MTK 3329 GPS Issue

[a8med]

Having trouble to change the baud rate on the gps. I have connected it to the pc using an FTDI unit. I don't want to download the ROM file using Flash tool V1.0

Tried Tera Term to se if i can get any info from the gps at all but it don't print any text at all.

I know that the gps works because when i connect it to the MW board and connect the board to GUI i can see that it is locket to 9 SAT and it blinks right on the MW board. When i set the tricopter to GPS hold it runs of far away. Magnetic declination is set!

[brewski]

As GPS is showing # Sats in WinGui & presumably MWConfig, then it is communicating correctly & baud rate must be correct. Why would you want to change it?

[a8med]

Because it is not operating correctly. Wvry time i turn on the GPS-hold the quad takes of like in this video: https://www.youtube.com/watch?v=UJrErUl ... H7&index=3


Magnetic declination is set and the compass is calibrated.

[brewski]

That is because you don't have accurate Satellite 3D lock, i.e at least 6 satellites (3 flashes of FC GPS LED) or your compass is onboard FC & being affected by magnetic fields.
Use EZ-GUI with cheap BT adapter & you can see your multi superimposed on Google Earth. This way you always know that Home is accurate & Pos Hold will not shoot off to next door & RTH will actually come back & not 50m away on busy road!
To check if compass is problem hold multi from below & connect to MW Config using USB, BT or 3DR radio. Observe compass reading whilst increasing throttle. Reading should not deviate more than 5 degrees. If it does you need to twist DC cables & move FC to a higher position & retry. If still deviates use an external Mag board which are only $5 on EBay.

[a8med]

Well i have the same problem when i have 9 satellites locket.
I am having trouble with the Bluetooth adapter too. I can se the device and pair whit it and connect but it wont transmit or revive, did try to change the TX, RX but did not help.

[brewski]

Well i have the same problem when i have 9 satellites locket.
I am having trouble with the Bluetooth adapter too. I can se the device and pair whit it and connect but it wont transmit or revive, did try to change the TX, RX but did not help.

What FC (flight controller) are you using.
From your issues & choice of GPS I'll bet one of the HK AIOP Clones.
Give up now & return it for refund & buy a genuine Crius AIOP V2. I would also return the crap MTK GPS & buy a Ublox 6M V2 (<$20 with Mag) . You can disable the onboard mag on Crius AIOP V2 by just cutting two pads (search forum) & plug in an external mag either standalone or combined with GPS. This way with combined GPS/Mag up on a mast or Mag out the front you will have no interference from high current wiring going to ESCs

[a8med]

I am using the HK Multiwii PRO: http://hobbyking.com/hobbyking/store/__ ... odule.html

After a day with product support i did get a new board but still the same problem with that one. I have tried the MTK and ublox GPS. Same issue on both.

Did make a test run where i had all the "hot" wires over 15 cm away from the gps and still the same problem (9 SAT lockt).

[brewski]

I'll assume that you have calibrated ACC & Mag. Connect to MWConfig wth Lipo attached. Have props on arm and hold quad firmly from below. Increase throttle & watch compass. It should not deviate more than 5 degrees. If it does then your onboard mag is being affected by wiring.
You can try twisting all high current cables & moving board as high as you can or best solution is removing mag chip & using ext mag board mounted on a mast. Search this forum as well as RCGroups using your board type & external mag & you will find instructions on how to do this.

[a8med]

The compass and Mag are calibrated.

ok so lets say that the mag is the cause to this problem, who do you explane that the bluetooth dont work? It is not effected by the functionalty of the mag.

[brewski]

The compass and Mag are calibrated.

ok so lets say that the mag is the cause to this problem, who do you explane that the bluetooth dont work? It is not effected by the functionalty of the mag.

BT is another issue. If you can see it & pair with it on your phone then it is transmitting. The Red LED on BTshould go solid when paired.
If EZ-GUI reports "Not Connected", "No Data" after you hit Connect then crossover the TX/RX lines. The BT modules are normally set to 115200 baud so check in Config.h that you have serial ports set to this. You can set them all to 115200 as GPS port setting will override.

[a8med]

Did some test to see if the compass change with high throttle. It did not. I had the BT on during the test and here is some pictures: https://www.dropbox.com/sh/yfmwlyf7qx13 ... yJbfa?dl=0

Moved the multiwii higher up but still the same problem. One of the motors goes full throttle when i turn gps-hold on. So i disarmed the tri and rotated it 90-degrees and tried again. The same motor went full throttle.
Meaning the same problem as before.


Note the tri was on the ground all the time so i dont know why it says altitude 27m. And i did calibrate the mag before testing.

[brewski]

The EZi-GUI altitude problem I have seen occasionally. Try disconnecting Lipo & reconnecting. The altitude should now be reset as zero, but will drift several metres as Baro warms up. There is no known fix for this.
With EZi-Gui connected check the motor graphs as you throttle up & see if the motor graphs increase fairly closely as throttle raised to hover point with props on. If so your FC is working correctly. Whilst holding firmly tilt in all directions & ensure that your tri firmly resists change. If all OK then enable Pos Hold + Horizon (no Mag). if a motor increases dramatically with Pos Hold enabled then GPS thinks position is somewhere else & it is trying to fly there. Check the multi position on Google Map in Ezi-GUI to see how accurate position is.
You should also take note of Solar activity as you can get crazy GPS performance even with 9sats if Solar activity high.

[a8med]

I did fly the tri during the summer many times, it flies well. Did also use the headfree function to comfurm that the mag works and i wored like a charm. So everything works great as long I dont use any GPS functions.

But as you can se in the pic, I do have 7 sats lockt and a home position.

[brewski]

Post your Ezi-GUI pics on the Ezi -GUI forum & Ezio should be able to help.
Are you running latest version of EZi? Solar data is not displayed in the screen shots.
Also if you are having issues in Winter are you running MW2.3 Navi b7 or latest MW2.4 beta where the Baro drift at low temp is fixed?

[a8med]

Just did some more testing and upload more pictures in the dropbox: https://www.dropbox.com/sh/yfmwlyf7qx13 ... yJbfa?dl=0

I am really confused now. First of all, if you take a look at the map picture you can see poshold point somewhere in the ocean far away from me. I tried to setting pos and home in the same position the tri is in (my backyard) but as soon i arm it automatically reset the pohold position in the ocean. Also even i have the switch programmed to activate poshold as you can see in the picture, it does activate return to home when i hit that switch (no switch is programmed for return to home). Funny thing is that it isn't trying to get to the position hold place, it is trying to get to the opposite direction. No matter how I turn the tri it is trying to get to the opposite direction of the poshold in the ocean.

[brewski]

Sounds like compass is offset 180 deg. Use a compass to check.
Is arrow on FC pointing to front of multi? If it doesn't or you can't mount it in correct way then you will have to correct it with offset 180.

[a8med]

The FC is mounted in the correct direction. But alright if i offset the compass the tri will fly to the ocean. How do i get it to place the poshold in the current position and return to home in the start position and not the freaking ocean? Could this be manipulated in the code? If so where in the code? I can upload the code to dropbox if it helps.

[brewski]

Did you try with compass? Align front of tri to north using MWConfig & check with compass that this is correct. You also need to set the Mag Dec to where you live , use online tool (link on MWConfig) to find correct setting. Of course you must calibrate compass well away from any metal or magnets.
There is nothing in code (besides Mag Dec & offsets) that can affect position accuracy.

[a8med]

Where in the code do i offset the compass ?

I just recalibrated the mag and it is pointing north on the map when the tri is pointing north. Still the problem with the poshold being in the ocean, i set the home position and poshold to the current while the tri was armd throw the BT but that did not help.

[brewski]

Where in the code do i offset the compass ?

I just recalibrated the mag and it is pointing north on the map when the tri is pointing north. Still the problem with the poshold being in the ocean, i set the home position and poshold to the current while the tri was armd throw the BT but that did not help.

Ok if tri is pointing in same direction as compass & tri rotates in all planes with same orientation in MWConfig as you are rotating it then your FC is correctly mounted & no offset required.
There must be an issue with the MTK 3329 GPS. There is a program you can download for MTK similar to UCentre for UBlox where you can test GPS and set parameters.
For <$15 you can get a Ublox 6M (or approx. $20 Ublox 6M with ext compass) that will give superior GPS performance and with module with integrated Mag superior mag performance if mounted on a mast away from magnetic interference. I am running a Ublox 6M & separate Ext Mag & get Pos Hold within 1m & RTH or Missions the same.

[a8med]

I do have a U-blox GPS, it is the same problem there. I have also tryed diffrent FC of the same kinde. I cant get theublox center or minigps to work, have an ftdi adapter.

[brewski]

I do have a U-blox GPS, it is the same problem there. I have also tryed diffrent FC of the same kinde. I cant get theublox center or minigps to work, have an ftdi adapter.

Crossover the TX & RX from GPS to FTDI. If you can't get UBlox working in UCentre you can't set baud rate. Most UBlox are set to 9600baud (or 38400 if any mention of APM) so try both of these to connect with UCentre. If you do have a UBlox that was configured for APM you will have to reset it to default & then set to 38400 to work with MW. If you still can't get UCentre to work post in Boards Shields & Sensors as well as Google "Configure UBlox for Multiwii". Some great info as well on RC Groups forum.

[wiipro]

i have another problem... when I was experimentating with sonar, i accidentally connect GPS GND to FCs 5V and vice versa. Now the small led on the GPS lights up, but it shows that GPS is disconnected (blue led is still) I try everything, but nothing happens... shit...