Hi,
I am new to the Spark and DJI as well. Before that I was playing with a little hubsan mini drone and tried a few Parrot Bebop but had to return it to the store due to problem with the camera.

Last Sunday I was flying the drone near my friend house to take a picture of her house and some video of it.  I started the drone and it asked for calibration, so I did it, then started it, waited for home point to be recorded with good satelite coverage. It flew well for a few minutes, I took the picture and video, but then it lost connection to the phone and at the same time went straight up at great speed.  I tried to make it come back down the it was not responding to the RC command at all. I waited a bit, watching it rise to the point were I could barely see it, then tried the right stick and I saw that it was reating to it, so I tried to make it come down again and it did. Seems it reconnect to the RC. I managed to bring it back and land it safely but that was FREAKING SCARY! It did not reconnect to the phone.

The problem is, the flight log stop right before the disconnect and so it did not record the rest of it. Is there a way to get those flight data directly from the drone? the black box? will that work? I would just like to understand why it disconnected and did only the phone disconnect or the RC as well? did I lost GPS? not sure if I was in ATTI mode or not but the fact that there was no wind really helped here.

Moral of the story, I will never ever fly my Spark when there is even medium wind, and I will never ever get it out of my sight. I could absolutely not see it on the phone, since the phone was disconnected. If that drone would not have been in my sight, I would have lost it for sure. Very very scary and now I don't trust it.

So is there a way to see what hapened after the phone disconnected?

Try the instructions & software from https://datfile.net/DatCon/retrieveV3Dat.html

Try the instructions & software from https://datfile.net/DatCon/retrieveV3Dat.html

Sparkz71 Posted at 12-19 23:54
Try the instructions & software from https://datfile.net/DatCon/retrieveV3Dat.html

I had no problem retreiving the black box, I just don't know how to interpret it, how to see it, see what hapened.

If the AC was disconnected and RTH kicked in, the default RTH height is 60M I think, that is almost 200 feet.  Even if it was close to you distance wise, it would raise to that height to travel the short distance home.  That may explain it shooting straight up when the connection was lost.

Daniella3d Posted at 12-20 09:46
I had no problem retreiving the black box, I just don't know how to interpret it, how to see it, see what hapened.

My return home is set to 30 meters. I am not sure if that's what happened as it went higher (much higher than 30 meters) and after that it stopped and seem to be doing nothing at all except slowly drifting to the right, it then started to obey my RC commands.

When it disconnected it was very near me, about 15 feet high in front of me. I have maximum altitude set to the maximum legal here, 90 meters. RTH to 30 meters. I was very near my take off point when it disconnected.

Anyway, I would like to see what happened after it disconnected, that's why I want to see the black box data.

Daniella3d Posted at 12-20 14:05
My return home is set to 30 meters. I am not sure if that's what happened as it went higher (much higher than 30 meters) and after that it stopped and seem to be doing nothing at all except slowly drifting to the right, it then started to obey my RC commands.

When it disconnected it was very near me, about 15 feet high in front of me. I have maximum altitude set to the maximum legal here, 90 meters. RTH to 30 meters. I was very near my take off point when it disconnected.

The signals are within CsvView. Select the required data & create a graph. Anything from motor speed, gps signal, rc signal & much more can be displayed. If you can read a graph or a spreadsheet, your answer will be within the data. It's up to you...  share the raw data file or post a copy for others to examine as per other threads, if it's too complicated
Good luck.

Laz22 Posted at 12-20 11:40
If the AC was disconnected and RTH kicked in, the default RTH height is 60M I think, that is almost 200 feet.  Even if it was close to you distance wise, it would raise to that height to travel the short distance home.  That may explain it shooting straight up when the connection was lost.

The default Return to home height is 30 m. But, this depends on the other setting, RTH at current altitude being enabled. The distance from RTH results in various scenarios, depending on distance. 100 m, 20 m 2m - the choice is up to YOU to select the correct options within the app & read the online manual for further guidance.Obstical avoidance may also vary & turn off, depending on battery levels & flight enviroment (clouds / fog / water).
Good luck!

Sparkz71 Posted at 12-22 23:16
The signals are within CsvView. Select the required data & create a graph. Anything from motor speed, gps signal, rc signal & much more can be displayed. If you can read a graph or a spreadsheet, your answer will be within the data. It's up to you...  share the raw data file or post a copy for others to examine as per other threads, if it's too complicated
Good luck.

HI, thank you for the help. I have not flown the Spark since that incident as I am afraid to do so. I have a bunch of files, the .dat file is 500 mb, is that the one needed and  is that too large to upload?

The signals are within CsvView. Select the required data & create a graph. Anything from motor speed, gps signal, rc signal & much more can be displayed. If you can read a graph or a spreadsheet, your answer will be within the data. It's up to you...  share the raw data file or post a copy for others to examine as per other threads, if it's too complicated
Good luck.

Hi, I downloaded and installed csvView and it looks very cool. It could not load the whole thing though, as I got a message saying that there is more than one flight control entry in this file and I must extract it. It asked me if I wanted to continue with just the first flight entry and I said yes and looking at the map, it's the right flight. I can see the straight line when it moved on it's own (RTH?). CsvView also created another smaller .dat file which is 54 mb.
Here is a screen capture. and it definitely did not land where it show on the map as this would be in the house and tree...weird.

Daniella3d Posted at 12-23 07:45
Hi, I downloaded and installed csvView and it looks very cool. It could not load the whole thing though, as I got a message saying that there is more than one flight control entry in this file and I must extract it. It asked me if I wanted to continue with just the first flight entry and I said yes and looking at the map, it's the right flight. I can see the straight line when it moved on it's own (RTH?). CsvView also created another smaller .dat file which is 54 mb.
Here is a screen capture. and it definitely did not land where it show on the map as this would be in the house and tree...weird.
[view_image]

The 54 Mb .DAT is the "real" .DAT that was extracted from the .DAT created by DJI Assistant 2. Can you share the extracted .DAT. I.e the one with filename "......FLY057.DAT" ? You'll need to use a public sharing site like Dropbox or GoogleDrive

BudWalker Posted at 12-23 08:02
The 54 Mb .DAT is the "real" .DAT that was extracted from the .DAT created by DJI Assistant 2. Can you share the extracted .DAT. I.e the one with filename "......FLY057.DAT" ? You'll need to use a public sharing site like Dropbox or GoogleDrive

Hi, here is the drobox link. hope it works:

Daniella3d Posted at 12-23 07:45
Hi, I downloaded and installed csvView and it looks very cool. It could not load the whole thing though, as I got a message saying that there is more than one flight control entry in this file and I must extract it. It asked me if I wanted to continue with just the first flight entry and I said yes and looking at the map, it's the right flight. I can see the straight line when it moved on it's own (RTH?). CsvView also created another smaller .dat file which is 54 mb.
Here is a screen capture. and it definitely did not land where it show on the map as this would be in the house and tree...weird.
[view_image]

The file from DJI Assistant may contain several *.dat files. If CsvView only sees the first *.dat file, the remaining *.dat files can be extracted individually with the program 'ExtractDJI.exe".
You can find ExtractDJI.exe within the CsvView installation directory (eg C:\Program Files (x86)\CsvView).  
Load the DJI_ASSISTANT_EXPORT_FILE_*.DAT into ExtractDIJ.exe  & the individual logs will extract to FLYXXX.DAT.   

False positions may be due to poor GPS? Your logs should show the GPS quality & data recorded by Spark.   

Daniella3d Posted at 12-23 17:35
Hi, here is the drobox link. hope it works:

https://www.dropbox.com/s/307if9ooggx3jmo/DJI_ASSISTANT_EXPORT_FILE_2018-12-16_21-07-20.FLY057.DAT?dl=0

I loaded this file straight into CsvView without extracting - no problem saying more than one flight. Strange.

Anyway - the signals look interesting.
1) Weak RC & GPS in general.
2) Tripod mode?
3) RC disconnects
4) AC flys up to 30 M
5) AC enters go home mode.
6) RC reconnects
7) AC enters Autolanding

Sparkz71 Posted at 12-24 05:59
I loaded this file straight into CsvView without extracting - no problem saying more than one flight. Strange.

Anyway - the signals look interesting.

The logs & the OP's experience seem to be the same. No surprise. Why the RC lost connection I do not know.  Umm, what version of DJI Go was used & what firmware is in the AC & RC? Later versions of DJI Go 4 may cause problems. Try V 4.2.6 - it may be more reliable with signals, from my experience. Test future versions with care & keep a backup of the version that works for you!
Good Luck. Happy Flying.

Daniella3d Posted at 12-23 17:35
Hi, here is the drobox link. hope it works:

https://www.dropbox.com/s/307if9ooggx3jmo/DJI_ASSISTANT_EXPORT_FILE_2018-12-16_21-07-20.FLY057.DAT?dl=0

I looked some at your flight. The only thing I can add after Sparkz71's analysis concerns your assertion that the Spark rose higher than 30 meters when the RTH was initiated. According to the .DAT the Spark was at 4.3 meters - approximately the 15 feet you reported. When the RTH was initiated at time 255 secs the Spark rose to 30 meters at time 268 secs. Doing the math yields a 2 m/sec rate of ascent. (30m - 4m) / (268secs - 255secs) = 2 m/secs. The GPS:velD data is obtained by using the doppler effect seen on the GPS signals. It also shows a 2 m/sec ascent. Maybe the Spark just looked like it had ascended higher than the 30 meters?

BudWalker Posted at 12-24 06:31
I looked some at your flight. The only thing I can add after Sparkz71's analysis concerns your assertion that the Spark rose higher than 30 meters when the RTH was initiated. According to the .DAT the Spark was at 4.3 meters - approximately the 15 feet you reported. When the RTH was initiated at time 255 secs the Spark rose to 30 meters at time 268 secs. Doing the math yields a 2 m/sec rate of ascent. (30m - 4m) / (268secs - 255secs) = 2 m/secs. The GPS:velD data is obtained by using the doppler effect seen on the GPS signals. It also shows a 2 m/sec ascent. Maybe the Spark just looked like it had ascended higher than the 30 meters?

I agree. 30 M may look high, but in reality Spark is small. I can see it up to 120 M at dusk with the rear lights flashing. During the day, it can be harder to see & 30 M seems a long way. I still do not know why the OP's RC dropped out, apart from surrounding buildings or a slow DJI Go 4 device?

Sparkz71 Posted at 12-24 06:19
The logs & the OP's experience seem to be the same. No surprise. Why the RC lost connection I do not know.  Umm, what version of DJI Go was used & what firmware is in the AC & RC? Later versions of DJI Go 4 may cause problems. Try V 4.2.6 - it may be more reliable with signals, from my experience. Test future versions with care & keep a backup of the version that works for you!
Good Luck. Happy Flying.

Hi, thanks a lot for the analysis. Maybe it was no higher than 30 meter and I was under the impression it was higher because I never flew it that high and it's so small!

I have the latest firmware and latest version of DJI Go 4 it's version 4.3.5. Not sure how to install earlier version on my iPhone 6 because I only saw one version of it on the App Store. I did the update firmware with the Spark connected to the computer. I upgrade the battery firmware as well.

I don't know why the RC disconnected because I was very close to it, but at least now I know it initiated a RH. The strange thing is it reconnected and I could regain control of it and manual land it because it was going to auto land in a tree probably. It was right over the tree when I took back control of it.

Bur knowing that it disconnected from the RC at such close range makes me afraid to fly it now. At least it did not lose GPS to it was returning home and I could regain control, but it is still very scary. Maybe I was too close to some wifi interference and when it rose to 30 meter those interference stopped and I regained connection? Is that what happened?

I noticed I lost the connected to the phone and then the drone rise fast, so it is good to assume that I lost connected from both phone and RC at the same time?

Also how is the app has any effect on the RC to AC connection?

BTW, I was flying in tripod mode because I wanted to take good smooth video of the house while slowly rising and tilting the camera down. I wanted to take picture of it too.

The message I got from the CsvView for more than one flight is with the original black box which is 500mb, this file I uploaded was created by CsvView and it's only part of the larger file. CsvView extracted it and saved it in the same folder as the larger file.

How do you guy see so many info in CsvVier? I don't see all this when I open the file in the program. Also how to do know there was a weak satellite signal? It means I could have lost GPS and RC, so scary.

There is DJI GO 4.3.9 available, should I try it?

Daniella3d Posted at 12-24 07:05
..........
How do you guy see so many info in CsvVier? I don't see all this when I open the file in the program. Also how to do know there was a weak satellite signal? It means I could have lost GPS and RC, so scary.

How do you guy see so many info in CsvVier? I don't see all this when I open the file in the program. Also how to do know there was a weak satellite signal?
Take a look at
https://datfile.net/Doc/CsvViewManual.pdf

Thanks for all the help! it will make me a better spark pilot. I want to learn everything there is to learn to understand its behavior.

I wish everyone a Merry Christmas and Happy New Year!

Forget the CSV map. Look at the home point & final location recorded within the datcon csv file directly.
Now plug these co-ords into google earth or whatever:
The home point is    45.5235148406817, -73.5113803961494
The landing point is 45.5235873401061, -73.511394194205

Does that look closer to your actual flight?

Sparkz71 Posted at 12-24 06:47
I agree. 30 M may look high, but in reality Spark is small. I can see it up to 120 M at dusk with the rear lights flashing. During the day, it can be harder to see & 30 M seems a long way. I still do not know why the OP's RC dropped out, apart from surrounding buildings or a slow DJI Go 4 device?

"I still do not know why the OP's RC dropped out, apart from surrounding buildings or a slow DJI Go 4 device? "

Any bluetooth device with OP?
I assume on a iPhone, no OTG is common, bluetooth is still an issue!

S-e-ven Posted at 12-24 10:22
"I still do not know why the OP's RC dropped out, apart from surrounding buildings or a slow DJI Go 4 device? "

Any bluetooth device with OP?

I think I had Bluetooth turned off but I cannot swear on it, I usually turn it off. I did not have airplane mode on, I had do not disturb turned on and was connected via wifi. I did not get any phone call coming in or anything like that, nor any message from my phone except disconnecting and the Spark rising.  My friend don't even have any wifi in her house, no router, no wifi devices of any kind except her cellular phone which was inside the house. Now I bought an OTG and it seem to work so I will see next time I fly, it will be with OTG and I will make sure that everything is turned off. It's just strange that it disconnected from so close by. I can understand if I was 2 km away, but not 15 feet.


From CsvView, it also look as if the RC came close to disconnecting a few times before it did disconnect? Next time I will keep it close and in an open field to test it. That bird needs to earn my trust...

Daniella3d Posted at 12-24 12:15
I think I had Bluetooth turned off but I cannot swear on it, I usually turn it off. I did not have airplane mode on, I had do not disturb turned on and was connected via wifi. I did not get any phone call coming in or anything like that, nor any message from my phone except disconnecting and the Spark rising.  My friend don't even have any wifi in her house, no router, no wifi devices of any kind except her cellular phone which was inside the house. Now I bought an OTG and it seem to work so I will see next time I fly, it will be with OTG and I will make sure that everything is turned off. It's just strange that it disconnected from so close by. I can understand if I was 2 km away, but not 15 feet.

I hope we are getting closer to solving the RC disconnect.  What version of DJI Go 4 were you using? I'm too lazy to search the log, if recorded.  Also turn off video cache (reset may be required). whilst testing.   

I lost trust with the bird after v 4.2.6.
Good luck

Sparkz71 Posted at 12-24 15:13
I hope we are getting closer to solving the RC disconnect.  What version of DJI Go 4 were you using? I'm too lazy to search the log, if recorded.  Also turn off video cache (reset may be required). whilst testing.   

I lost trust with the bird after v 4.2.6.

Hi, I am using 4.3.5.

How about Litchi, is it any better? Just wondering, why turn off the video cache?

In case it runs with a cable:
Your bluetooth, is it on for a watch, a tracker, ....?
It is not just important, that the phones bluetooth is off, also the devices that connect (search the bands) via bluetooth have to be away from the RC
With the cable it seems to be less a problem. Perhaps b/c there is no need for the RC to go in Wifi-repeater mode!

S-e-ven Posted at 12-25 04:02
In case it runs with a cable:
Your bluetooth, is it on for a watch, a tracker, ....?
It is not just important, that the phones bluetooth is off, also the devices that connect (search the bands) via bluetooth have to be away from the RC

I only use the Bluetooth to connect to the car ''hand free'' and sometimes to my portable speakers, so no need for Bluetooth when flying the spark. I don't have any device on me that can use Bluetooth.

Are there any towers or electric polls that may cause magnetic interference near the place where you flown it?

Aishiki Posted at 12-27 18:02
Are there any towers or electric polls that may cause magnetic interference near the place where you flown it?

Hi, there is no tower. As for the electric polls, there are the regular polls that goes along the street and some wire that goes to the house, usual. I have not fly the Spark since this incident. I am waiting for proper weather and try it somewhere else.

Hi Daniella,

If you like upload your log using this: https://www.phantomhelp.com/LogViewer/Upload/
There are more log-viewers than CSVview (wich is a great program).

Like to load your data into FRAP.

cheers
JJB

JJBspark Posted at 12-28 05:53
Hi Daniella,

If you like upload your log using this: https://www.phantomhelp.com/LogViewer/Upload/

Hi, the log won't tell you much because it disconnected and nothing was recorded after that. All I see that is strange is a message at the beginning saying:  GPS Position NoMatch

What the heck does that mean?

The black box has the full flight. CSV showed a lot of things, like it came very close to disconnecting 2 times before it finally disconnected, then initiated RTH and reconnected to the RC, then I was able to control it again.  Something made it disconnect very close to me, not sure what, but it affected the RC and the phone. Good thing the AC did not go into ATTI mode because without the connection to the RC, it's total fiasco.

Your site does not want to read my .dat file, only the flight log .txt. Can it read the dat file?

Another weird thing is when analyzing the flight before, my first flight, I see the home point was recorded 36 feet away from the actual home point where I took off. So if RTH would have kicked in, my Spark would have landed in some tall maple tree, 36 feet away from it's take off point. There was good satellite too, so not sure why it was off by 36 feet??? That's a lot and it's not good.

Daniella3d Posted at 12-28 17:18
Hi, the log won't tell you much because it disconnected and nothing was recorded after that. All I see that is strange is a message at the beginning saying:  GPS Position NoMatch

What the heck does that mean?

oke, flightlog.txt tells alot more is my opinion, but if you don`t like to share, that`s ok for me

Daniella3d Posted at 12-28 17:50
Another weird thing is when analyzing the flight before, my first flight, I see the home point was recorded 36 feet away from the actual home point where I took off. So if RTH would have kicked in, my Spark would have landed in some tall maple tree, 36 feet away from it's take off point. There was good satellite too, so not sure why it was off by 36 feet??? That's a lot and it's not good.

this happens often when there is not enough satellites at take off. Once during flight there are enough homepoint is updated, far from the RC when flying away from the start point. Its all in the flightlog.txt ....

JJBspark Posted at 12-29 03:13
this happens often when there is not enough satellites at take off. Once during flight there are enough homepoint is updated, far from the RC when flying away from the start point. Its all in the flightlog.txt ....

I would not mind sharing it but I don't have any flightlog.txt, only DJIFlightRecord. is that the file you are talking about?

Daniella3d Posted at 12-29 13:31
I would not mind sharing it but I don't have any flightlog.txt, only DJIFlightRecord. is that the file you are talking about?

yes, that`s the one, stored on your mobile device.