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Hobbyking MultiWii PRO with MTK GPS

lobstermash

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#1
Hi guys,

Flight controllers don't seem to be a popular subject on Flitetest. But I'm the kind of person that likes to dig deeper into subjects until I get bored or conclude I've hit a dead end.

Since getting into FPV a couple of months ago, I've been troubleshooting my kit to make it safer and perform better. I had some video performance issues in some areas, which I fixed by making some cp antennas. I then ran out of battery on my first flight with the new antennas, because I forgot to set a timer and didn't have an OSD, so I got a G-OSD II and flashed it with CL-OSD. I then flew behind myself and lost control signal, which prompted me to get a FrSky system to beep at me when the signal was low. I was also restricted to the length of my cable, so I got a 5.8 100mW vtx to relay the video feed to my goggles. My current issue is interference between my rx and vtx, which I've moved further apart but haven't tested my range yet.

In any case, something that still plays on my mind is what happens when I ignore the beeping on my tx and suddenly lose control. I didn't want to get a whole new OSD, like the NOVA, purely for the RTH feature, given how happy I am with the G-OSD. So I started looking into flight controllers. I considered APM2.5, which looks pretty amazing, but I came across the Crius AIO Pro which was 1/4 of the price, though it was missing a GPS. Hobbyking suddenly started bringing out new boards, and when the MultiWii PRO with MTK GPS came up, I pulled the trigger.

Before I bought it, I checked the sensor list, which were identical to the Crius AIO sensor board (not the AIO Pro) - ITG3205 (works with the ITG3200 coding), BMA180, HMC5883 and BMP085. Also the GPS is a great unit and supported in APNG firmware. Not knowing anything about programming, I thought it'd be pretty simple for someone to adjust the scripts for MPNG/APNG to use this board, and I'd just copy them. Wrong.

So, I thought I'd have a fiddle and see what I could come up with. Unlike the Turnigy 9x and G-OSD, the powerful Atmega2560 requires much more than a quick eeprom and/or hex flash. I used eepee and eXtremeBurner respectively for the 9x and G-OSD, without modifying the .hex and .eep files. For the MultiWii PRO, I've been playing with Arduino 1.01. This program allows you to adjust parameters and active sensors etc, as long as they are defined in the coding. To check whether the settings are correct, I've been using APM Planner for APNG and Wingui for MultiWii

The setup for MultiWii 2.1 on the MultiWii PRO board is really simple - the sensors are able to be selected individually, rather than picking a particular board's set like in APNG. I could get RTH function using MultiWii, however I've become more and more interested in waypoint navigation - RTH kicking in on failsafe pushes the control system to its boundaries, but waypoint nav makes the flight battery the only restriction on range!

Anyhow, I started this thread to hopefully kick off some meaningful brainstorming on how to get the MultiWii PRO working with APM Planner. At this stage, using ArduplaneNG 2.4, I can get the GPS and baro to work, but not the other sensors, just by selecting the BlackVortex board and specifying the mtk GPS. However APM Planner won't connect to the board. With ArduplaneNG 2x R5 I can get the magnetometer working, but not the other sensors, no matter which boards/GPS I select. I haven't started mixing and matching cpp or h files yet, but hoping someone gives me a steer in case I make the solution (if it works) more complex than the problem.
 

lobstermash

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#3
OK, I finally have this board sorted for ArduPlaneNG.

The zip file should attach here: View attachment ArduPlaneNG for HK MultiWii Pro.zip

I did write a live article (I was updating as I went along) but the articles part of FT is broken. I can't add pics, there are constant errors on the site... If people want the information they can come here. Heck, it took me around 20 hours of fiddling around trying to get it to work...

For those that didn't catch the updates on the article, although the sketch in the zip file get it to work, I had an issue at the plane end of the hardware - I'm going to try and play with the refresh rate for the servos, as they're the stock, cheap analogue ones that came with the Bixler. Or I'll just get some nice little digitals to replace them.
 
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lobstermash

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#4
A bit of an update, I've got things set up OK on the Bixler, and control inputs etc are fine in manual mode and stabilise mode. However in stabilise mode, the corrections by the board in response to tilting it cause twitching in the elevator and aileron servos. I've got a couple of ideas on what's causing this, but if anyone's had a similar issue with another fc I'd love to hear what you did. There's very little info on possible solutions, and there are no verified fixes.
 

lobstermash

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#5
At this stage I'm going to declare victory. I re-flashed the firmware, erased the eeprom and loaded the Bixler parameters for APM. I must have had conflicting parameters and a clean bill fixed the twitching issue.

I have now successfully test flown the Bixler in manual, stabilise and RTH modes. In the process of trying to glue a little bit of glue to the baro, I accidentally might have got some ca in it... To get around this I set ALT_MIX to 0 - gps only. I'm not sure if the baro is stuffed and I wasn't willing to test it this time. Now that I know the board works I can test it without worry.

The RTH takes a few seconds to kick in, giving you a slight nervous moment, before it flies around in circles and the occasional figure 8s. I put the tx down and took some video with my phone, but the res is so bad you can't really see the plane. I had to call an end to the day, as at 39 degrees C the motor melted half the hot glue holding the mount in on the second flight, and I lost the tips of my prop on the Spakfilla on the boom. Damned hot days...

Oh, also tested failsafe flight. Turned the tx off, and RTH kicked in. It came back toward me and started circling, so I turned on the tx and waited to take control back. However the plane did nothing. I turned the tx off again, and RTH kicked in again. I tried taking control back again and had horrible visions of having to turn the tx back on at the right vector to come down near me. However when I looked at the tx, I noticed that the 'throttle not idle' alarm was on. I tapped the throttle and the plane kicked back in as it should. Phew!
 
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lobstermash

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#6
For all the heartache I've had with this board, and the successes, I've managed to kill it after removing the foam from the baro. I wanted to try and clean it up, and now the whole fc won't initialise and arm because the baro is no longer working at all.

I've ordered a Crius AIOP...
 

colorex

Rotor Riot!
Mentor
#7
For all the heartache I've had with this board, and the successes, I've managed to kill it after removing the foam from the baro. I wanted to try and clean it up, and now the whole fc won't initialise and arm because the baro is no longer working at all.

I've ordered a Crius AIOP...
Wut??? *facepalm*
 

lobstermash

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#8
Yup, 20-30 hours of fiddling in Arduino and Mission Planner getting it all going, and I've ruined the board in an instant with a tiny drop of glue :( If I had some microsoldering equipment I guess I could replace the baro (they're about $2 on Ebay)... But I don't so I won't.
 

Tritium

Amateur Extra Class K5TWM
#9
Yup, 20-30 hours of fiddling in Arduino and Mission Planner getting it all going, and I've ruined the board in an instant with a tiny drop of glue :( If I had some microsoldering equipment I guess I could replace the baro (they're about $2 on Ebay)... But I don't so I won't.
I have a hot air rework station :D.

Thurmond
 

lobstermash

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#12
I know. Hence the AIOP order...

Shame HK doesn't have replacement boards without the GPS. Because these are all old-ish sensors, this board will get cheaper and cheaper to produce, and really it does a good job. This could become the staple budget fc...
 
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#13
only saw this thread today !! very good progress Lobsterfriend !!

im fiddling with the options to add RTH on my new QUAD;

my options are

NAZA 400,00 Dollars;

AIO PRO 100,00 Dollars;

If you can make it work nicely i might get the Multiwii AIO PRO and the GPS for testing .....

what GPS are you using .. HK advertise they will release a 10hz soon ... where can we find those ??

Does the 5hz works good enough ??
 
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lobstermash

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#14
When they come in stock, the MultiWii PRO is $62 and includes a Mediatek (5Hz) GPS. I really rate it as a flight controller, and the GPS is very fast to lock on and pretty darn accurate. There's also good support for this board now for both MultiWii and MegaPirate and RCG.

The GPS HK advertised (although it's still only 5Hz) as coming out soon is already out - it's the UBLOX GPS that is commonly packaged with the AIOP, and at $20 it's a steal. I haven't ordered one, as I plan to use the Mediatek GPS with my AIOP.

By the way, be warned on the current Hobbyking AIOP board - the 5V regulator is not connected to ground, so essentially you either have to connect it yourself or power both sides of the board seperately. Instead of pulling it from sale and getting the defect addressed, HK have reduced the price, but don't have a warning on the product listing that it's faulty! Aside from this fairly big oversight, the rest of the board appears to work OK according to the people who have one.
 
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#15
that type of problem that made me still weight where should i invest .... i know the solution is a easy fix with a soldering iron ... but still ...

i have been seeing my friend flying his NAZA + GPS combo and its rock solid !!

I didnt made up my mind yet :p