Please select Into the mobile phone version | Continue to access the computer ver.
DJI S900 Owners Thread - Mini Build Log
7121 24 2014-9-19
Uploading and Loding Picture ...(0/1)
o(^-^)o
Blade_Strike
Super Moderator
Flight distance : 872694 ft
  • >>>
United States
Offline

A2
Lightbridge
iOSD MarkII
GH4 HD Gimbal
TroyBuiltModels.com 15000mah
AGA 20000mah

There was no manual available during this build. I just did it in the steps that made sense to me;) So if the manual is released and I missed something or did something out of order this is why. The quality of the s900 is about the same as the s1000 with some aluminum replaced with some kind of hard polymer. Just like the s1000 there is very little to complete. The main frame is 90% built, I went through each screw to double check for thread lock and everything was good.





Motor control connection is the same as the s1000 as well. Very clean design and very few wires. You sill use all 8 wires of the wires harness but only 6 are active. At this point you should connect the landing gear 3pin servo wire to the a2 and LG control board as well.


The top plate is a complete new design. With only 6 screws you can remove it and have access to the power distro board and access to all other components. This is a really nice feature and makes maintenance and wire routing really easy.



With only four screws the top cover of the power distor board is removed


After removing the top plate and power distro cover I connected the motor control wire harness to the a2. First plug I used starts out with a set of black wires with the lasr one being yellow, this is motors 1-4. 4 being the yellow colored wire. Next is the black set with brown going to motor 8 pin. Once again only 2 wires of the last four wires are used.



I installed the PMU on the left side and the iOSD MarkII on the right.



Next I installed the landing gear. You want to make sure you loosen both screws on the main tube so the landing strut goes in easily and does not get scared. The main tube is the same size of the s1000 so the Lightbridge antenna paddles holders will fit.




Landing gear tubes attach to the retract mounts via clamp with one screw. The landing gear tube and mount is keyed so please take note. Once secure please attach spring to the landing gear. This is easily done with a pair of needle nose pillars.



The motors are the DJI 4114 Pro's, these motors and esc's have preformed flawless on my s1000. The new motor mounts and arm mounts are some kind of polymer. When I first saw them I was a little concerned on the arm mount. But after locking each arm.. It does feel more secure than the s1000's aluminum. I guess only time will tell to see if this is a better solution than the aluminum. The motors have a new connection method as well.
  



The arms are secured by the same red clips that the s1000 uses. If you look closely you will notice the rubber plug that is inserted into the arm. This keep the complete locking system very tight and secure.



Once the arms are connected you can connect the motor power wires and esc control wire for each arm. There is 3 positive post and 3 negative. You want to double up on each one. Leave these loose for now. You will need to be able to position the power wires under the power cover. Once the cover is on you can lock everything down. Be very careful while you install the top cover of the power board. It's very easy to pinch a wire if you are not paying attention. Just take your time and it's very simple.





Once the top cover is on you will be able to clean up the wiring and put the top plate back on.


Only thing left to do is install the GPS puck and program the A2. For the first few test flight I am using the internal rx. Once I get a few flights on her I will install the Lightbridge and GH4 gimbal.





**Update 8/9/14**
Short video of 2nd test flight


Update **8/10/14**


Update **8/24/14**

2014-9-19
Use props
quadslo
lvl.3

Slovenia
Offline

What is you total weight and throttle % at hover in manual?
2014-9-22
Use props
Blade_Strike
Super Moderator
Flight distance : 872694 ft
  • >>>
United States
Offline

fully loaded with gh4 and 16000.. Just under 17lb.

I hover in manual @ 60%
2014-9-22
Use props
Dronelink
lvl.1
France
Offline

Hello,

Wich radio do you use ?

Thx
2014-9-23
Use props
quadslo
lvl.3

Slovenia
Offline

Thank you for the info.
I read that if you stay under 60% hover with hexa and you have a motor fail, copter won't start spinning to stay in the air.
2014-9-23
Use props
gadgetexplorer
lvl.1
Flight distance : 78304 ft
  • >>>
Uganda
Offline

Make sure to setup your engine shutoff to intelligent and not to immediate. I had a 6 motor/shutoff fail when I was new to this hobby on my s800 with WKM but saved the bird by CSC and restarting the 6 motors. I was lucky but I learned a lesson that could have cost me a lot, maybe total loss. I was at 300 meters altitude.
2014-9-23
Use props
Blade_Strike
Super Moderator
Flight distance : 872694 ft
  • >>>
United States
Offline

60 to 70% is a good rule of thumb.
2014-9-24
Use props
uhayat
lvl.3

Pakistan
Offline

Blade_Strike Posted at 2014-9-25 01:07
60 to 70% is a good rule of thumb.


Thanks a lot for the very detailed log, you and Fabien are my new heroes!
Just a question which might sound rather silly...
Could you please explain what you mean when you say that you hover at 60% and that 60-70 percent is a good rule of thumb?
Is this the percentage of battery you use?
Will be starting my build in 2-3 days so no flight experience yet
Thanks
2014-11-15
Use props
Blade_Strike
Super Moderator
Flight distance : 872694 ft
  • >>>
United States
Offline

When in manual mode. This mode allows you to see where the craft will actually hover at since there is no barometer active.
2014-11-19
Use props
chrisgeigerphot
lvl.4
Flight distance : 5341447 ft
  • >>>
United States
Offline

A really heavy aircraft takes more power to hover. If in manual it takes a high throttle setting to hover than you can tell it is over loaded. If it take very little throttle to hover in manual than it is under loaded.
2014-11-21
Use props
uhayat
lvl.3

Pakistan
Offline

Got it, thanks.
2014-12-9
Use props
Dboy
lvl.4

China
Offline

WoW, amazing photos
2014-12-10
Use props
rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
Offline

I look at your placement. I dont have the IOSD I use the LB for that. But I want to place the Ground Station and are thinking where to place it. Above the LB I guess would not bee good as the antennas are close and both are 2.4G. Then if I place it in the rear the cable don`t reach the HUB. Also some say you should not place a transmitter close to the IMU?`

Then Im left with on the A2 Receiver side up front. As I guess the antennas are not in use on the A2 when I use LB?

I made this chart fast so its not the best :-D Green is what I have today. If not describes as "bellow top plate" they are on the bottom plate or the front and rear positions.  Blue is where I think it will be good.

Any suggestions/experience?

S900 A2 placements

S900 A2 placements
2014-12-14
Use props
Blade_Strike
Super Moderator
Flight distance : 872694 ft
  • >>>
United States
Offline

I strongly suggest that you do not use LB and the 2.4Ghz GS. These are not compatible, you would need the 900mhz version and that does require a PC.
2014-12-15
Use props
rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
Offline

Thank you. Good to know!!! Glad I never mounted it!
2014-12-20
Use props
rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
Offline

Did the test flight today after the new arm had come.
Its been snowing and windy.

The Zenmuse has not got back from DJI so I flew bearfoot :-)

It still after reinstalling A2 software, calibrating and adjusting. It flew and was nice in the air hovering. Also flying Forward and reverse + roll both ways is great. But when using the Yaw its still feel really unstable. Im using a light battery so the rig is light.

When I raise the landing gear it gets really jumpy. It really looks like it think its something bellow like the Zenmuse that will counter-weight and it looks like the landing gear does "some" of this job and that it by this get worse when its up.

What do you think @blade_strike?
2014-12-26
Use props
rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
Offline

PS: On the Led light it made one blue "blink", then 3 short blue "blinks".
I was in GPS mode and had "home lock" before I took off.
2014-12-26
Use props
Blade_Strike
Super Moderator
Flight distance : 872694 ft
  • >>>
United States
Offline

rubenmail@gmail Posted at 2014-12-26 21:56
Did the test flight today after the new arm had come.
Its been snowing and windy.

What gains ?
2014-12-27
Use props
Blade_Strike
Super Moderator
Flight distance : 872694 ft
  • >>>
United States
Offline

rubenmail@gmail Posted at 2014-12-26 22:08
PS: On the Led light it made one blue "blink", then 3 short blue "blinks".
I was in GPS mode and had ...

This is normal.. This 8m within home point.
2014-12-27
Use props
rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
Offline

I use now the recomended Gain Settings. As it feels a bit jumpy what settings would you recomend without the Zenmuse.
My battery Weight: 1175g.

I was thinking to attach one more battery but it will still be "top heavy"?
Its now -12c outside but looks like its set for about -3 and no wind tomorrow so might try then if you can recomend some settings. I will also film and strap on a go pro so you get more info.

Sorry to bother you during christmas Ken!!

Gain

Gain
2014-12-27
Use props
Blade_Strike
Super Moderator
Flight distance : 872694 ft
  • >>>
United States
Offline

Try 145 on basic and 135 on atti.
Vertical I run 150 and 140 on yaw.

This should get you in a nice mild range and you can tune from there.
2014-12-27
Use props
rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
Offline

Thank you again. Hitting the sack now and then up in the morning to check it out :-)

PS: Would you sugest attatching another battery or as its so high up it will have no effect?
2014-12-27
Use props
rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
Offline

A small update.

As im at the Arctic Circle in Norway and its dark at 15:00 CET I made my way outside to make a small test.
I had the extra battery strapped on and made sure it was all well balanced. I was sure I had made the adjustments you sugested over the Iphone assistant. But when I now checked they had not been saved. I sometimes experience it disconnect and found others that have the same trouble and it seems to been only thoose who have LB installed.

Anyway. I made a calibration again just in case even this test was on the same place as last.
I checked that all responed while it was on the ground and it looked great.

I then took of only about 3-4 meters just to be sure in case so if it crashed or other I could save it.
It went fine straight up. As soon as I let go of the stick. It started to wobble MORE then without the extra battery/weight.
It was really unstable so I more guided it down then simply landed it and It was not more in the air then max 2 min. I saved it and landed  soft and ok.

It still looks like its "top heavy". Dont have another name for it   It was so "jumpy" I did not really have time to see if it was any special direction it was worst on like last. It will be rain for a week now but it changes fast.

Its scary not knowing but I guess it might be one step forward that it got worse when I put on more weight "high" up?

2014-12-28
Use props
rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
Offline

Blade_Strike Posted at 2014-12-28 05:42
Try 145 on basic and 135 on atti.
Vertical I run 150 and 140 on yaw.

Hi dear friend.

Still no Zenmuse but hope every day now :-)
Today or should I say tonight the weather stopped for a while as its said "silent before the storm" as its raging outside now.

For some reason the PC I have had to use during Christmas (Still not home before end of Week) want connect to the A2 and the Iphone assistant want let me adjust the gain settings.

So its still the same settings as before and as posted so sadly I have not been able to implement your suggestions.  But today in the light from my car and a Led lamp on my head + some lights from the farm buildings I was able to record a video. Sadly this is (Even as its said we are the richest country on earth) there is only Wimax and less the 3D speed on upload so had to cut it short and still it have taken 3.5 hours to upload :-(



<iframe width="420" height="315" src="//www.youtube.com/embed/pcP-wYByGJ4" frameborder="0" allowfullscreen></iframe>

Let me Explain.
00:13-00:35
1. I fire up the Futaba by inserting the training cable and turn on the Lightbridge. As I have no camera on it I attach no Iphone/screen.

00:35-01:00
2. I place the Radio on the ground and make sure its balanced before I connect the battery (Removed the extra one mentioned in the last post where it was even more unstable) and only have the one I have been using all along that has a weight of  1175g. Its placed so its balanced.

Not seen in the video
3. I wait for GPS lock. Then I make some testing to see if the sticks are "working" like Yaw, forward,backward + +.

4. The S900 is in the Air. Take of was perfect and it stand perfectly still in the air.

5. Now I Roll. I make it steady and are light on the stick. Then when I let go I get the movement where you see it has trouble balancing (I think) I make some more smaller Roll movements and as you see it wobble a lot (Again my opinion)

6. Then I try forward and Yaw with much more confidence and as you see there is not even close to the  unstable movements as with Roll.  

1:55
7: here I lift the landing gear and its has almost none effect on the general movement but as you see again on the Roll it now even take longer before it "settle down".

8. Then I raise and lower the gear again and as you see its steady as a rock.

9. Last I do one more Roll before I land it and it landed perfect

QUESTION
Will the gain adjustments you suggest fix this and do you think this is a gain value  problem?
Again I must say the rig is 100% well balanced and I have calibrated it several times at the location where this film was made. Might it be the 220 is just to much when its so light?

If this might not be the trouble what do you think it might be and can it be anything else?
Also as said before I have put more weight under it by placing another of the same battery and making sure it was balanced and then the Roll was even more and really unstable. I never tested the S900 without the Zenmuse when I got it so I dont know how it reacted without it.

As you know this is really wearing on me now. The real fear is that I get back the Zenmuse and it crashes to the ground and break it. Then I want wait until the cancer one day killl me I find a good rope and a tree close by.

Hope to hear from you mate. Also if you know any DJI representatives (Cant think of anyone better then you anyway) but they might also have a look at it you think?
2015-1-5
Use props
TravisSRT
Second Officer
Flight distance : 5568658 ft
  • >>>
United States
Offline

Blade_Strike Posted at 2014-12-28 05:42
Try 145 on basic and 135 on atti.
Vertical I run 150 and 140 on yaw.

Blade_Strike, I am having a unique problem with my S900 and was hoping for your input.  I am getting a J-Hook on full forward and full rear movement.   I am at mid throttle on left stick (hover position) and just pushing right stick for full forward and she goes and then spins to right doing 180 and stopping.  If I stay on full forward she will correct herself and then start going forward again after a few seconds but now facing opposite direction of where we started.  Here is a short video from ground and one from the GH4.  Any help would be greatly appreciated!!  Also, it doesn't usually do this in first few minutes of flight but always does it after being in the air for a few minutes.

I'm using S900, A2, GH4 with Futaba 14SG. All firmware is updated. My S900 was purchased as a completed build from JR Drones (Former Drone Dudes pilot).

First video is from ground, second from GH4

2015-4-20
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules