DragonOSD+V2 with RTH - Page 108 - RC Groups
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Jun 08, 2010, 04:03 AM
I love FPV!
Cralis's Avatar
Thanks... Just to check I understand, I connect my sensor to the battery first, and it registeres 0 load... OH.... I must connect the sensor to the battery first, and THEN to the OSD?
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Jun 08, 2010, 04:05 AM
Registered User
kempo's Avatar
Originally Posted by Cralis
Maiden flight of my DragonOSD+ - but nothing great in the flight. Didn't get more than 150 meters, I don't think. Was a bit windy, and the plane didn't want to fly nice.. Also, using an old camera, and it wasn't playing ball with my goggles, as the picture was way too dark... so it was a line of sight flight.. and pretty junk, as I am out of practise!

On the good side, the DOSD+ is by far the best OSD I have run so far! Loved it!! Everything was perfect. Home arrow was 100%, loved the accuracy of the altitude... menu easy to work... Lovely. Thanks guys for a fantastic product.

Cralis , can you tell me what kind of gps module do you have ? with/without battery?

Is there an option to change the UTC time to elapsed time ?
Jun 08, 2010, 04:08 AM
I love FPV!
Cralis's Avatar
I'm using this one. No battery, however, John (JMSTECH) mentioned a seller who does good 10Hz one for way cheaper, and I think they have a bettery too...

Not too sure about the UTC thing. I'm pretty sure there's a timer though.... I just have mine switched off.. I thought. Didn't even notice that UTC thing up there! I was more fixated with the data being displayed about the positioning. I previously flew a cheaper OSD, and was told my setup wasn't good enough for accurate GPS info.. However, the DragonOSD+ has excelled beautifully. Loved it. Same GPS module I used on the previous 'no working' OSD I tried. Very pleased.
Jun 08, 2010, 05:05 AM
Fly the Discombooberator!
magnetman's Avatar
Originally Posted by Cralis
Thanks... Just to check I understand, I connect my sensor to the battery first, and it registeres 0 load... OH.... I must connect the sensor to the battery first, and THEN to the OSD?

Yes, just connect the sensor to a battery supply, so you can measure the volts on the current output pin with no load. Is it a hall effect sensor?? if so it will have a standing voltage of about 0.6 V with no load. if it is a Flytron or one that uses a shunt resistor, then there will probably be very little offset voltage with no load. whatever voltage you measure, this will be the offset voltage in the DOSD menu selection.
Jun 08, 2010, 05:07 AM
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Cralis's Avatar
It's this one I am using.

Says, 'Very low zero current offset'.
Jun 08, 2010, 05:49 AM
Fly the Discombooberator!
magnetman's Avatar
Originally Posted by Cralis
It's this one I am using.

Says, 'Very low zero current offset'.
Yeah, that should be a very low offset. I have one but had problems with it (low output per Amp). Let me know how you get on. if it is working correctly, it should output about 30 Millivolts per amp load.
Jun 08, 2010, 06:29 PM
When in doubt, throttle out...
badlands's Avatar
Just received my FMP04 GPS today & gave it a go.

Wow! - John was right - GPS lock in seconds & works really well.

For $25 its a steal - order one now!

Jun 08, 2010, 08:05 PM
HD Hero Rocks!!!!!!
Wadsworth's Avatar
Is there a list somewhere of what the DOSD parameters names are short for, what they do exactly and what their default values are? I've seen the list of commands for the terminal control, but how about a detailed list of on-screen parameters?

At the moment I am trying to get autopilot calibrated and it would be nice to know what ALL of the parameters mean.

What does HIDP stand for? And what is it's expected range?
Does Max.Heading.Chang mean the amount it will allow home to drift before turning again?
What does RotLimit do exactly?

Here is a video example of what happens sometime with autopilot / return to home.
It generally turns and heads home pretty well when far off, but sometimes just keeps on going.
Home also drifts sometimes about 2-500 feet east.

I assume that my HIDP is low and I'm not getting a great GPS signal, but it would be nice to have a list of what everything does on the DOSD.

DOSD Autopilot Malfunction.wmv (2 min 5 sec)

I've adjusted a few things and am happy with the way it handles the plane, as long as it doesn't fly off into the distance.
The most recent adjustment was of the MaxHeadingChange from 45 down to 22.5 and it seemed to have made things worse.

I'm going to do some more adjustments but wanted to get some input while my batteries are charging.

Also, does the DOSD do any auto stabalization under normal flight, or only when RTH is activated?
Last edited by Wadsworth; Jun 08, 2010 at 08:22 PM.
Jun 09, 2010, 01:58 AM
Registered User

My guess is that some of the settings, in particular the gains, are too low and the plane isn't turning fast enough or is being over-powered by wind. Higher gains could help.

Jun 09, 2010, 02:07 AM
Registered User
JMSTECH's Avatar
Cralis.. nice flying man! You were in control if you asked me.. seriously very nice flying!!!

magnetman... I'm almost there with my current sensor

badlands... heyyy you must be making some commisions with thos GPS LOL!!! Seriously guys.. I don't make a cent off those GPS but works very well and helps makes our OSD look good, so why know encourage others to buy them? It's cheap enough and Ryan is a cool guy!

Wadsworth... been trying to make a PDF for the folks so you are not alone my friend.

Jun 09, 2010, 02:26 AM
I love FPV!
Cralis's Avatar
Thanks John.
I nearly lost it a few times... Turning with a cross wind was scarey... tried to flip the plane! And on all launches... I had full right aileron to try get me straight.

I'm wondering - is it possible the OSD was trying to assit me in anyway? I ask, as the rudder is going through the OSD, and there were times that I felt like I was trying to turn... but the tail wouldn't want to come around. Not explaining that right...

I use my right stick for ailerons... and I am using 2 channels for aileron right now. Rudder is a radio mix.. and it's 80% of my aileron input. (My rudder stick is used for panning the camera).

But when I turned, it looked like the plane would bank, but the tail would try go the wrong way... If I was turning left for example, the plane would bank left, but the tail would move left too, until the force of the turn overcame it, and then it would turn... If felt like maybe the rudder was going the opposite way? Is it possible I have some setting that is trying to keep the plane straight?

I really enjoyed the OSD. I saw it more on the reviews of the flight.. Didn't have much time to check it in these short flights...

Funny thing nearly happened: Because it was the first time I had a full sat lock... I had 'Autopilot (Home)' flashing on my screen. I thought that meant, 'If Autopilot engages, it will go home'. So, I nearly launched! hehe.. That would have been traumatic!

I then relaised, Oh! It's my switch! I have a 3 way switch setup, and for some reason, Top position is Autopilot... middle is normal OSD.. and bottom is Menu! I'll prefer it to be top = normal, middle = menu and bottom = autopilot. Will see if I can sus that out...

Jun 09, 2010, 01:54 PM
Registered User
HI guys,
Just a small video to show you my test for the DOSD Autopilot and RTH.Nice weather on that day and had a blast with thermals.Perfect day for long Range,but still need some tweaking ,before the final jump.I did the test with the default setting at start,then some minor change afterwards. I notice that the gain for the stabilization must be set quite low about 5-8 for the RTH to work ok else it will start to fight with the IMU.I did not increase the gain for the Turns cause i wanted to see how the osd handle the autopilot slowly.SIMPLY AMAZING ,ENJOY.

autopilot test.wmv (7 min 4 sec)

Is it Normal for the RRSI from the DLink to fluctuate like that,It's really making me nuts.I almost got 0 0/0 at about 600 m los.See the last part of the Video.I just want to be sure it's normal that it goes like from 100 to 0 quite rapidly.

Why does my artificial Horizon goes slant, even if I've powered up the imu with the plane completely level ,flat and initialisation completed.It was ok before ,see last post and video

Jun 09, 2010, 04:52 PM
When in doubt, throttle out...
badlands's Avatar
Nice video Anthony - where is that? Looks a great place to FPV.

Your RSSI levels are disconcerting, ive only has 2 flights with my DL & for most parts it stays at 100% (sometimes goes to 99%)

Did it calibrate ok?
Jun 09, 2010, 07:56 PM
Registered User

The RSSI could indicate one of three things, I think:-

1. Bad RSSI signal connection
2. You are getting some systemic high powered interference in the area and that seems to affect some of the channels used in the frequency hopping. Should be okay unless it stays at 0%.
3. RSSI calibration is off

The slant in the artificial horizon is due to the IMU confused by turns. This is where the IMU needs more work - something I'll have to get to once the other stuff has stabilized. It is also important that the IMU is calibrated as per instructions for the firmware 1.6e.

Jun 09, 2010, 08:11 PM
I love FPV!
Cralis's Avatar
Hi Daniel.

I am hunting for a resistor for my RSSI wire from the ThomasLRS RSSI Pin, to the DOSD+ RSSI signal input pin on the board. I'm told I can use a 1/2W 100K Ohm resistor as a buffer. Would that be OK? Would I get a good RSSI display on screen? And the construction method would be:

[LRS Rssi Out Pin] -------- 100k resistor---------[DOSD+ Rssi In Pin]

I will only connect that wire. The ground is handled via the ground from the PPM wire.

Is that right?

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