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Old Jun 03, 2015, 08:32 PM
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I appreciate that tip Van, I'll certainly check it out. I don't recall seeing the Safe X/Y settings, where is that?
Also, there seems to be some faint horizontal lines extending across the screen from each reading, any idea what might be causing this? Not sure if this is related or not but might be a clue. If the menu has been on the screen for a while, once closed, there is fairly strong image retention that takes 10 secs or so to disappear.
Thanks
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Old Jun 03, 2015, 09:06 PM
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Quote:
Originally Posted by crashnless View Post
I appreciate that tip Van, I'll certainly check it out. I don't recall seeing the Safe X/Y settings, where is that?
Also, there seems to be some faint horizontal lines extending across the screen from each reading, any idea what might be causing this? Not sure if this is related or not but might be a clue. If the menu has been on the screen for a while, once closed, there is fairly strong image retention that takes 10 secs or so to disappear.
Thanks
1) I think the Safe X/Y is in the OSD settings menu. Just look for it, you'll find it.
2) The 'smearing' has to do with mis-matched impedence from the FPV camera...some smear a little, some a lot, some not at all. There's a modification you can do to eliminate most/all of the smearing by changing out a resistor on the DOSD. I wouldn't recommend trying it yourself if you aren't surface mount repair experienced.
3) Image retention has nothing to do with the DOSD, but everything to do with your display device. You can add a resistor in the video out line to reduce the intensity of the overlay if needed.
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Old Jun 03, 2015, 11:57 PM
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I won't be changing the resistor on the board. I just read page 946 and saw Daniel's recommendations. I'll try the resistor on the video line, same as you mentioned. I appreciate your quick replies and help.
Thanks
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Old Jun 04, 2015, 05:28 AM
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I had the same line issue. I used DOSD+ v2 along with Attitude V2 and the FatShark 600 TVL camera. It appears that the DOSD has issue with this camera, apparently it's a question of video level.

No resistor mod worked for me. I even tried with potentiometers with different ranges in order to try for the best value. Tried this in different configurations (serial, parallel). Nothing ever helped to reduce this issue.

My own personal conclusion is that the black level outputted from the DOSD, along with the white level of this specific camera, makes a too high amplitude that somehow create those display issues on some receivers or displays.

I solved this by activating the "Disable Text Border" in the OSD settings, which obviously reduces the contrast of the text.
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Old Jul 06, 2015, 12:11 PM
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I found these instructions after I installed my ublox NEO -6M GPS. It is installed with the TX line connected.

I'm getting strange behavior and it might be related to the TX line, but I wanted to confirm before pulling apart my wing to get at the electronics (they are somewhat buried).

My GPS (GY-GPS6MV2 - NEO-6M-0-001) was configured using the u-center app for NMEA and 115200 baud. My initial tests and first flights after the change were successful. The next weekend, DOSD didn't seem to recognize the GPS. The boot sequence showed ublox, but at 9600 baud. I disconnected/reconnected the system power several times, with no change.

When I got home, and tried it again, it connected at 115200 baud

Is there some configuration I'm missing (other than disconnecting the TX line)? I still find it strange that TX needs to be disconnected. Does the DOSD send instructions that potentially reconfigure the GPS?

Thanks

Quote:
Originally Posted by DenisM View Post
I fly successfully with Ublox lea-6M (not 6H), also ordered from Hobbyking.

It will not work out of the box with DOSD. If simply plug it in you will have slow lock if any, slow update rate if any. Do not fly before the following is made:

1. install u-center (app download from u-blox web site) on the PC.
2. use FTDI USB board to connect your GPS as serial port on PC.
3. using u-center configure your GPS unit to output NMEA sentences. Disable UBLOX protocol output.
4. in u-center set serial port of GPS to 115200 baud. Max update rate is 5Hz.
5. in u-center save all changes to the GPS chip.
6. Feed cable thru the small ferrite ring 2 turns is usually enough. Place ring as close as possible to the GPS module.
7. when connecting GPS to the DOSD _do_not_connect_TX line on the DOSD header. This way DOSD can read GPS, but can not write to/configure it. If you leave TX line connected and power DOSD it will wipe your programming in GPS. Start over from #2.

DOSD on the boot detects GPS as UBLOX and port speed 115200.
Locks outdoor in 30 seconds. HDOP 0.9, 12 sats GPS is under the foam cover of X-8. Rock solid position detection. No GPS issues many dozens flights.

No more MTK for me, especially after these are just $20 piece.
I fly u-blox on the plane with DOSD and on Arducopter with APM on multirotors.
Ardu favors ublox due to the precision. We do not need 10HZ update rate.
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Old Jul 06, 2015, 01:55 PM
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Exactly. DOSD configures UBLOX GPS in some way which prevents it from properly working. It was not a problem with MTK GPS modules.
That is why for UBLOX I suggest after configuring with uCenter leave DOSD GPS TX pin float.

Quote:
Originally Posted by tonyyng View Post
Is there some configuration I'm missing (other than disconnecting the TX line)? I still find it strange that TX needs to be disconnected. Does the DOSD send instructions that potentially reconfigure the GPS?

Thanks
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Old Jul 06, 2015, 02:26 PM
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Thanks. I'll give that a try

Quote:
Originally Posted by DenisM View Post
Exactly. DOSD configures UBLOX GPS in some way which prevents it from properly working. It was not a problem with MTK GPS modules.
That is why for UBLOX I suggest after configuring with uCenter leave DOSD GPS TX pin float.
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