Help "MAG" only red or orange
« on: May 12, 2017, 05:31:51 pm »
Good afternoon everyone
I need a setup to use the revolution controller with op gps, the Mag only gets red alarm, Gps is green.

Mateusz

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Re: Help "MAG" only red or orange
« Reply #1 on: May 12, 2017, 05:53:49 pm »
This is not OP GPS. Whatever Chinese call it, check supported hardware page. This GPS does not have external Magnetometer. Built-in on FC is impossible to use on some builds.

Re: Help "MAG" only red or orange
« Reply #2 on: May 12, 2017, 06:05:30 pm »
All right, how to configure the "GCS" to work with what I have, set the return to base?

Mateusz

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Re: Help "MAG" only red or orange
« Reply #3 on: May 12, 2017, 07:24:18 pm »
You can't use any navigation features as long as magnetometer is anything else than green. Either you mount your flight controller on a mast or get external magnetometer (can be GPS with mag). Also this GPS has very poor small antenna with not enough clearance as recommended in Ublox specs.

P.S please don't "I will do it anyway", it will not work as long as mag is not 100% time green. That's the only sensor that can determine heading and that GPS with that antenna won't give you any good flying experience.
« Last Edit: May 12, 2017, 07:33:57 pm by Mateusz »

Re: Help "MAG" only red or orange
« Reply #4 on: May 12, 2017, 07:56:55 pm »
I understand that the GPS has no magnetometer, but the revolution has an internal magnotometer, I can use the internal?

Jhinta

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Re: Help "MAG" only red or orange
« Reply #5 on: May 12, 2017, 08:43:20 pm »
Quote
You can't use any navigation features as long as magnetometer is anything else than green. Either you mount your flight controller on a mast or get external magnetometer (can be GPS with mag). Also this GPS has very poor small antenna with not enough clearance as recommended in Ublox specs.

so yes if you mount your fc on a pole or get a external like a gps with mag, but having a fc on pole i think you wil go for a ext-mag  8)
also there is a topic about ext-mag , read it fully

but sort answer NO !! onless you have a big drone, but you still need som basic info about how a mac works en when not.
« Last Edit: May 12, 2017, 08:50:27 pm by Jhinta »

Re: Help "MAG" only red or orange
« Reply #6 on: May 12, 2017, 10:18:39 pm »
I have a big quad (500mm anyway) that works with onboard mags, but it is not perfect, and I was careful about many things that a new hobbiest might not know:
- Twist all high power wire bundles all the way from battery to motor
- Use a PDB that does not have a bad mag field
- Mount PDB as far down as possible and FC as high up as possible
- Strap the battery on below the PDB, not in the middle of quad
- Move lipo alarm away from FC (thanks Laurent)

You should do all these things for an aux mag as well as for an onboard mag.

Jhinta

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Re: Help "MAG" only red or orange
« Reply #7 on: May 13, 2017, 12:59:18 am »
- Use a PDB that does not have a bad mag field

witch are you using?

Re: Help "MAG" only red or orange
« Reply #8 on: May 13, 2017, 01:51:57 am »
I use this style when I can get them for USD $1 or less.
http://www.ebay.com/itm/ESC-Multirotor-Power-Distribution-Battery-Board-For-Quadcopter-Multi-Axis-Model-/262917592251

I have seen designs that are much worse for mag fields.

A simple design that is entirely a sheet + on one side and entirely a sheet - on the other side with each power pair exactly soldered above/below (instead of side by side) would be perfect, but I have never seen one, and the copper plate would not be as well utilized and it would need to be a little thicker.

This is 50mm (2 inch) so it is too big for tiny quads.

Mateusz

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Re: Help "MAG" only red or orange
« Reply #9 on: May 13, 2017, 07:13:42 am »
I understand that the GPS has no magnetometer, but the revolution has an internal magnotometer, I can use the internal?

You can't use internal for flying, but internal is still needed to find the orientation of external Mag..

  • Check if there is no strong magnet, gimbal motors, buzzer close to Revo
  • Select in GCS use both Mag, then perform Mag calibration outdoors
  • Find the right AuxMag orientation angels (pitch,roll,yaw) in Mag Settings these numbers should be multiply of 90 in most cases. For example my external mag has orientation (0,180,0)
  • Check in Scopes that both Internal and External magnetometer follow the same pattern when quad is moved. In time curves should behave the same for both Mags.
  • Select in GCS to use AuxMag only once you have completed above steps

Get an external magnetometer (for example https://www.adafruit.com/product/1746) or get a GPS with built-in Magnetometer (attached photo of mine).
In my GPS I had to change connectors and bought from ebay sets of 20 cables with JST-SH 1.0 4pin (1.0 stands for 1mm pitch).

My GPS uses I2C bus to connect magnetometer, so I had to use two ports one for GPS and one for Mag. You can also buy original DJI Naza GPS, which has magnetometer integrated to deliver Mag with GPS messages, but you also need to cut and change connector. There is one option in GCS for OP GPSv9 (this is not your GPS) and it's kind of legacy option for not produced anymore OP GPSv9 which you can't buy anywhere. Maybe there are some clones, but I dont know about their quality.

One last thing. You aircraft has to fly perfect with Complementary, only then you can add complexity such as more sensors. For any navigation features to work you need all sensors with no exception working perfect, all time green with no alarms and correctly configured. Green Mag is not enough if you mount it wrong or you have orientation set wrong.

More GPS:
Also GPS must be good quality, normal GPS has 3-5m errors that it wanders around, but +-10m spikes are not good. Actually you won't be flying GPS, but GPS will be helping other more accurate sensors once you enable INS13. Your GPS you can check by right clicking on the map and selecting diagnostics to see the red path which is the RAW (not corrected by INS13 and other sensors) GPS position. When you have no buildings in testing area (they cause reflections/position spikes) position should jump +-4 meters, wander around. But if there are no obstacles and it still jumps +-10 meters, that is not good (maybe no Surface Acoustic Wave - SAW filter on cheap GPS or really bad small antenna without enough clearance as recommended in specs).

I would not recommend flying with patch antenna close to buildings but you can try helical antenna which has better reflection rejection
Here is one wiki link https://librepilot.atlassian.net/wiki/display/LPDOC/Homemade+Helix+GPS+antenna

But first fix one problem at the time, get external Mag and don't try flying with internal one.