QC102

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Revo Mini - Which GPS?
« on: June 24, 2016, 07:07:06 am »
I have   just fitted  a Revo(lution) from Banggood - to a 450 frame.  Was following 360Painless on youTube - in which  he was about to use the $16 Oplink module (  all in a kit BG supplied)   But he seems to  have  binned it and used a better GPS module.
I have read post here and other forum, watched loads of YT vids on  GPS etc,.
I  don't have a load of spare cash for hobbies - so I need to look at best options around $100.
If  its not breaking forum rules... can I ask all you who use the  Revo / revo mini and use GPS for you user reports. 
Another reason I did not dive into the Oplink was that  some users reported difficulty setting it  up. So I suppose I should had " easy to set up" as one of my requirements.

TIA

zukenj

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Re: Revo Mini - Which GPS?
« Reply #1 on: June 24, 2016, 04:15:31 pm »
Hi QC102.

I have the NEO-7N-GPS with compass and it works great, I get normally 10 Sats lock, and it does it really fast.

I order mine from the US wherehouse.

Here is the Link:
http://us.banggood.com/Wholesale-Warehouse-NEO-7N-GPS-with-Compass-for-CC3D-Revolution-Sparky2-SP-RACING-F3-wp-Usa-1005951.html

Good luck with your choice
FS-TH9X RC
F450 Clone
Revolution FC
EMAX 2213 935 KV
HK 30A ESC UBEC running BLHeli 14.4
10x4.5 Propellers
DJI Naza clone Ublox M8N GPS

hwh

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Re: Revo Mini - Which GPS?
« Reply #2 on: June 24, 2016, 05:09:13 pm »
...the $16 Oplink module (  all in a kit BG supplied)   But he seems to  have  binned it and used a better GPS module....
An oplink is a telemetry radio, not a GPS. On a full size revo (36mm square) it's soldered to the bottom of the board.

I'm guessing you're talking about the "OP GPS" that comes with some of the Chinese packages. Smaller ones, 20mm x 25mm?  Usually pictured with a coin next to them. They're tiny lower performance GPS whose main feature is size.  The downside is the tiny antenna makes them less sensitive than the full size ones.  They also don't have an external magnetometer in them.

On a 450 size frame if you're careful with wiring you might be able to use the revo's internal mag but if you're buying a new GPS the price difference for one with an external mag in it is not much.  The one zukenj posted a link to has one.  It's what's called an I2C one and takes up a second port on the revo.  There are also ones that only take up one port, clones (or originals) of the DJI Naza GPS.  Both are a good choice.

Since you already have the small GPS you might as well try using it before buying another one.  It may work fine for you.  There is no "difficult setup" for a GPS on a revo, just plug it into a port and set that port to GPS/57600/Ubx.  The revo will configure it as it likes.

QC102

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Re: Revo Mini - Which GPS?
« Reply #3 on: June 25, 2016, 05:17:00 am »
I do not actually have the OpLink and thought it  best to ask on the forum as different people - will opt for different gizmo's and able to describe how they  sorted things.
What I am not all that smart  at doing - is sorting out USB home brew connectors and wiring. 
I will check out your suggestions and decide which way to go....

Thanks for  the replies and info. 

QC102

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Re: Revo Mini - Which GPS?
« Reply #4 on: June 25, 2016, 10:31:23 am »

zukenj

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Re: Revo Mini - Which GPS?
« Reply #5 on: June 25, 2016, 02:36:55 pm »
I don't see the conector for the mag. Be carful. Some times the offer it with no mag connector and you have to solder the cables. There is information on on the forum on how to do that, but akso some of the GPS does not come with the mag and you end up buying an external mag or another GPS.



Sent from my SM-N900P using Tapatalk
FS-TH9X RC
F450 Clone
Revolution FC
EMAX 2213 935 KV
HK 30A ESC UBEC running BLHeli 14.4
10x4.5 Propellers
DJI Naza clone Ublox M8N GPS

QC102

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Re: Revo Mini - Which GPS?
« Reply #6 on: June 26, 2016, 03:13:59 am »
I don't see the conector for the mag. Be carful. Some times the offer it with no mag connector and you have to solder the cables. There is information on on the forum on how to do that, but akso some of the GPS does not come with the mag and you end up buying an external mag or another GPS.



Sent from my SM-N900P using Tapatalk

Thanks for  the heads up on that...will do some checking - other than this...is this module "plug n play" or needing and "flashing" or whaterver before it works?

zukenj

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Re: Revo Mini - Which GPS?
« Reply #7 on: June 26, 2016, 03:18:04 am »
You just need to be running the NEXT version of GCS. To do it you will need to go to the development part of the wiki, and follow the instructions for you OS.

Sent from my SM-N900P using Tapatalk

FS-TH9X RC
F450 Clone
Revolution FC
EMAX 2213 935 KV
HK 30A ESC UBEC running BLHeli 14.4
10x4.5 Propellers
DJI Naza clone Ublox M8N GPS

QC102

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Re: Revo Mini - Which GPS?
« Reply #8 on: June 26, 2016, 07:41:19 am »
You just need to be running the NEXT version of GCS. To do it you will need to go to the development part of the wiki, and follow the instructions for you OS.

Sent from my SM-N900P using Tapatalk

Thanks for your help on this...much appreciated.

Mateusz

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Re: Revo Mini - Which GPS?
« Reply #9 on: June 26, 2016, 08:44:02 am »
If you want to use GPS with Revo, there are a few things you should know:

1. Contrary to what most people think at the beginning, GPS sensor cannot be used alone.
This is because GPS alone has a very bad huge error of 2-4m. If you intend to use GPS for navigation, it ONLY gives good position when data is combined through sensor fusion algorithm, with all (no exception) other sensors.

So again adding GPS to aircraft, won't make it fly better if it wasn't already.

2. Each sensor properly calibrated and giving good data is absolutely essential in the first place before attempting to use GPS for navigation

Before even attempting to use GPS for navigation, it is absolutely essential to have calibrated and good data from all sensors with no exception.
Each sensor measures different type of information that is minimum what you need. For example GPS does not know heading, that is only obtained from magnetometer...

3. The sensor fusion algorithm (INS31) which is basically Extended Kalman Filter, is designed to deal with noise. Although it does it to some extend, if one of your sensor feeds completly wrong data to the filter, it won't be able to handle this.
That's why all your sensors must be working properlly.

Now possibles problems you might encounter
- Internal magnetometer is too noisy, you must use external magnetometer mounted far from electronics/motors etc.. That's why it is convinient to have Magnetometer in the GPS unit, mounted on a 14-16cm not rotating mast. It is essential to calibrate Magnetometer outdoors, far from walls, and metallic objects (best done over OPLink radio).
- Baro might be noisy (some clones have problems), once baro is giving good data, you should tune Altitude PIDs such that your aircraft can maintain altitude in Complementary Filter (Basic) mode.
- You should tune your PIDs such that aircraft is responsive but not oscillating.
- You should eliminate vibrations.

Once your aircraft flys great in Complementary Filter, you can start thinking about adding GPS.

Hope that helps.
Also please read post by Cliff  - The ABC Steps of Autonomous Flight on Multicopters https://forum.librepilot.org/index.php?topic=15.msg36#msg36
It will pay off :)

QC102

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Re: Revo Mini - Which GPS?
« Reply #10 on: June 27, 2016, 07:00:26 am »
If you want to use GPS with Revo, there are a few things you should know:
Once your aircraft flys great in Complementary Filter, you can start thinking about adding GPS.
Hope that helps.
Also please read post by Cliff  - The ABC Steps of Autonomous Flight on Multicopters https://forum.librepilot.org/index.php?topic=15.msg36#msg36
It will pay off :)

Hi Mateusz
Thanks  for that information...which has saved me a lot of time and effort - and cash!   As you may have gathered - I am fairly new to quad  building projects.  While I dont  wnat GPS for navigation - ie  DJI Phantom type of sending the quad 2000 meters etc - I did  assume it would had some stability and minimise wandering around.
I guess I should  spend more time reading up and learning more.

Info and advice appreciated.

Mateusz

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Re: Revo Mini - Which GPS?
« Reply #11 on: June 27, 2016, 03:39:01 pm »
Hi  again QC102,
People make nice movies even with simple CC3D or Atom boards... some examples from mrheli :)


From first movie 4:13 is actually scary :)



« Last Edit: June 27, 2016, 03:45:55 pm by Mateusz »

QC102

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Re: Revo Mini - Which GPS?
« Reply #12 on: July 05, 2016, 07:26:44 am »
Hi  again QC102,
People make nice movies even with simple CC3D or Atom boards... some examples from mrheli :)


From first movie 4:13 is actually scary :)

Hi Again..

Sorry for a delay in my reply...had family jobs to  do...like  laying a new patio area paving!
I actually found that  video - flying in and out of your window - a  while back -  when I was searching info on the Atom.
I had it mind to build a 250 racer.... but.. the reason I logged in today was to look for information about the Atom.
When I  tried to convert it from OP to LP - something went wrong and now all I have is  the steady green light - no blue at all...so I am  guessing the boot loader is bricked.   I thought I saw a post  where they shorted some pins to wipe the  boot loader...but so far not found  it - or anything that may help.
I have stood back from adding GPS to the Revo or another 450 quad frame  which has the Naze32 10dof FC - until I learn more about adding GPS and what other  bits are needed.
The videos look great and I hope  I can ever be good enough to build and setup a quad  that I can confidently  send in and out of windows!  Just now I have  trouble getting it to stay and  20ft  by 25 foot garden space!

Thanks for taking time to reply - its appreciated.

hwh

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Re: Revo Mini - Which GPS?
« Reply #13 on: July 05, 2016, 04:04:28 pm »
...When I  tried to convert it from OP to LP - something went wrong and now all I have is  the steady green light - no blue at all...so I am  guessing the boot loader is bricked.   I thought I saw a post  where they shorted some pins to wipe the  boot loader...but so far not found  it - or anything that may help....
For bootloader recovery on cc3d/atom by shorting the SBL (Serial Boot Loader) pins the procedure at http://www.southquay3d.com/index.php?route=news/article&news_id=9 is usually used.

Other than physical size/shape the atom is just a cc3d, all information about the cc3d applies to the atom as well.

troll

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Re: Revo Mini - Which GPS?
« Reply #14 on: July 06, 2016, 03:01:57 pm »
Is it possible to use Ublox NEO-6M with Revo?
Like this:

http://www.ebay.com/itm/Ublox-NEO-6M-GPS-Module-Aircraft-Flight-Controller-For-Arduino-MWC-IMU-APM2-/311569476192?hash=item488afcea60:g:ZDwAAOSwuzRXdieK

I have idea to connect this with 4 wire cable to Flexi port (reversed TX/RX)
Should I use NEXT revision for autopilot?

Thanks.