XBEE with propeller. Questions

Jon87Jon87 Posts: 14
edited July 2010 in Propeller 1 Vote Up0Vote Down
I'm attempting to make a remote temperature sensor using an XBEE connected to the prop which receives the temperature from an XBEE connected to a temperature sensor. I've attached a circuit diagram of what i'm doing incase that doesn't make sense. Ignore the lack of power and ground lines.

The questions i have are: is the XBEE capable of sampling the analogue signal from the temperature sensor and transmitting it to the reciever XBEE?

Do i only need 2 data lines between the prop and XBEE?

Do i need to connect each XBEE to a computer using an interface board to set them up?

Sorry that this post turned out to be aimed at XBEE more tyhan propeller.
800 x 600 - 13K


  • 3 Comments sorted by Date Added Votes
  • Gerry KeelyGerry Keely Posts: 75
    edited July 2010 Vote Up0Vote Down
    In response to your questions in the order in which they are asked

    yes·it is capable of adc but·you would have to check that temperature sensor range is same as xbee adc input or provide some form of conditioning circuit to make them compatibile.See

    http://www.digi.com/support/kbase/kbaseresultdetl.jsp?id=2180·for setting up adc.

    you need one data line for receive and one for transmit.

    Yes you need to set up the two xbees using a pc.Only needed once.


  • sylvie369sylvie369 Posts: 1,618
    edited July 2010 Vote Up0Vote Down
    This is the site that helped me to set up ADC on the XBee:


    Now, the Faludi setup is for I/O passing - it sets things up so that the voltage coming out of the I/O pin on the receiving XBee is the same as the voltage going into the I/O pin on the transmitting XBee. For the Prop to read it, you'd need to set up a simple RC time ADC circuit on the Prop pin you connect to the receiving XBee. It's also possible to have the transmitting XBee do the ADC itself, and send packets containing the digital version of the input voltage. I've had that working as well, quite a while ago, and it seems to work well, but you have to learn to parse those data packets, and there was always something in there that I didn't understand.

    Either way, you will need to send a reference voltage to the VRef pin of your transmitting XBee. I don't see that on your circuit diagram, though I see you didn't bother with the power connections either, so maybe you already knew about it.

    As for your other two questions, if you're setting up the XBees in advance, you'll need to interface them to a computer and either use XCTU or a terminal program to set and save the settings. You can do it instead through the Prop program on the receiving XBee, as part of your code, but that won't help you on the transmitting one, so you need an interface board and the computer interface anyway. Well, I suppose you could write another Prop program that did nothing but set and save the settings, and trade out the XBees in your hardware so that both had the chance to be written by the Prop, but it seems like the long, hard way to do it. If you're going to work with XBees you're going to want an interface board, and you're going to want XCTU (free download at digi.com). Get the Parallax USB XBee board (#32400, $20). It does everything.

    If you're using the I/O passing method, you only need one line to the Prop, one going through the RCTime ADC circuit to one I/O pin. If you're doing the other method, you still only need one Prop pin, coming from the receiving XBee's DOUT pin, UNLESS you plan to use your program to set the XBee settings, in which case you also need a pin going out to the XBee's DIN pin.
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