Sep 07, 2011, 09:22 AM
Registered User
mrdaction's Avatar
Thanks, I'm not feeling very good about myself right now. If I told you I read over those instructions a few times and got the impression that if you had the ppm stream that's what you needed but in the back of my mind I continued to think of the outputs. I should have known better. Anyway, I'm relieved this is behind me.

Thanks for the help.
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Sep 07, 2011, 09:41 AM
Eccentricus Magnus
Originally Posted by roypwee View Post
I have a few diagrams which shows where the ground comes from.

So which is the correct one?

DOSD Wiring Vtx and Cam to DOSD
DOSD Wiring Lipo to DOSD
DOSD Wiring Cam to DOSD
DOSD Wiring Vtx to DOSD

Actually. . ALL those diagrams will work, because, according to the diagrams, the connections to ground are not on the boards/components themselves, but at the pin that attaches the component to ground.

It's best to connect ALL grounds to the main battery ground, on a wire coming from the battery. . and NOT on the board at another pin that must transmit the ground across the boards circuits or runs to the battery supplied ground. Since all those figures have the ground being supplied at the input/ground pin of the component, this effectively properly grounds the circuits without a ground loop passing through a component, since the ground is merely continued along the same ground path/wire. . back to the battery.

Sep 07, 2011, 11:05 AM
Well, now that you know ...
Bigster's Avatar
Originally Posted by Vantasstic View Post
Yeah, the DOSD needs ground movement to know what's going on. Evidently if it doesn't get enough movement it gets a little lost. I'm getting into FPV quads and GPS use on them appears pretty tough to do. I guess if you have a mag sensor it helps the controller and GPS data to work right/better.

The GAIN is how the control reacts. If a gain is to low the stabilization system is slow to react. If to high it reacts to quickly. In AP use, a 'to low' elevator gain would result in a none responsive elevator and might crash into the ground before ever pulling up. To high a gain and you'd end up with the plane porpoising up and down and never settling into a controlled altitude.

The DOSD controlled attitude gain settings will only work when using an ArduIMU...anything else will require you to set the gain from the unit itself...hence why you want to be able to switch the stabilizer on/off in case you set the gain to high or to low.
I guess I still don't know - even with the FY-20, if the plane has low groundspeed, can the DOSD command it into the ground, since the FY-20 doesn't know the difference between the DOSD command and those from the sticks. Does anyone have experience with this setup?
Sep 07, 2011, 03:05 PM
Fly Like A Thing Posessed!
NightRunner417's Avatar
Hey, I had a little crash to concrete with my Falcon wing (yet another launch-crash!) and everything in the fuselage shot forward... I'm just really lucky I only have one damaged part and not EVERYTHING damaged because lol all the guts were everywhere. Problem is, my Dragon OSD is now completely unresponsive. The video is passing through from camera to OSD to VTX, but it is very dim and there are absolutely no readings of any kind from the OSD, even on startup. It's also getting hot to the touch when power is applied - some of the chips are painfully hot so I think they're dead. There were several bent pins on the headers and some of them were contacting each other, which is what I think did the damage. Either way, she is *out*. I need to know who to contact about sending it back to Dragon Labs for repairs, how much this is going to cost, etc.

Thanks for any help! I needs my baby back!

Rick NR417
Sep 07, 2011, 03:27 PM
Registered User
Firatp's Avatar
Very unfortunately my DOSD was past away like yours after my skywalker kissed ground.
I give you my deepest condolences
Sep 07, 2011, 03:58 PM
Registered User
Bandarra's Avatar
Hey everyone, any chance anyone knows Daniel Wee's email (I tried to send a PM but his inbox is full).

If they do can you please send me a PM with it?

Many thanks!
Sep 07, 2011, 04:04 PM
Team Basement-RC
Tracks's Avatar
Originally Posted by mrdaction View Post
Thanks, I'm not feeling very good about myself right now. If I told you I read over those instructions a few times and got the impression that if you had the ppm stream that's what you needed but in the back of my mind I continued to think of the outputs. I should have known better. Anyway, I'm relieved this is behind me.

Thanks for the help.
Hehe.. if only it were all behind you. Now you get the fun part of tweaking the autopilot until it works right for your plane. Test all scenarios with AP starting from above cruise altitude, below cruise altitude, above cruise speed, below cruise speed, destination upwind, destination downwind, and all combinations in between.
Sep 07, 2011, 04:20 PM
Fly Like A Thing Posessed!
NightRunner417's Avatar
Originally Posted by Firatp View Post
Very unfortunately my DOSD was past away like yours after my skywalker kissed ground.
I give you my deepest condolences
Thank you Firatp. The most painful thing is that this is only the second time I've ever had the OSD up in the air, and LOS both times (testing) so I never actually got to fly FPV with it. I should have known better than to do what I did, which was to increase the motor power on launch. Sure enough, I threw the plane and she rose too sharply and rolled over and nosed straight down into the asphalt I was standing on. Funny how a plane can hit SO hard from only a few feet up in the air. No damage to the aircraft - I had reinforced her with a lot of packing tape and she took it like nothing... very surprising after seeing big damage from the same thing before the taping. BUT, all the components including both lipo battery packs, OSD, DragonLink receiver, and both the HD and FPV cameras shot out and were either hanging by wires or laying right on the asphalt. I almost wish the FPV camera had been destroyed instead of the OSD, because it's half the price and I have a second one just like it! And just when I was SO close to my first OSD aided FPV flights!! I love wings, love how they fly, but boy do I hate launching them! I really need to work on that.

Rick NR417
Sep 07, 2011, 11:44 PM
Eccentricus Magnus

More baro sensor news

I've been doing some testing with a brand new DOSD (to replace the one I lost in the crash last week), and when I got to the Baro sensor installation stage, I started having some problems.

As most people know, it is POSSIBLE for the DOSD to "lockup" in the middle of a reboot in flight, if there is a communication conflict on the board between its on-board circuits and peripherals such as the Baro sensor and GPS. I was testing a Baro sensor that was unmodified, and sure enough, as I was commanding the DOSD to reconfigure the HOME location, about every 6th-7th time I'd get a locked reboot, with resulting locked servos and no way to re-initiate the reboot to clear the lockup.

If this ever occurs in the air, you WILL not have any controls!!!! The plane may fly in some sort of quazi stable manner, but your transmitter will be useless.

I then installed a Baro sensor with the D1 diode shorted with a piece of small servo wire wrapped around it's length, effectively shorting the input and output pins without having to solder it.

Two things occured. . first off, the boot up was much quicker than with the unmodified Baro sensor, and it was now impossible to initiate a lockup through resetting the Home location. . no matter how many times I tried. As well, in the type 3 HUD (diagnostics screen) the S-error count dropped from 70-90 per reboot, to less than 15-20, showing that the modified Baro Sensor was working better with the DOSD and GPS, and was communicating with less interference.

Then there is the comparison I did between the Baro sensor altitude and the GPS altitude. Once it stabilized (which took about 15 minutes), the GPS altitude held a consistent 211-215 meters of altitude, while the Baro altimeter was a bit more fickle. The unmodified Baro showed a decent 225m altitude at first, then stabilized at about 211-214m. Google Earth lists the spot as 213m of altitude (701'). The modified Baro sensor showed 325m at first, then climbed to 365-370m after it stabilized for the outside temperature. No amount of rebooting would change that altitude reading. . . . . .I reinstalled the 1st sensor, after shorting the diode, and got a reading of -45m (100' below sea level), which slowly changed as the Baro sensor cooled off and eventually reached 210-215m and stabilized at that reading (though it took 15 minutes to do so). . the difference on the 2nd baro was that my house was 73 degrees inside, and outside it is 61 degrees, and I could watch the temperature drop as the altitude reading increased. Happily, further testing with the now-modified Baro sensor showed its reboot was as stable and quick as it's sibling, which makes me a bit more comfortable installing both sensors into my planes now.

A couple of things. . on my BIG plane (the 50cc gasser) I was getting a glitch in the video every 25-30 seconds, which is now GONE with the modified sensor in place (and makes me very happy). . the 2nd things is. .why are these Baro sensors continuing to ship to customers with the diode still in place? I have not heard of one instance where the diode helped things perform better, and it seems that EVERY one is shorting the diode (at the risk of damaging the board). It seems that it's time to remove that piece from the design. . .and move on.

So, anyone getting the Baro sensing altimeter add-on for the DOSD .. my advice is to short the D1 diode before you ever even install it. I've seen nothing but problems associated with this component being in place, and everyone seems to be a lot happier without it. After that, be very scrupulous in testing it's actual altitude reading versus known location altitude, and make sure it stabilizes before flying to assure the AP holds the programmed altitude instead of something different.

And lastly. . given the very decent GPS altitude I was reading. . do we REALLY need the BAro/altimeter board in the first place? It does seem to make the plane a bit more aggressive in holding, and achieving, the desired altitude via AP control. . but the GPS altitude hold is pretty decent too. . . just something to think about.

Sep 07, 2011, 11:50 PM
Registered User
mrdaction's Avatar
Your scaring me, let me at least see the thing act like it wants to come home, like a wing tipping in my direction. those other settings sound like a whole other can of worms to me.
Sep 08, 2011, 12:19 AM
Eccentricus Magnus

Okay. . and now I am worried

I finish the last post. . go to the DOSD and plug in a freshly charged 3s pack. . and NOTHING on the screen. . just the video, no OSD, no servo movement, no bootup script. I unplug everything except power and video, flip the switch .. only video . .do this 5-6 times. . same result. . play with knobs on the TX. . same thing .. no controls, no nothing. . . . . .hooked up PC Commander and still nothing. . .

SUDDENLY it starts working. . . . . all servos happy, all readings in place. .

I'm gonna call an Exorcist. . .

Sep 08, 2011, 12:22 AM
Eccentricus Magnus
Originally Posted by mrdaction View Post
Your scaring me, let me at least see the thing act like it wants to come home, like a wing tipping in my direction. those other settings sound like a whole other can of worms to me.

If you are not using a baro altimieter sensor, don't worry about it . .if you are .. I strongly recommend shorting the D1 diode on the board to ensure no problems later.

don't worry . . .really. . it will be all right. 95% of problems with DOSD are user caused. .not the board itself. . .

Excuse me, I have to call a priest. . .

Sep 08, 2011, 07:14 AM
Registered User

At this point I am probably not going to answer personal e-mails except from a few people. I would rather you just ask your question here. No reason why it needs to be in e-mail.


p.s. <--- bona fide Anglican priest
Sep 08, 2011, 08:29 AM
'FPV'er...not a "LOS'er
Vantasstic's Avatar

I believe your Baro post only refers to the one from Andrejk. I also believe he has since updated his baro so the D1 issue is not an issue any more. I'm going to guess you had an older senser and not a newer one.

I have a DIYDrones/Sparkfun Baro and I did have to remove a couple of resistors on it. It's worked well for me. I think just about any baro is going to be more accurate than GPS altitude. I don't believe GPS was really designed with exact altitude calculating in mind...or at least not the 'civilian/hobbies' type GPS units.
Sep 08, 2011, 09:53 AM
Skint since 2000
ghost2212's Avatar

Got the dragon OSD hooked up on the bench

So yesterday I set up the Dragon osd v2 on the bench with the ppm encoder and everything plugged in . I left it for 15 minutes with the GPS pointing up through a velux window in our loft but it didnt even get 1 satelite.

Is there a problem or?



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