[TheOtherCliff]

I think that the authentic DJI GPS uses generation #6 Ublox GPS.

Most all the other brands, including clone DJI GPS use generation #8 Ublox GPS.

The older GPS version can only see USA GPS satellites.  The newer GPS version can use other countries' versions of GPS, notably Russian satellites, so the clones are better in that regard.  The clone that I bought has two firmware problems and one hardware problem though.  I wrote the DJI driver, so I did a lot of overnight testing. 

I fly (or have flown a lot) OP GPS (several versions), APM, PixHawk, DJI (authentic and clone) and they all work, even the DJI clone with the problems has only had a noticeable issue once, and I switched to Attitude mode to land it.

To switch to a different brand of GPS, you must change both the GPS type and the mag type.  Maybe that is the issue you had.

[Jhinta]

I think that the authentic DJI GPS uses generation #6 Ublox GPS.

Most all the other brands, including clone DJI GPS use generation #8 Ublox GPS.

The older GPS version can only see USA GPS satellites.  The newer GPS version can use other countries' versions of GPS, notably Russian satellites, so the clones are better in that regard.  The clone that I bought has two firmware problems and one hardware problem though.  I wrote the DJI driver, so I did a lot of overnight testing. 

I fly (or have flown a lot) OP GPS (several versions), APM, PixHawk, DJI (authentic and clone) and they all work, even the DJI clone with the problems has only had a noticeable issue once, and I switched to Attitude mode to land it.

To switch to a different brand of GPS, you must change both the GPS type and the mag type.  Maybe that is the issue you had.

is there a source? (arduino?)
the one i have clearly doesnt work , rotating gps does almost nothing (power my smoker -> sould spike where is does only +/-1) have one of a friend where you clearly can see it spiking.
i just have realy bad luck ordering.
this one i got and not working just for ref ( https://nl.aliexpress.com/item/2016-HOT-OCDAY-NEO-M8N-GPS-Compatible-for-DJI-NAZA-Lite-V1-V2-Flight-Controller-SEP/32728812578.html )

but did go for ex-i2c mag and is fully working , but 1 port missing by that ( hoping one will ad x-bus-srxl  once its released )

[TheOtherCliff]

is there a source? (arduino?)
the one i have clearly doesnt work , rotating gps does almost nothing (power my smoker -> sould spike where is does only +/-1) have one of a friend where you clearly can see it spiking.

Sorry.  I don't understand what you are asking. 

[Jhinta]

is there a source? (arduino?)
the one i have clearly doesnt work , rotating gps does almost nothing (power my smoker -> sould spike where is does only +/-1) have one of a friend where you clearly can see it spiking.

Sorry.  I don't understand what you are asking. 

arduino source so i can add gps en mag to a arduino and arduino to revo
somwthing like this https://oshpark.com/profiles/Pawelsky

[TheOtherCliff]

It's my understanding that the source for that is closed and copyrighted.  The Chinese took it anyway and that is why we have DJI GPS clones.  There may have been a hex file or other binary available at some time.  I don't know more.

Most people just by a DJI GPS.  Clones are about $28 and authentic are about $38.

You can also buy the Arduino powered adapter with code already in it.

All these can be found on eBay by searching something like:
DJI GPS

[TheOtherCliff]

Pawelsky was active on RCGROUPS too.  That is where I saw a thread on this stuff.

[hwh]

Cliff's right, the firmware was written by Pawelsky and released on rcgroups as a hex file only.  He specifically stated he didn't want it used commercially.  The Chinese ignored him, copied the idea and design of his adapter and the hex file itself, and put out the clones.  This upset him (and rightly) and he doesn't like the clone gps units.   They do run his unmodified hex file. 

Back last year when Cliff was working on adding support for these GPS into LP I contacted Pawelsky and asked if he'd consider releasing the source code and he said no.  I don't know if he's changed his mind since then.

Even if you had the source it's hard to update the firmware in the clones, most of the time the Chinese don't burn an Arduino boot loader on them so you have to use an actual Atmel programmer to update them.

The thread over there is https://www.rcgroups.com/forums/showthread.php?2290346-Naza-v1-v2-Lite-GPS-module-alternative-(using-APM-2-6-GPS-compass-combo)

[gon]

Hi!
I'm trying to use the aux mag from my Ublox M8 (https://www.amazon.es/gp/product/B01FXD4BFS/).
The GPS works pretty well, but I'm not able to read the mag through I2C.
I've followed this indications https://librepilot.atlassian.net/wiki/display/LPDOC/Aux+Mag+Setup+and+Calibration and did all the connections properly, (including the connection of the battery before usb) but when I connect the usb, the I2C symbol in the System Health is in black with the red cross saying that the I2C has timed out. The STAB is blinking from green to black with the red cross each second (I guess due to the mag missing)

The mag's wires from the I2C bus were already in the gps when I bought it, I didn't solder anything. To discard it is a problem with the unit, I tried to connect it to an Arduino through I2C and I was detecting the device and even reading the mag without any problem. So I'm pretty sure the GPS+Mag is perfectly fine.

I've also tried to connect the Arduino to the Revo through I2C to see if it detects the fc without success, so I think the problem comes from the Revo board (Using 16.09 build).

What could I try to check if the I2C is working on the Revo side? The UAVO say:

• event_log -> I2C_EVENT_BUS_ERROR
• state_log -> I2C_STATE_FSM_FAULT

I've been trying to fix this these last days without success, would love to get some ideas!

[gon]

Okay I think the problem comes from my Flexi port. I used it before for telemetry and worked fine with an arduino, so this is why I thought the port wasn't faulty. But I've tried again for telemetry and it doesn't work anymore.

Is it possible that something has broken inside this port? Is there any way to fix it or change it?

Thanks

[TheOtherCliff]

One common problem is that a pin inside the FC connector has bent over sideways.  I have very thin needle nose pliers that I have fixed this with.  First a #11 Xacto blade to get the bent pin centered a bit more and then needle nose pliers to clamp it straight again.

If that isn't it, look over it for crash damage in that area.

I had a new board come with a badly soldered connector that I had to resolder.  Maybe a weak joint broke.

Does it have power coming out?  There are functions that transmit only or receive only so as long as it isn't + or -, you might find that it is still OK for some things.

[gon]

It has power coming out, but I don't see any visible flaw.

But the HobbyKing team has returned me the money and I bought a new one! (Very happy with their aftersales service)

Thank you anyway!

[pemil]

Hi, First big Thanks for all the work everyone has put into this project.
I'm a beginner and just build my first 180quad using a revolution fc with Ublox M8N GPS and tried external HMC5883L mag with some issues. Main problem was the mag itself. Now I have got an ST LIS3MDL that I have implemented from the HMC5x code working. I though have some strange behavior that I think I have seen with the HMC too.

At startup of the system the aux mag update is very slow. If I save the mag configuration with GCS after startup it seems to change the update frequency. I'm not sure what impact it has on the quad it works in both conditions though some more orange mag errors if I haven't restarted. 

Any ideas why this happens, should I be concerned?

Thanks
Patrik

[f5soh]

Hi,
This is the normal behavior.
Since you do not use/look the Mag settings tab, there is no need to retrieve Mag data with fast updates.
Default rate is 10s and fast rate is 130ms.
This only applies to the board <> Gcs link, flight side still updating mag data at faster rates.

[pemil]

Thanks f5soh for the answer, then I don't have to chaise that anymore
Another question...

This mag is able to be sampled much faster than the HMC5883 device, would I gain or lose anything by changing the ODR to any of 155, 300, 560 or even 1000Hz, I think with the HMC5883 it is set to its max (75Hz)?

Thanks

[TheOtherCliff]

The gyro hardware limit is 2000 degrees per second, about 5.6 rev/sec so generally you don't ever (yes we have insane mode) go faster than that.

Furthermore, most fast fliers limit that to say 720 deg/sec = 2 RPS or slower (yes some may want faster).

The acrobatic only mode (no GPS navigation) that most people use does not even use the mag.  For GPS navigation, the current version of LP uses the 3D mag completely integrated into the attitude solution, but the next version of LP has a way of only using the mag for compass heading, so it is even less important in future versions.

At 720 deg/sec the mag sample rate of 75hz would wrong by about 5 degrees on average, and in the future release that can be limited to compass heading only.  I personally use more like 400 deg/sec so it is only off by about 2.5 degrees at max rotation rate.

These amount that it is wrong is only at the configured max rotation rate.  Of course it is very accurate when there is no rotation.  It would seem that it just isn't important that the mag may be off by 5 degrees from where it actually is, but only when spinning at the highest rate.