The compass will cause these exact flight characteristics, and will not report abnormal readings if the compass orientation has been changed. This often occurs when landing gear has been changed/upgraded.
New and looking for pointers!
- Thread starter Yamasung
- Start date
I don't think the compass was changed to another position, right OP?
And it happened after a first successful flight with another battery. Why would the compass be off after changing a battery? There's no reason for that. My own experience make me guess that the quad wrote a new homepoint (and whatever nose position) in midair. Based on odd readings because of a sudden loss of current that homepoint may well be on the other side of the planet. I'm (almost) sure that's what happened in my case.
And it happened after a first successful flight with another battery. Why would the compass be off after changing a battery? There's no reason for that. My own experience make me guess that the quad wrote a new homepoint (and whatever nose position) in midair. Based on odd readings because of a sudden loss of current that homepoint may well be on the other side of the planet. I'm (almost) sure that's what happened in my case.
Did the compass get wet after landing the first time? A wet compass is also a way to get sudden misbehaviour.
Ok, quick recap to answer questions asked.
1. Took quad on vacation (had zero issues prior to this time), did compass dance prior to first flight and everything worked perfectly- tight hover, easy, responsive control, etc.
2. Second flight same thing except at end of flight, landing gear ticked fence, quad lost control briefly and skidded across sand/scrub, but I regained control and returned under stick control only having dropped camera. No apparent big deal.
3. Third time was the near disaster. I did not calibrate the compass prior to third flight, but did get home lock without issue. Upon attempting hover, it was not tight at all and wandered. The wandering wasn't bad and I could control it so I went ahead and flew until the battery switch. After switching battery I performed the compass calibration with no errors, got home lock and hovered again noting the same issue as before, but it seemed worse. This time I tried landing/powering down and once I got it back to the ground is when it powered up on its own and skittered under the cars, etc, etc.
I just got home from vacay so will be checking out the compass values soon. Other suggestions I've heard are: check for loose wires at the flight controller, perform an advanced IMU calibration (have not done this, is it difficult or self explanatory?), check battery terminal connections, ensure compass isn't wet.
All great suggestions and I am thankful for the help guys! That last one got me thinking...when I landed the quad before switching out the battery it was within 3 feet of a pool. Wasn't my first choice, obviously, but I missed the first warning and panicked a bit! It's possible that the compass got wet- I don't think it did, but can't rule it out either.
Will report back with what I find, if anything. Want to get this bird up and flying again without helplessly watching it fly away.
1. Took quad on vacation (had zero issues prior to this time), did compass dance prior to first flight and everything worked perfectly- tight hover, easy, responsive control, etc.
2. Second flight same thing except at end of flight, landing gear ticked fence, quad lost control briefly and skidded across sand/scrub, but I regained control and returned under stick control only having dropped camera. No apparent big deal.
3. Third time was the near disaster. I did not calibrate the compass prior to third flight, but did get home lock without issue. Upon attempting hover, it was not tight at all and wandered. The wandering wasn't bad and I could control it so I went ahead and flew until the battery switch. After switching battery I performed the compass calibration with no errors, got home lock and hovered again noting the same issue as before, but it seemed worse. This time I tried landing/powering down and once I got it back to the ground is when it powered up on its own and skittered under the cars, etc, etc.
I just got home from vacay so will be checking out the compass values soon. Other suggestions I've heard are: check for loose wires at the flight controller, perform an advanced IMU calibration (have not done this, is it difficult or self explanatory?), check battery terminal connections, ensure compass isn't wet.
All great suggestions and I am thankful for the help guys! That last one got me thinking...when I landed the quad before switching out the battery it was within 3 feet of a pool. Wasn't my first choice, obviously, but I missed the first warning and panicked a bit! It's possible that the compass got wet- I don't think it did, but can't rule it out either.
Will report back with what I find, if anything. Want to get this bird up and flying again without helplessly watching it fly away.
Yamasung said:
The compass is a picky ***** (sorry but it had to be said) and everything you describe sounds like the compass...except the Phantom taking off on it's own, that would suggest some type of interference.
The calibrations are just a simple click of the button, but you may have to force the calibration. The software will report that everything is fine, just calibrate anyway.
First step check that compass mod value so you can rule it out, and a good visual inspection of the compass itself.
Also are you sure you're performing the compass dance correctly?
lake_flyer said:
We just don't know, and often people won't include information because to them it seems trivial when in fact it's the smoking gun. Reading the OPs last post I'm a little concerned with the landing gear clipping the fence, but we'll have to see how it all plays out.
Yes you're right. Explaining things like this people often skip 'minor' details.
I should have read better also. Was already forgotten about the landing gear fence thing. A advanced calibration with the software (under Tools) should be done after such an event.
Good point.
I should have read better also. Was already forgotten about the landing gear fence thing. A advanced calibration with the software (under Tools) should be done after such an event.
Good point.
Ok- first bit of data- compass points (raw): X: 52 Y:85 Z:200 Mod:~1160
These appear to be normal based on the software explanation. I will proceed with the advanced IMU calibration anyway.
These appear to be normal based on the software explanation. I will proceed with the advanced IMU calibration anyway.
Next update- close inspection of compass and it appears to be completely fine and undamaged. Compass is obviously dry at this point (if it ever was wet). Checked battery contacts and no wiggle or questionable contact. Everything is nice and tight. Only thing left is to crack the shell and check for loose wires. Anything important to know before I proceed with this??
Yamasung said:
You seem a capable fellow, you should be fine. There are some Youtube videos that explain taking the shell off, would be worth watching.
I doubt you'll find anything under the hood, but if you do make sure to post a pic for us.
Yamasung said:
Finer than frog hair, it's looking more and more like you ran into some RF interference. I see a test flight in your future.
Thanks everyone and CarlJ for the quick responses! Charging batteries now and hope to get in a test flight today if I can get my post-vacation domestic duties taken care of :lol: ! If not, tomorrow for sure. Still need to pop the top too.
On another topic...I'm considering adding a Ground Station to my setup but am reading mixed info on compatibility without modification. I'm no electronics guy so when I hear that soldering is involved I automatically say "not for me". In reading about the GS from DJI's site it is clearly compatible with the NAZA-M v2. I watched the video on how to install the Bluetooth datalink and it looks quite simple, with basically a clip connection between the link and the v2 flight controller on the air end. When I posed the question to Atlanta Hobby, however, their reply was "The FC40 is not compatible with the 2.4g Datalink without modification. To make it work, you will need to install an additional PMU v2 to give the Phantom a canbus port." Again, non-electronics guy and still learning what PMU and canbus are, but can someone educate me here? Much thanks...and I realize I am all over the place with topics in this thread. Once the bird is well again, I will start new threads on topic!
On another topic...I'm considering adding a Ground Station to my setup but am reading mixed info on compatibility without modification. I'm no electronics guy so when I hear that soldering is involved I automatically say "not for me". In reading about the GS from DJI's site it is clearly compatible with the NAZA-M v2. I watched the video on how to install the Bluetooth datalink and it looks quite simple, with basically a clip connection between the link and the v2 flight controller on the air end. When I posed the question to Atlanta Hobby, however, their reply was "The FC40 is not compatible with the 2.4g Datalink without modification. To make it work, you will need to install an additional PMU v2 to give the Phantom a canbus port." Again, non-electronics guy and still learning what PMU and canbus are, but can someone educate me here? Much thanks...and I realize I am all over the place with topics in this thread. Once the bird is well again, I will start new threads on topic!
One last thing I wanted to ask everyone...if I set very low range limits, say 50m vertical and 50m horizontal, will this prevent a flyaway if the test flight goes awry or is it likely that they will just be ignored? I know it probably depends on what's or was wrong, but thought it might be an additional safety level...
Only when the homepoint has been recorded properly it will stay inside the box you set with the limits. The limits are the maximum distance from the set homepoint, not distance to the transmitter. You could even walk away 100m, still have connection and control but unable to leave the set box, if you set it to 50m.
So no, if it stays inside the box that is actually the proof that the GPS and compass functions are 100%, not the other way around.
With no proper GPS signal the quad will not stay inside the box.
It can be a handy feature when you know that obstacles are at a certain distance and you want to make sure you can't hit them.
So no, if it stays inside the box that is actually the proof that the GPS and compass functions are 100%, not the other way around.
With no proper GPS signal the quad will not stay inside the box.
It can be a handy feature when you know that obstacles are at a certain distance and you want to make sure you can't hit them.
Success! Followed all above advice except for opening the shell (watched the video and figured I'd run a test flight before peeling the stickers and pulling on wires) and everything was as perfect as pie today. Nice, tight hover even in a mild breeze, no loss of control or aberrant flight. Tested all modes- IOC, GPS, Atti., Failsafe, Tx switch-off- everything worked as it should and RTH landed the bird within a foot of where it took off. Only thing that bugged me a little was the flight time- getting maybe 12 minutes per battery in a mild wind. Also was rather shocked at the short time between first and second battery warning. The first time I didn't even have enough time to land as the quad was up so high at first alarm it went into second before I could get it down. Think I might adjust that in the software, if I can. And buy more batteries!
Now that I'm comfortable it was the compass likely coupled with interference (and know how to deal with it)...can anyone address my Ground Station question? If not I will post in another thread. Thanks to all for suggestions and helpful comments! This is definitely a fun hobby and I see a gimbals, GoPro and range extenders, etc. in my future...
Now that I'm comfortable it was the compass likely coupled with interference (and know how to deal with it)...can anyone address my Ground Station question? If not I will post in another thread. Thanks to all for suggestions and helpful comments! This is definitely a fun hobby and I see a gimbals, GoPro and range extenders, etc. in my future...
Glad that it all tested out fine.
Should give enough peace of mind to enjoy it to the full.
12min per battery is reasonable for default voltage gain settings. The batteries might format a little and after 20 or so flights they might give a minute more. I have the first level on 10.30V loaded and second on 10.00V loaded. Gives me about a minute between warnings. But I use a Lipo alarm that beeps (very loud) 1 minute before first level warning (I've set that to 3.5V per cel loaded which equals 10.50 for a 3 cell battery). That gives me about 2.5 minutes total to do a RTH (which I always do, it's the quickest way back home). Roughly enough to return from 300m out and 200m high (descending takes 80% of that time and I always make sure I already descended to a lower level well before the beeper).
Should give enough peace of mind to enjoy it to the full.
12min per battery is reasonable for default voltage gain settings. The batteries might format a little and after 20 or so flights they might give a minute more. I have the first level on 10.30V loaded and second on 10.00V loaded. Gives me about a minute between warnings. But I use a Lipo alarm that beeps (very loud) 1 minute before first level warning (I've set that to 3.5V per cel loaded which equals 10.50 for a 3 cell battery). That gives me about 2.5 minutes total to do a RTH (which I always do, it's the quickest way back home). Roughly enough to return from 300m out and 200m high (descending takes 80% of that time and I always make sure I already descended to a lower level well before the beeper).
Yamasung said:
Glad everything is working! What was the question on the Ground Station? I assume you'd like one, but that would require some big modifications.
