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This got ugly pretty fast
955 21 2018-8-9
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Tervist
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Was attempting to drain a battery as per a suggestion in a different thread I had started and things got ugly. I experienced the 'Downlink restored' messages and wasn't too concerned because I was indoors and knew I'd get interference. I was in Beginner Mode, had the prop guards on, and had the RTH set to current altitude.

I experienced a disconnect and the Spark went into RTH. All good. Except, instead of descending, it ascended rapidly and had a very unfortunate encounter with my ceiling. It bounced off it twice before crashing down onto the carpet, narrowly missing the coffee table. The only casualty appeared to be my ceiling which now has two sets of "Sparkprints" on it . We have a 4m vaulted ceiling in our living room. My question is, why did the Spark attempt to ascend when it was less than 3m away and approximately 1.2m off the ground? Per the manual, "The aircraft will land automatically if RTH is triggered and the aircraft is less than 3m from the home point". Why did the Spark ascend? I also notice in the log that the RTH altitude is set to 30m. Why is that messaging displaying if the aircraft is set to return to home at the current altitude?

The log is here. Signal loss occurred at the 6 minute 41 second mark. http://www.phantomhelp.com/LogViewer/FADMC4L8AM6CBT5ZWJUQ/







IMG_0357.jpg
2018-8-9
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Gunship9
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Shocked I am, that indoor flying could go wrong.  Odd that the Spark had enough GPS data to try to RTH.  Could it have been GPS signal reflections making the drone think it was far away from where it really was?  Stainless steel refrigerators filled with Sam Adams Boston Lager are well known to cause GPS reflection errors.


A Spark landing.gif
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Tervist
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Gunship9 Posted at 2018-8-9 14:55
Shocked I am, that indoor flying could go wrong.  Odd that the Spark had enough GPS data to try to RTH.  Could it have been GPS signal reflections making the drone think it was far away from where it really was?  Stainless steel refrigerators filled with Sam Adams Boston Lager are well known to cause GPS reflection errors.

Thanks for replying. I was trying to drain what was a possible faulty battery and just felt safer doing it indoors. I wasn't anticipating an error free flight but neither was I anticipating it to initiate a RTH and ascending.

The part of the floor directly underneath where the Spark collided with the ceiling is carpeted, so no there's no reflective surface where it decided to attempt the RTH.
The beer fridge is in a different room .  


2018-8-9
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Greg F
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Mine never has more than 4-5 satelites indoors and I have tried countless times to set a RTH but each time it fails.    Was your drone in GPS mode or ATTI or OPTI mode or was it going from one to another...  It may have been confused.    I find in OPTI mode, depending on the floor srface it can be either steady as a Rock or sway in any direction.     Having said all that I usually have issues when my BlueTooth is set to on, on my phone.    At least your drone isn't damaged.  
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Tervist
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Greg F Posted at 2018-8-9 15:57
Mine never has more than 4-5 satelites indoors and I have tried countless times to set a RTH but each time it fails.    Was your drone in GPS mode or ATTI or OPTI mode or was it going from one to another...  It may have been confused.    I find in OPTI mode, depending on the floor srface it can be either steady as a Rock or sway in any direction.     Having said all that I usually have issues when my BlueTooth is set to on, on my phone.    At least your drone isn't damaged.

I actually had it set in Beginner mode and it never went into ATTI Mode. It went from Beginner Mode to Go Home. I don't know how to determine if OPTI mode was ever engaged. Looking at the log, the satellite count was between 8-14. When I played the flight back using the DJI GO app it showed that the signal strength never dropped below 4 bars. Satellite count was 13 when I got disconnected. Signal strength was 4 bars. I'm stumped.

Aside from a few scuff marks on the propellers it looks fine. Tried a test flight outdoors, got a wifi interference error and landed the Spark immediately. Attached the OTG cable and had a smooth flight. Noticed a tiny bit of a wobble but I'm not sure if it was normal or due to today's incident. Will have to try a few more test flights.



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Greg F
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Tervist Posted at 2018-8-9 16:58
I actually had it set in Beginner mode and it never went into ATTI Mode. It went from Beginner Mode to Go Home. I don't know how to determine if OPTI mode was ever engaged. Looking at the log, the satellite count was between 8-14. When I played the flight back using the DJI GO app it showed that the signal strength never dropped below 4 bars. Satellite count was 13 when I got disconnected. Signal strength was 4 bars. I'm stumped.

Aside from a few scuff marks on the propellers it looks fine. Tried a test flight outdoors, got a wifi interference error and landed the Spark immediately. Attached the OTG cable and had a smooth flight. Noticed a tiny bit of a wobble but I'm not sure if it was normal or due to today's incident. Will have to try a few more test flights.

It would say in the Logs if it went into OPTI mode which uses the sensors underneath.   Strange one.     
2018-8-9
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Si_Co
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I’ve never had a good experience flying indoors, even though I’ve been really careful.  Minor crashes with ceiling and walls.  I just don’t attempt it anymore.  It’s just not worth it.
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Greg F
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Si_Co Posted at 2018-8-9 23:18
I’ve never had a good experience flying indoors, even though I’ve been really careful.  Minor crashes with ceiling and walls.  I just don’t attempt it anymore.  It’s just not worth it.

Maybe you live where there's too much Wifi Signal ( as in other people's Wifi) ..  Better to be safe and fly it outdoors..    My drone tends to drift a lot and you have to keep and eye on it..  
2018-8-9
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Weesel
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Servus!

I guess the GPS Signal strength indoors mostly depends on the type of building you are flying in. I would consider most american houses I have seen as wooden shacks. Decent GPS signal might be possible there. When I received Spark I had no Signal at all indoors. No windows and steel armored concrete seem to block signals quite effective...

Greetz
Weesel
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msinger
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"why did the Spark attempt to ascend when it was less than 3m away and approximately 1.2m off the ground?"

It looks like you hit this case:

Manual.jpg



"I also notice in the log that the RTH altitude is set to 30m. Why is that messaging displaying if the aircraft is set to return to home at the current altitude?"

That message is just showing the current RTH Altitude setting. It doesn't mean your Spark will always ascend to that altitude in all cases.
2018-8-10
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S-e-ven
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Thailand
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You should deactivate the RTH at current altitude, indoors!

It would direct land, if 3-20m away from homepoint.

If closer as 3m, it lands direct, anyway

hovering 30cm over ground and waiting, of course

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S-e-ven
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And it was more as 3m away:
13.0ft        ....  Signal Lost. Aircraft returning to Home Point

Just saying!
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S-e-ven
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I also notice in the log that the RTH altitude is set to 30m. Why is that messaging displaying if the aircraft is set to return to home at the current altitude?"

Because if further away as 20 meters, it would RTH on setted RTH heigh, anyway.
0-3m land, hover
3-20 either land/hover, if no settings (current altitude), or 2.5m high or higher (if current is higher)
20-xxxx RTH height

The question is, why it went up to 4 meters, like you say.
But the Sparks VPS altitude is 9ft2, just

I looked on google, are you sure with that 4m sealing in your house? ;-)
One story, plus roof, .....
2018-8-10
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Blellow
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Most of my crashes have been indoors.  There is way too many problems indoor.  GPS failure n wifi congestion is greatly increased. Nice I only drain batteries outside on the porch.
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DJT_MVSP
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For some reason, my spark ascends to the set altitude not 2.5 metres even when it's between 3m and 20m of the home point with RTH at current altitude turned ON
Has anyone tested this with their spark?
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S-e-ven
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DJT_MVSP Posted at 2018-8-10 06:53
For some reason, my spark ascends to the set altitude not 2.5 metres even when it's between 3m and 20m of the home point with RTH at current altitude turned ON
Has anyone tested this with their spark?

For quite some time (fw versions) not
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JimboHUN
Second Officer
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If it initiated RTH I think it must have tried to reach RTH altitude indoors...
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JimboHUN
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Sorry just read now the rest of the thread... so I said nothing new.
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Tervist
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msinger Posted at 2018-8-10 03:56
"why did the Spark attempt to ascend when it was less than 3m away and approximately 1.2m off the ground?"

It looks like you hit this case:

Thank you for posting this excerpt from the manual. I had read this after the incident and because was I so aggravated at the time it didn't register. Now that I am re-reading it with a calmer state of mind it seems this is what happened and the Spark behaved as it was supposed to under the circumstances. If my ceiling was a mere inch or so higher it would have been a non-issue. But still a good lesson learned. Thanks!
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Tervist
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S-e-ven Posted at 2018-8-10 04:16
You should deactivate the RTH at current altitude, indoors!

It would direct land, if 3-20m away from homepoint.

You're absolutely right that I should deactivate that. Lesson learned.  
Thank you!

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Tervist
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S-e-ven Posted at 2018-8-10 04:20
And it was more as 3m away:
13.0ft        ....  Signal Lost. Aircraft returning to Home Point

No way was it 13 ft from me at when the signal was lost.  I don't even understand how the software came up with that number. But since that's the number it needed to use to determine its actions then I understand why it did what it did.
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Tervist
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S-e-ven Posted at 2018-8-10 04:31
I also notice in the log that the RTH altitude is set to 30m. Why is that messaging displaying if the aircraft is set to return to home at the current altitude?"

Because if further away as 20 meters, it would RTH on setted RTH heigh, anyway.

Our house is one story but the ceiling in the living room is vaulted, which makes it higher than average. Lots of contemporary homes in the US have this feature to make a room appear larger.
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