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Forum Index : Microcontroller and PC projects : UBLOX NEO-7M-C
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palcal Guru  Joined: 12/10/2011 Location: AustraliaPosts: 1989 |
I purchased one of the above GPS modules hoping it would be more sensitive indoors. The clock I have fitted it to was working fine with an EM-408. I changed the baud rate to 9600, the problem is it is receiving the GPRMC part of the sentence but does not receive a valid record instead of receiving A it keeps receiving V. I know WhiteWizard uses them and sells them. Can any one help? Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| viscomjim Guru Joined: 08/01/2014 Location: United StatesPosts: 925 |
Hi Palcal, I purchased a unit from WW, I think it was a 8M, that has the connector to attach an external antenna. Even though I used the unit indoors, it worked very very well. I never put the antenna outside and it picked up a few satellites easily. I'm not sure if your application can use an external antenna though.... |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2934 |
"palcal, From the title of your thread, it seems like you're trying to use the UBLOX-7M; but from your post it sounds like the EM-408 is the one causing you to receive 'invalid records'. Please can you clarify which GPS module your referring to when you switch to 9600 - and have you tried both (and if so, are they both giving the same result?) WW |
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Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3285 |
You did not say how long you waited for the lock. When a module is first turned on it must download details of the satellite's orbits which are encoded on the GPS signal. To receive the full set of data takes 12.5 minutes and if there is a corruption in the signal it could take a lot longer. So, you could try placing it outside so that it has an uninterrupted view of the sky and give it half an hour or more. Geoff Geoff Graham - http://geoffg.net |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1989 |
I have problems with the UBLOX-7M. I ran for about an hour but indoors near a window. I will put it outside and see how it goes. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1989 |
Well I left it running outdoors all day and still no result. I stopped it and ran for another hour when I got home still no go. I put a print statement in to print arg$(0) and arg$(2) (using Geoff's GPS code) and keep getting GPRMC V if I revert to the EM-408 all is OK. I'm running it on 3.3v I tried 5v but it seemed to get a bit hot so reverted to 3.3v Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2934 |
I seem to remember that for a UBlox, there was a different command that needs to be sent - or possibly a different 'search' character that needs to be checked for.I could not get Geoff's sample code going initially but soon fixed it with just a simple change. I don't have time at the moment,but if someone can check the data sheet then I think this will resolve Paul's issue. If I get time in a few hours I will take a look. WW |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2934 |
I remember it was something to do with looking for 'GPRMC' I had to change this (from Geoff's code): DO
GetGPSRecord ' get a GPS record LOOP UNTIL arg$(0) = "GPRMC" ' we only want the RMC record into just looking for 'RMC' on the right of arg$(0) IF RIGHT$(arg$(0),3)="RMC" . . . . . It is all about the 'string' coming out of the UBlox being slightly different by default. The Ublox is very configurable and could be set to output the 'usual' data format, but this was the easiest thing to do. I discovered it by simply hooking the GPS module to a USB-to-Serial module and opening up TeraTerm and looking at the outputted data. Hopefully this will solve it for you . . . . 
WW |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1989 |
@WW I tried that but still the same. I am receiving 'GPRMC' as arg$(0), but arg$(2) is always 'V'. I removed the battery hoping it would reset but that didn't help. I'm starting to think the module is faulty. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| plasma Guru Joined: 08/04/2012 Location: GermanyPosts: 437 |
Hi Palcal , Please try using the win software from u blox first. I have 3 ublox and every has forgotten his config. Even only one is working right after a days 😩 |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2934 |
To eliminate any 'issues', try viewing the raw data from the UBlox by connecting it a USB-to-Serial terminal and view in something like TeraTerm / Putty / HyperTerminal / MiniCom WW |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1989 |
I checked the current draw of the module and it is just over 200ma when it should be 35ma. I have contacted the supplier for a new one. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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