inside attached to an LCD. I've taken a look at a lot of the tutorials and I understand how to put the Xbees together and update the units via a FTDI cable. What I'm still puzzled by is how to get the data from the remote Xbee to the indoor Xbee. It looks like I would connect the data out pin from the DHT22 to the RX pin on the remote Xbee and would connect the SDA pin from the BMP085 to the RX as well. Then, indoors, I would read data from the indoors Xbee on pin TX and would connect that to my LCD. Does it sound like I've got this correct? I'm not sure how to send data from 2 different sensors over a single Xbee and want to ensure that I'm doing this correct.

Also, I'd like to make sure that I'm ordering the right parts for this project.

Parts List:
1) Two Xbee modules - id 128
2) Two Xbee adapters - id 126
3) FTDI cable - id 70
4) power - not sure what type of battery pack to use
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Re: Xbee setup with temp/humidity sensor

by adafruit_support_bill on Sun Mar 11, 2012 5:55 am

The XBee modules can do simple digital or analog I/O, but both the DHT22 and BMP085 sensors require a microprocessor for communication. You could add an Arduino (or a Boarduino for a smaller, less expensive package) to the outdoor transmitter. You would connect the sensors to the arduino/boarduino (see the sensor tutorials for details) then connect that to the XBee adapter via serial.

A 6xAA battery pack with either alkaline or rechargeable NiMH cells should power this for a good long time.
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Re: Xbee setup with temp/humidity sensor

by d7x on Sun Mar 11, 2012 9:11 am

How would one know up front when communicating via Xbee modules whether their data output could be sent directly from the sensor to the Xbee or whether their output would first need to go through a microprocessor like the Arduino or Boarduino? For example, I might also want to add my TSL2561 and send back the Lux reading as well but I'm not sure what it is that would tell me that I need to first go through a microprocessor. Does the data need to be converted from digital to analog or is/are there another reason/s?
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Re: Xbee setup with temp/humidity sensor

by adafruit_support_bill on Sun Mar 11, 2012 10:37 am

The word 'digital' can mean different things. In the case of the XBee, the digital I/O pins can read and transmit the state of simple on/off types of sensors( contact sensors, motion detectors etc). In the case of the TSL2561 (as well as your other sensors), analog information is transmitted via a 'digital protocol' (I2C). The I2C protocol involves rapidly switching two digital pins in a coordinated pattern to communicate the data. A microprocessor is needed to decode that pattern into an analog value.

Any time you see an 'analog' sensor with a 'digital interface', it probably needs a microprocessor to interface with an XBEE.
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Re: Xbee setup with temp/humidity sensor

by The.Professor on Thu May 24, 2012 2:28 pm

I am trying to do something similar.

I have attached a pic (use scroll to see version 1 and version 2). Anyone know if I need to use a micro-controller for this setup? Am I missing something?

Thanks.
Attachments
Temp_Mockup.jpg
Temp_Mockup.jpg (39.75 KiB) Viewed 1114 times
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Re: Xbee setup with temp/humidity sensor

by adafruit_support_bill on Thu May 24, 2012 3:02 pm

You should be able to implement version 2.

Take a look at the Tweet-A-Watt project. You can ignore all the part about connecting it to the Kill-A-Watt, but the XBee configuration will be essentially the same.
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