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GPS died, could XBee's x-mit power have killed it? — Parallax Forums

GPS died, could XBee's x-mit power have killed it?

MikeDYurMikeDYur Posts: 2,176
in Accessories
Not sure what happend, I pluged in the radio with all my other boards in place. All boards were sending data for a couple of minutes, then I noticed the GPS had no data on my remote recieving end, I went into my shop room to see what the problem was, no blinking green light. I brought the board out and hooked it up to another Propeller, and still nothing. Could the power of the XBee being in such close proximity to the GPS (esentually back to back) burn out something in the GPS reciever? Everthing else is still working fine, I spen a lot of time including this unit in my design, I thought it was bulletproof, and gave more info than most other modules. Plus the battery back-up aspect too. I really like the unit, and hate to have to go to somethin else. inspected it closely, no signs of overheating, bad solder conections, all componants look normal.
My next step may be powering through USB, since I pulled the connector off, I'll have to solder some wires to it. The documentation says it has soft power on/off, never fiddled with it, could that of set itself off?
Upon power up the red and blue LEDs blink once momentarally, and the green LED lights when I touch the componants near it. The question is could I have burnt something out by my high power XBee?
XBee Recieve.jpg
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Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    This is by no means a confirmation that this happened, but I can say that many years ago I burned out many receivers in the proximity of my CB radio, which pumped out enough power to overload the input receiver on anything too close to the antenna. And a GPS is designed to pick up a very low-power signal coming from orbit, so you'd think the receiver sensitivity would be pretty high. But, given that, you'd also think that they would protect the receiver inputs from overload like that.

    Perhaps the GPS module is defective? Or perhaps static? The world may never know. :innocent:
  • MikeDYurMikeDYur Posts: 2,176
    Thanks Chris,
    You didn't give me much hope after reading your CB story, I spent considerable time modding this into my project, and it was a sensitive reciever, I will tinker with it a little, and try powering it through USB. If it was the XBee, I'm going to have to weigh the options, can't go through another GPS, that's costly!

    Thanks again.

    Mike Y.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    Mike,

    A big difference with my CD was the amount of watts it was transmitting. The XBee Module is only a fraction of that. I just wonder based on the sensitivity of the receiver circuit and the proximity if it is enough. But then I have seen RFID tags fail for no apparent reason but have gone through X-Ray scanners at airports. Yet I am told others survived. It seems very hard to quantify.
  • MikeDYurMikeDYur Posts: 2,176
    Here's a pic of the close proximity I talked about. Looking over the schematic now, and if it wasn't for the USB circuit, this would be a 3.3v device. I took a close look at the board for a broken connection, that passed. Next I wiil power it alternatively to see what happens. No smoke, no smell, no lights. I'm bummed.

    Where do you live and how many years ago was that. I had television interference that I couldn't figure out. Maybe it was you practicing a little skip.
    XBee vs GPS.jpg
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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    1988-1989 in Schenectady, NY. I was keying up my CB (with a linear amplifier) and interfering with all the TVs within a block. But I damaged a receiver I had sitting nearby and didn't realize what happened until some time later. Apparently the output from the antenna was too much for the receiver's input stage and smoked it. Ever since then I've been wary of high-power transmitters near anything with sensitive electronics.
  • MikeDYurMikeDYur Posts: 2,176
    Chris,
    After looking the schematic over I figured it was a waste of time supplying power through USB, but I did it anyway. Checked for 3.3v @ the LINX module pin 12. The problem is under that little metal cover, and beyond my control. Well my temporary backup plan is a PMB-648 with a patch antenna, darn I could have at least bought the PMB-688 with exsternal antenna. I am going to see if this holds up on my platform, if not, design changes will have to be made. I have heard of recommendations here for GPS's, time to look for a new one.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    The GPS Module you are using. I found a few of those in my parts bins.
  • MikeDYurMikeDYur Posts: 2,176
    Chris Savage wrote: »
    The GPS Module you are using. I found a few of those in my parts bins.


    Have one with the external antenna? Even at that, I wanted to know #satellites. And I'm considering going off board with the GPS anyway, rather than try to retrofit another cable, one to manny holes now. And I still need a top board over it. Though there is nothing stopping me from taking it to the top board. But if I fry it where it's at, things become academic from there.

    Did you ever like the PMB-648?

    Thanks for thinking of my situation.

    Mike
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    #28505 is what I was referring to, however I may have some PMB-648 and PMB-688 as well. I have a whole drawer full of GPS receivers/modules from when I was testing them.
  • MikeDYurMikeDYur Posts: 2,176
    Wo,

    I sure would be willing to try another, this time shielded by another board, just in the process of changing code.

    What can I get one off of you for?

    If your willing to seperrate from them.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    If you're in the US, just shipping. I could make it easier if you're going to be ordering anything from Parallax this week I could add it to your package.
  • MikeDYurMikeDYur Posts: 2,176
    Chris Savage wrote: »
    If you're in the US, just shipping. I could make it easier if you're going to be ordering anything from Parallax this week I could add it to your package.


    Very generous of you Chris, unfortunately I got caught up W-Ms BF deals, and bought a new phone. So next month's allowance is used up. All I could really use right now is some components, and not nearly enough to take advantage of the free shipping offer. But that is not unusual, I have poor timing.
    Had to jump on the phone deal at $150.00 off, of what my wife payed for hers a little over three weeks ago.
    If you still are willing to do that for the price of U.S. shipping, I may be able to talk the wife into some capacitors and LEDs.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    Well, I will send myself a note home to pull it and bring it into the office just in case.
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