Thursday, January 17, 2013

U-blox PCI-5S - a cheap GPS module for your projects


 [Update] I have found the timepulse output!

The U-blox PCI-5S is the cheapest GPS module on eBay right now (although you have to buy an additional antenna).
At first glance it seems useless for microcontroller projects because it's a mini PCIe card, but as it turns out it has an easily accessible UART port that can be connected to a microcontroller.

Here's the pinout:
The USB device is a standard CDC ACM serial port.

RX/TX pins are a second (independent of USB) UART port running at 9600bps by default.

You can use u-center to modify the module's configuration, for example set the update frequency to 4Hz.

Happy hacking!

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46 comments:

  1. That's pretty cool, going to get one on Ebay. Could you tell me which antenna is best suited for these modules?

    ReplyDelete
    Replies

    1. According to the datasheet, any GPS antenna (active or passive) with a U.FL/IPEX connector should work.

      Delete

    2. Have you come across a source for those, please?

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    3. Look on ebay.

      I bought this one and it's working fine:
      http://www.ebay.com/itm/GPS-Ceramic-Internal-Patch-1575-42MHz-Antenna-20x20x7mm-e-/251215203055

      Delete

  2. Oh that really nice to here some extra deal.Now i'm going to buy this useful once..

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  3. PCI-E and Mini PCI-E edge connectors have both USB and PCI-E data on them. Looking at the pins used on the edge connector, I believe this card only uses the USB data. The other pins aren't used. I don't know how well links work here, I'll try anyway:
    http://pinoutsguide.com/Slots/mini_pcie_pinout.shtml

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  4. I just looked at the U-Blox site. Because the card available on eBay was made by/for Toshiba, there's no direct documentation for it on the U-Blox site, but the ones on eBay might be based on the now-discontinued 5S U-Blox GPS module. Here's a link to a page titled, "Previous generation GPS receiver modules." It's essentially a table comparing various no-longer-produced modules and their features. The feature I'm looking for is either a 1 (or 4) pulse-per-second (PPS) signal and/or the precision-timing feature--either or both of which can be used to make hyper-accurate GPS-discipined oscillators. It's not clear to me that the cheapies on eBay can do that. Does anyone have any knowledge of these devices who can comment?

    Thanks,

    Todd Carney

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    Replies

    1. It seems that this module does support a timepulse signal - it can be configured through u-center.
      Maybe the output is one of the other test points, I didn't find anything when I tested them, but the manual says the signal is only present when there is a reliable fix, I will try that again and report back.

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    2. I have found the timepulse output!

      Delete

    3. The firmware on the T modules is different, such that they spend more effort on the timing and less on the dynamics. You'll get good, but not great, performance from a non-T module.

      Are you on the time-nuts list?

      Delete

  5. Anyone have a source of these that ship to the Channel Isles?
    -A

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  6. Does it have a 1 pps output? If so, what voltage is it? (3.3. v or 5 volts)

    Thank you.

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    Replies

    1. It turns out it does, it's 3.3V like the rest of the module.

      Delete

  7. Nice find - any idea how much current this draws? I'm considering pairing one with a stellaris launchpad for a low power toy.

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  8. Replies

    1. I found 5 listings. On eBay.com, search "pci-5s".

      Delete

  9. I am wondering if the empty looking half of the pcb containing the edge connector could be sawed off for this kind of use.

    ReplyDelete
    Replies

    1. There is a high probability that it's possible, the u-blox product catalog shows a half size version of this card.
      But the PCB has more than 2 layers, so it's a mystery how the traces are routed in that area.

      Lots of people bought this card after HaD published my tip, maybe someone is brave enough to try it. :)

      Delete

  10. What would be interesting is whether this module supports the output of 'Raw' data output, which would allow more accurate (off board) position computation - L1 GPS can get down to around 1cm accuracy on a good day!

    Would be great for mobile robotics.

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  11. Nice hint, thank you very much for that.

    Do you know whether the card supports also PPS signal for time sync?

    Thank you

    McHa

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  12. Looking to make a GPS unit for my Nikon D800, anybody on here able to provide some assistance on such a project?

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  13. hello nice finding :) when i first saw the post on HDA i searched ebay and i bought one ~2 months later it arrived but i have some questions (cause i don't wan't to kill it :P)

    1. are the inputs 5V tolerant or only 3.3v ?
    2. does it require an external antenna ?
    3. the pictures show two test points for usb connection but i guess i have to provide 3.3v to power the device ?

    anyway thanks again for sharing

    someone said they couldn't find any listing on ebay i bought my from here http://www.ebay.com/itm/250866889973?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 - the shipping (at least for my country) is more that the actual module but is still cheaper than other gps modules

    ReplyDelete
    Replies

    1. 1.I don't know.
      2.Yes, you need an antenna with u.fl connector.
      3.Yes you need 3.3V, there is no voltage regulator on board.

      Delete

    2. thanks for the quick reply

      about the antenna do you think this will work ? http://www.seeedstudio.com/depot/embedded-antenna-ufl-for-gps-p-564.html?cPath=139_143

      thanks,
      Vlad

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    3. Yes, it should work, the module supports both active (like this one) and passive antennas.

      Delete

  14. Where do we find the place to change the frequency? that the only thing I cant find.

    ReplyDelete
    Replies

    1. You mean the update frequency?
      You need to install u-center software.
      From there select the "configuration view" and there you will have lots of configuration options, "RATE" is the option for changing update frequency.

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    2. Thanks, that was what I was searching for!

      Delete

  15. Hi Andrzej,
    I've just got the GPS from ebay last and had time to test it. It is working pretty well.
    Thank you also for updating for PPS pin, I wanted to search for it and I'm glad you got it.

    ReplyDelete

  16. I got mine in the post recently, and got it working. One thing that stumped me for ages was receiving a lot of "txbuf alloc" errors. I've fixed it now - it happens when the baud rate is too low for all the information to be sent. Setting the baud rate to 38400 instead of 9600 fixed it for me.

    ReplyDelete

  17. Hello

    I've just order it on ebay. But i'm not sure for the antenna.
    Maybe, the GPS internal antenna for the ipad 3 or ipad mini will be ok. It's very inexpensive on ebay:
    Like this one (1.39$)
    http://www.ebay.com/itm/New-GPS-Antenna-Signal-Flex-Cable-Repair-Fix-Replacement-Parts-For-iPad-3-3Gen-/280919335233?pt=Other_Tablet_eReader_Accessories&hash=item416818e141

    Or this one: (2.89$)
    http://www.ebay.com/itm/New-Replacement-GPS-Antenna-Signal-Flex-Ribbon-Cable-Fit-For-Ipad-mini-/140899956140?pt=Other_Tablet_eReader_Accessories&hash=item20ce4ab5ac

    But i'm not completly sure that the connector is a UFL (but it looks like on the pics)

    What do you think?

    ReplyDelete
    Replies

    1. I'm pretty sure they are both UFL.
      Take a look at iPad teardowns at iFixit - all the antenna connectors look like UFL.

      Delete

    2. thx. i'm gonna buy the cheapest one. i will inform you of the result of my test.
      have a good day!

      Delete

  18. Anyone cut this in half yet?? So tempting....

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  19. I messed up my module saving different settings. It will show sat's when attempting to read the config file, but otherwise shows nothing :( Can you post the default file for this module?

    ReplyDelete
    Replies

    1. http://pastebin.com/L38cqv8a

      Here's my config (not the default), serial port set to 115200 bps.

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    2. Thanks Emeryth, I found a default setting thing and it worked with that, but I'll keep your file. I think I got carried away clinking stuff.... clicked cold start and wasn't patient enough for it to find sat's.

      Delete

  20. Does anyone know how/if the module can be configured to output only GGA and RMC data ?

    ReplyDelete
    Replies

    1. Yes it can, through U-Center.
      I have not tried this, but there is a config option (MSG) for selecting which messages are sent over each interface.

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    2. is there any way to make the changes persistent over power on/off couldn't find any setting ?

      Vlad

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    3. The CFG configuration message lets you save settings to flash.

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  21. I should have payed more attention :) if anyone wants to configure this device to output only GGA and RMC data this are the steps to follow (using the u-center tool):
    1. go to view-> configure view
    2. select MSG(Message)
    3. from the dropdown box select which strings you don't want to output and deselect on which interface you don't want to output and remember to hit send after every change

    hope this helps someone,
    Vlad

    ReplyDelete

  22. Hi

    I have brought one from ebay, but can't get gps fix.
    Have happened to someone?

    ReplyDelete
    Replies

    1. Did you attach an antenna?
      Are you getting any satellites at all?

      Delete

    2. It's strange because in the ublox center show me the satellites conected and state of the signal. When disconnect the antenna can't see the satellites like should be.
      when i go see the data send on a console don't show any satellites connected.

      Delete

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