Replies to This Discussion

3D RoboticsPermalink Reply by Chris Anderson on October 4, 2010 at 9:57pm

I'm not following. What does "dump mode" mean? Is your LED sold on the GPS module itself?

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Permalink Reply by Paul Thompson on October 4, 2010 at 11:35pm

Sorry Chris, Poor choice of words on my part, Was meaning when the slider switch set for use with the CLI. Yes the GPS 3DFIX light is solid. I also have noticed on the GPS test on the CLI it was not picking up any sat. locks but still displaying Lat and long. Am I correct in thinking the GPS is actually getting a lock, hence the 3dfix led being solid, and perhaps an issue between the GPS and APM?

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3D RoboticsPermalink Reply by Chris Anderson on October 4, 2010 at 11:47pm

It always displays #sats = 0 (see sample data). That's not a problem. But the ABC LEDs should go solid.

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Permalink Reply by Paul Thompson on October 5, 2010 at 12:11am

Ok, at least its working in the CLI test, the ABC Led's are solid during the test, But still only getting the flashing ABC's during normal fly mode, Have had it on outside for over 30mins with no luck

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Permalink Reply by Paul Thompson on October 5, 2010 at 12:53am

Have just found out it will boot up correctly and get GPS lock showing on the ABC led's when powered from the USB with the slider switch set to fly. Just won't get the lock indication when powered via the reciever.

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Permalink Reply by Dave Whittington on October 5, 2010 at 4:55pm

Paul,
Does your SJ1 solder jumper #1 have a bead of solder on it? If yes, then the APM is powered from the ESC (via the throttle out servo connector). If not, then it isn't and another battery would be used to power the APM.
Do you get get all the LEDs on the APM as well as the flashing LEDs (that stop flashing after the IMU calibration) on the IMU board?

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3D RoboticsPermalink Reply by Chris Anderson on October 5, 2010 at 9:51pm

Paul, I have verified this bug and filed an issue. In the future, please file an issue yourself--the developers are not regularly monitoring the forums.

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AdminPermalink Reply by Thomas J Coyle III on October 5, 2010 at 5:19pm

Paul,

Measure the voltage between pins 1 & 8 on the MediaTek GPS. If it is less than 3.12 vdc then you are probably going to have problems getting a lock when on the UBEC.
You might try bending the little ears (tabs) on the back end of the negative plate of the battery holder under the interface board. Sometimes the ears get pushed into the positive plate of the battery holder and drop the regulator voltage below the allowable limit.
The regulator on my MediaTek was putting out 3.06 vdc and I was having trouble maintaining a reliable lock. After bending the ears away from the positive plate of the battery holder with my finger nail, I was able to always get a reliable lock. However, I sent the MediaTek GPS back to Jordi because 3.06 vdc is way out of spec and my other two MediaTek GPS/interface boards read 3.12 vdc or higher and always reliably lock.

Regards,
TCIII

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Permalink Reply by Paul Thompson on October 6, 2010 at 12:47am

The SJ1 is bridged with solder, and It has been running off the ESC's BEC. The lights on APM are indicating as they should and everything else seems to be fuctioning well when connected to the CLI. just cant get the GPS fix lights on initial powerup.

I measured the voltage between 1 and 8 pin on the MediaTek and I am getting 3.12v.
If I boot the board up and wait for the 3DFIX light on the MTek, I can then hit the reset button on the oilpan, let the it reboot and it will then show a GPS Lock. It seems to only not get the lock from an initial powerup.

Chris:
Thanks for doing that, I was not sure whether to do that or not, I will do so in future.

Cheers Paul

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3D RoboticsPermalink Reply by Chris Anderson on October 6, 2010 at 7:27am

Paul, thanks--that's good info for debugging. Sounds like it might be a timing error. I've noted your additional info in the issue report.

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Permalink Reply by Dave Whittington on October 6, 2010 at 5:16pm

As far as not getting GPS lock on the initial powerup, I almost always have that happen and I have a UBLOX. I am simply used to it now and just accept that I have to reboot once.

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Permalink Reply by Andre S on October 8, 2010 at 10:45am

I also did not get any GPS data (although the adapter board signalled a lock) and I tried about 10 times power cycling the board. Then I noticed that the GPS_MTK library has been changed (now AP_GPS_MTK) and that somebody had removed the delay in the Init function. Now I changed the init to contain
delay(500);
_port->print(MTK_SET_BINARY);
delay(500);
_port->print(MTK_SET_BINARY);
delay(500);
_port->print(MTK_SET_BINARY);
delay(500);
_port->print(MTK_OUTPUT_4HZ);
and (you can call me crazy for it) it worked on the first attempt.

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