Revo / GPS V8 Lockups PH and VR Flight modes
« on: April 22, 2016, 02:05:59 am »
I'm attempting to setup GPS for the first time on my Revo Eachine 250 FPV. I've got the INS13 as Attitude Estimation, and am trying to do position hold as Pos 2 Flight mode. All is calibrated, except Bias since I can't get past this point. I let the rig stabilize for over 15 mins to get a good signal. I'm using Oplink to monitor telem on my PC in the house. The very first time I can arm it, it only lifts on one side. No flight. It's in stabilized mode at this point (Pos 1). After disconnecting and connecting the battery I cannot arm it at all. (Still Pos 1) It gets several alarms coming and going. ATTI, MAG, TELEM, and the master alarm at times. I've tried this about 5 times now over several days with no luck at all. It flies fine, with the GPS working, (but only in Stabilized Modes) and I can log flights in GCS, I can just never get air using any kind of GPS flight modes. All kinds of alrams and such going on. Do I need to do something different in my setup? I've lowered my GPS baud rate down to 38400, UBXrate is at 5, and my Oplink baud is set at 38400 as well. It just seems to loose its mind whenever I try to use anything other than Stabilized for a flight mode. The only way I've found to recover from this lockup has been to Update and erase the device, and start all over from the start. It seems like once it gets this into it, its corrupted for good. After a cool down period (if not erased) it will fire up again, but repeat the same errors, and lack of flight. Even if I wipe all GPS modes from the Switch positions! Come on, all I'm doing is changing the Pos 2 Flight Mode to Position Hold!.
Any help would be appreciated. And my apologies if this is the wrong forum to post this, as I'm a newbe.
I'm using LibrePilot 15.09, and my boot loader is version 6 running 15.09 Firmware.


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Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #1 on: April 22, 2016, 02:25:13 am »
Please post your config file.
File > Export UAV Settings.

As a first comment, i doubt you can maintain all green alarms, especially the onboard MAG while using a mini sized Quad.
You should use a auxmag, currently supported using the next branch (or future release)

You cannot arm while a GPS flight mode is engaged.

Welcome :)

Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #2 on: April 22, 2016, 03:22:39 am »
Thanks for the quick reply.
Here is my current config (UAV Settings) "PH_Settings.UAV"
I have it set for default settings on Pos 1 when arming, and only changed to PH on Pos 2. When I bench test it, it seems to work fine. Although the Mag does turn orange briefly when throttling it. I just tried the Ext Mag settings I read about in the forum, to see if that would work, and re calibrated the sensors. All the sensors seem pretty good. I Just changed the Pos 2 to PH, and tried it again. Same results. It only lifts on one side in Pos 1 (Stabilized) when armed. I'm not going to try anything (Pos 2 PH) till I can get it to lift off in Pos 1 (Stable). If I removed the battery and reconnected it I'm pretty sure it would have not let me arm it again at all. I understand that is the GPS preventing it from arming.


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Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #3 on: April 22, 2016, 03:35:56 am »
The horizon that move a little while the INS13 is used is normal.

It uses all sensors, not only Accelerometers and Gyro like the Basic (complementary) fusion algorithm.
While running indoor, the GPS can also reports wrong position and velocity jumps and in fact horizon moving.
The Mag is taken in account for Attitude estimation so it should be green all the time.
Waiting all sensors are ok the INS13 cannot initialize.

Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #4 on: April 22, 2016, 03:46:29 am »
I was wrong, it did allow me to arm it now after a cold start. Here's some screen shots of my GCS telemetry.
Stablized (Pos 1) Armed, motors spinning at about 20% MAG Alarm. (Armed-20.png) Alarm is intermittent about 1-2 seconds.
Stablized (Pos 1) Armed, motors spinning at about 20%  NO MAG Alarm (Armed-20-Mag_ok.png)
Armed in Pos 1 and switched to Position Hold mode (Pos 2) after takeoff, motors at about 20% All Sensors reading fine, and stable. (Armed-20-PH.png)
My rig, except GPS where FPV antenna is located, and Oplink antenna on the back by battery input wire. Revo mounted where CC3d was located. (250-FPV.png)
Sorry not sure how to post them inline with this message.
Thanks again for your help.

Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #5 on: April 22, 2016, 03:59:17 am »
Sorry cross thread.
I'm running it outside with Oplink telemetry (LP running inside on my PC). 12 Sats in view and 3D fix.
Simulating test without props (of course).
But as soon as props go on, it only lifts one side. in Pos 1 Stabilized mode.
Again, It flies just fine as long as I do not use any GPS settings. Even logging GPS telemetry. I've been flying it like that all day, for a couple of weeks. But I bought the GPS for a differnet reason, not to just to see it on a map. I can not seem to get it work for flight modes.

Perhaps it's like you said, and its too small an airframe for this stuff?
Here's the upgrade package I bought for it.

Thanks again for any insight.

Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #6 on: April 22, 2016, 04:18:43 am »
Hopefully I can share this short video of the telemetry from my testing.
Bringing throttle up to about 20%, then flipping it into PH (Pos 2) mode, moving the sticks a bit, then back to Pos 1 and throttle down. Movement is from not being on stable ground. Motor torque.
You can see the only active alarm I get is the MAG blinking orange from time to time.
I was getting the Master Alarm before changing the Ext MAG settings, so I'm getting closer!

I really do appreciate the help!


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Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #7 on: April 22, 2016, 04:20:37 am »
On an eachine racer 250 with the revo mounted where the cc3d was it's unlikely you'll be able to get reliable enough onboard mag to fly gps modes.  The mag sensor is sitting 1/4" above the power distribution board.  It might work better if it was mounted with thin foam tape on top of the battery holder board I never bothered to try it and ended up using an external mag.

You just posted the kit you purchased while I was typing the above.   That gps may or may not have a mag module in it that can be used as an external mag.  Some of them do, some don't.  No one really knows why they don't put on the wires to hook it up. The banggood page says it has a compass. Take a look inside, the mag chips are about 1/10" (actually 3mm) square and usually marked either L883 or A983.  If it's there you can add wires and have an external mag if you run the next branch of the software or wait for the next release.
« Last Edit: April 22, 2016, 04:26:53 am by hwh »

Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #8 on: April 22, 2016, 04:46:36 am »
Very good, at least I know I'm trying to stuff a 450HP Chevy Corvette motor into a Chevy Chevette:D
I think it all goes back to when I put a lawnmower engine on my bicycle...but that's another story.  ;D Although I did get that to work!
I will look into the GPS in the morning.
Could you tell me when the next release it due out? And will it have any wiring diagrams for the ext MAG connections? I'd imagine they're I2C?
I'll also run the Revo on the top plate as you suggested. Is foam a solid recommendation or can I use standoff's?

Thanks again for the tips and advice.
Lots of good info here.


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Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #9 on: April 22, 2016, 05:30:55 am »
Actually, most 250 and smaller are hard to get the onboard mag working correctly.  That was the reason for the external mags.   The one you have would be I2C if the chip is inside.   There are several threads that show how to add the wires.  Even a video showing how in

You can mount it however you want, I was suggesting foam tape because I was thinking of inside the craft where there isn't much room.  My eachine 250 has the middle layer that holds the battery in place. Some don't have it.  I was thinking of trying to put the revo on it, essentially half way between the top and bottom plates.  On the top plate would be better for the mag sensor but more exposed to damage.  And you don't need to move it at all if you can get an external mag working.

Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #10 on: April 23, 2016, 10:00:53 pm »
Been working all day on the "Next" release I built, and the external MAG. No luck. It is very unstable. Sometimes the MAG is working there, and I can calibrate it, (although it is %50.00 off of the internal settings. I have tried to adjust the Pitch Roll and Yaw settings to get the bars to as close to 0 as possible, (but then as it is doing) I loose the MAG or something else goes south. I do not understand French, and maybe I'm missing something about setting up the Ext Mag in LP "Next" build?

Now I'm wondering. I have the Neo M8N as pictured below. The tutorial you have sent me to shows this board as well, and it says to solder the Ext Mag to the solder points in the Yellow Circle. I'm thinking that is the GPS signal connection, but the actual Ext Mag connection is in the photo Circled in Blue, (towards the top of the board), and I should have soldered the wires there instead.
Any help appreciated.


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Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #11 on: April 23, 2016, 10:21:01 pm »
The pads near the connector are the correct ones.   The ones at the top are the SCL/SDA for the serial EEPROM. and have more info on external (and internal) mag setup and calibration than I know.

Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #12 on: April 23, 2016, 10:27:12 pm »
Here's as close as I have got it after many hours of poking at it, with the wires next to the connector on the M8N board. I'm getting more convinced that I should solder the Ext Mag wires on the other pads at the upper portion of the M8N board. (Pictured in the blue circle in the photo above.)
Here are my settings as well.
I've got 12 - 14 Sats in view, I2C is green, but Atti | Stab and Mag are red.


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Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #13 on: April 23, 2016, 10:31:26 pm »
Redo the wiring, keep short as possible and twist wires.
If they sell the same model sometimes with I2C wires and sometimes without maybe some units do not pass the quality check.

although it is %50.00 off of the internal settings.
I don't understand... both Mags should be running with Green alarms.

You cannot adjust (and use !!) the auxmag orientation bars with both mag alarms....
See the little help text above the 3 bargraphs.
This means there is a strong disturb magnetic source, like a buzzer or other magnet around....

Re: Revo / GPS V8 Lockups PH and VR Flight modes
« Reply #14 on: April 23, 2016, 10:43:36 pm »
Thanks for the replies! I'm going to digest the second link you have sent me tonight, and work the steps there. I have already viewed the 1st link you have sent me a few times while trying to get it working without the Ext mag modification. I'm using two jumper wires for an Arduino since I did not have any other wire laying around. So they are not twisted, in fact they are stuck together, and running along externally on the other wire coming from the GPS to the Flexi port. If all else fails I will be trying to move the Revo to the top plate as was suggested in previous threads. It was suggested that I wouldn't have to move the Revo if I could get the Ext Mag to work. I really wanted this to work, and thought that would be more work and aggravation than this fix.

Nice job on the "Next" build by they way. I was nervous there for a while as I could not get my Telem PFD screen to come up, and had no errors on this build. (I've had to build it twice). It did "Pop" into play a little while ago. I deleted all the screens and rebuilt them from my other install as a template. One more bummer is my field PC is 32 bit, and my main PC is 64. The field PC is not powerful enough to build the Next, so I'm kind of stuck just using the main PC now. Not so good for the field, although if it records telemetry with the 15.09 version I should be ok. I did notice is shows that.

Thanks again.