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Parallax GPS problems — Parallax Forums

Parallax GPS problems

MinimumWageMinimumWage Posts: 72
edited 2008-09-08 15:33 in General Discussion
Hi,

I am wondering if anyone else has had any problems with the Parallax GPS module and can offer some advice. I have one that has been working fine for months on a robot but now just will not achieve a lock. The red light just flashes constantly. Sometimes if I leave it outside for an hour or more it will finally get a lock but it rarely manages to maintain it for more than a few minutes. I have an old handheld Garmin unit that I set right next to it and it comes up in 2-3 minutes every time. The antenna and SX processor on the Parallax unit feel fairly warm to me. I don't know if that's unusual or not. Has anyone else ever had anything like this happen?

Thanks in advance,

Mike

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-09-06 20:32
    Mike, how are you powering the Parallax GPS module? Where is it connected on the board? What is the power source?

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    Chris Savage
    Parallax Engineering
  • MinimumWageMinimumWage Posts: 72
    edited 2008-09-06 20:43
    Chris,

    My robot has a custom board, but power to the GPS comes from a +5VDC regulated circuit (fed by a 7.2V battery). I've also tried it from a BOE, connecting it to the servo header blocks with the jumper set to Vdd.

    Mike
  • MinimumWageMinimumWage Posts: 72
    edited 2008-09-06 20:48
    Chris,

    One other weird thing is that it seems like the GPS LED is blinking at different rates. Normally it flashes once per second when it's waiting for lock but I just noticed that when I move it around it sometimes speeds up to 2x that rate. I've never seen that before.

    Mike
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-09-06 21:28
    My questions on the power were because one customer was sure he was only giving the unit 5V when in fact he was sending 6V into it. His board sent VIN to the servo headers. As for the blinking, when the GPS has locked onto two satellites the LED will start blinking faster to let you know that is close to being valid with the signal.

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    Chris Savage
    Parallax Engineering
  • MinimumWageMinimumWage Posts: 72
    edited 2008-09-06 21:42
    Chris,

    I checked my custom board with a meter just to make sure it was +5VDC and that the ground was ok. I didn't know about the blinking rate, thanks for the info. My unit just can't get a lock on more than two satellites for some reason. Should the antenna feel warm to the touch?

    Mike
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-09-07 02:15
    A little warm perhaps...have you contacted Tech Support?

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    Chris Savage
    Parallax Engineering
  • MinimumWageMinimumWage Posts: 72
    edited 2008-09-08 15:33
    Chris,

    Thanks. I sent tech support an e-mail this morning detailing my problems.

    Mike
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