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XBee and Memsic 2-Axis Acc Connection — Parallax Forums

XBee and Memsic 2-Axis Acc Connection

drmynattdrmynatt Posts: 20
edited 2012-03-05 18:15 in Accessories
Hi group- I just purchased the KickStarts book and see several examples of connecting individual components. I would like to remote a 2-Axis Acc thru my XBee connected to my HomeWork STAMP Board, back to my ham shack so I can read the tilt of the antenna.

Is there a connection diagram to show how to connect the two together. I don't want to melt either by connecting it wrongly.

Thanks, and any help appreciated.

Dave

Comments

  • groggorygroggory Posts: 205
    edited 2012-02-12 13:48
    There are lots of tutorials, manuals, examples on similar things to this.

    My advice...draw up some schematics and post em up. We'll help you iron out your problems.
  • drmynattdrmynatt Posts: 20
    edited 2012-02-22 20:36
    Cool. Can you direct me to a schematic of a complete end-to-end system? I do not want to damage my XBees as they were gifts. Maybe a book of schematics for practical projects? I have two Parallax books but they didn't include enough specifics for a slow learner like me.

    Thanks, groggory

    Dave
  • groggorygroggory Posts: 205
    edited 2012-02-24 14:59
    drmynatt wrote: »
    Cool. Can you direct me to a schematic of a complete end-to-end system? I do not want to damage my XBees as they were gifts. Maybe a book of schematics for practical projects? I have two Parallax books but they didn't include enough specifics for a slow learner like me.

    Thanks, groggory

    Dave

    lol, SOOOO MANY resources out there.

    Post up exact parts and your application and I'm sure we could help you draft something.
  • TymkrsTymkrs Posts: 539
    edited 2012-02-25 00:23
    I'm more aware of how to hook the Prop up (though I'm still learning), but

    http://www.parallax.com/Portals/0/Downloads/docs/prod/rf/122-32450-XBeeTutorial-v1.0.1.pdf --> Page 135

    It looks like as you go down there's some code available as well. Hope this helps to point you in the right direction
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2012-02-29 15:36
    Hello,

    The Memsic has a 100Hz PWM type output for each channel which varies in duty cycle. there is no direct way to use the XBee to send this information back to the BASIC Stamp HomeWork Board. You would need another BASIC Stamp in between to send the duty cycle values serially from one XBee to another. The XBee is capable of transmitting other data, but not for dealing directly with a PWM signal in this manner.
  • groggorygroggory Posts: 205
    edited 2012-02-29 23:31
    Chris Savage wrote: »
    Hello,

    The Memsic has a 100Hz PWM type output for each channel which varies in duty cycle. there is no direct way to use the XBee to send this information back to the BASIC Stamp HomeWork Board. You would need another BASIC Stamp in between to send the duty cycle values serially from one XBee to another. The XBee is capable of transmitting other data, but not for dealing directly with a PWM signal in this manner.

    What about taking the Mesmic outputs, running them through RC filters so they'll approximate two voltages, then feed those into the XBee's built in ADCs. Then the remote unit can poll the XBee to get the voltage values.

    This would make for a simpler circuit on the remote end.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2012-03-01 08:21
    I suppose you could do that, however I am not sure what, if any effect there would be on resolution or accuracy and I have never used the XBee Analog inputs in that manner. Myself I would probably just throw another microcontroller at it, but trying new things and experimenting is always good, so perhaps you could test this theory and let us all know how it works. You might help many others in the future with your results.
  • drmynattdrmynatt Posts: 20
    edited 2012-03-01 17:27
    Okay, I can see that there is no ';easy' way to do it. On just a chance, is it possible to send the Parallax LCD RX lead over an XBee? Sounds too simple...

    Dave
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2012-03-02 00:10
    Dave,

    I don't see any reason you couldn't if the modules were sync'd up for communication and the baud rate matched that of the LCD Module. It should be as simple as sending serial data to the display.
  • drmynattdrmynatt Posts: 20
    edited 2012-03-02 11:35
    Chris et al- I ordered the book 'Stamps in Class 'Mini Projects', the Memsic 2125 and LCD 16x2 display to complete a project as listed in Chapter 3 of the project paper, 'Tilt with the Memsic Accelerometer''. I'm going to first try to dump the data to the PC for display and then the LCD and then, now that I have the XBee Base and Remote modules, a wireless setup.

    Wish you guys used PayPal.

    Dave
    KA0SWT
  • drmynattdrmynatt Posts: 20
    edited 2012-03-05 18:15
    The example most closely related to what I want to do is in Chapter 9, 'A Tilt Radio Controller for your Boe-Bot' in the 'Stamps In Class -Mini Projects' book. The example uses two 433 RF Transceivers and a Boe-Bot Robot.

    This is getting really too confusing and way too difficult to figure out. I cannot be the only person in the Parallax customer base who wants to send Mx2125 tilt data from a remote location back to a base station via XBee medium. In none of the books I have, so far, is there an example or description of how to interconnect these components.

    Is there a 'connectorized' schematic where the various pieces and parts can be connected together simply by identifying components?

    In case this sounds like whining, I want to state the obvious for the excellent engineers at Parallax. If a customer constructs and builds a circuit and it doesn't work, is it because (1) it is constructed wrong; (2) the software is wrong; (3) the component is faulty; (4) the customer damaged the component? I cannot, for one, to keep buying components every time my design doesn't work.

    If it costs money to build then why reinvent the wheel each time someone needs a circuit another has already built. If it isn't already in the Knowledge Base, what can be done to improve the base?

    I find it difficult to believe after three books, hours searching, and many (unanswered) emails to tech support, that no one has accomplished this design? No one?


    Okay; I'll go back to my reading.... complaint lamp is now Out.
    Dave
    KA0SWT
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