Im having issue with the mag going out by about 30-40 degrees when I power up my motors. The problem stems from the frames, I have DJI style 450 and 550 frames with integrated power boards. If I want to have my flight controller protected and between the to layers it is to close to the live pcb causing the above problem. DJI solved this problem by putting there mag inside the GPS module which sits a good height above the frame and I wish to do similar.
I have a SE 1.0 board which have the HMC5883L mag units, my first plan was to just use a external mag and uncomment the HMC5883L and add in whatever the other one was, I only have standalone HMC5883L chips (on breakout boards). So I have remove the onboard chip I'm going to run into a I2C clashes.
What I am asking is how does one go about removing an SMD IC????
Or is there a smarter way of going about this? maybe cut the +ve trace to the onboard mag and use one of my external ones.
Moving the mag
-
NikTheGreek
- Posts: 348
- Joined: Thu Dec 08, 2011 4:17 pm
- Location: Greece
- Contact:
Re: Moving the mag
Could you post some photos ?
Re: Moving the mag
Haven't done any mods yet, was seeing if there was anyone out there that had already done this or simalar. I have a cheap SE knock off that I could do this to but I still want it to work, and i want the mod done on the SE in the end anywho. If I get up the balls to take the soildering bolt I will take pics
Re: Moving the mag
I should probably explain myself slightly better. During most of a flight the throttle is in a range that causes a constant ~30degree error, in headfree and headlock modes this doesn't matter as the direction of the compass is not important as all the movements are relative.
But when using RTH or PH the heading needs to be accurate so that when the compass has a bearing the whole copter is oriented to that same bearing. If the compass bearing is off the copter ends up flying in circles trying to correct for it flying in circles.
But when using RTH or PH the heading needs to be accurate so that when the compass has a bearing the whole copter is oriented to that same bearing. If the compass bearing is off the copter ends up flying in circles trying to correct for it flying in circles.
Re: Moving the mag
Edit: I'm now using a cheap board from hobbyking that is a cruis clone, exact same sensors and orientations just a bigger form factor.
Well apart from joining a number of IC pins together everything went great. Removed the on board sensor by means of dermal then cleaned up what was left. After that is was a simple matter of using the broken out 3.3v i2c pins to hook up a duplicate sensor with some extended wires. The difference in accuracy and smoothness of the mag readings is amazing though. Once I had the new sensor wired up I checked the GUI before recalibrating it and the mag readings were really jumpy and erratic, it shows how much it needed to compensate for it being on the pcb. Defiantly a mod I would suggest looking into if you have a GPS as well. The real test will be when I get it out flying though.
I also Figured out how to hook up a bluetooth dongle for wierless tuning of settings via my phone and broke out the 5v I2C lines for the GPS setup.
L883 IC that is being removed
No more L883
HMCL883 on breakout board from sparkfun wired up
5v I2C lines broken out to a couple of pins that I isolated so I can use my GPS unit
Everything set up and good to go, just need to make a pod for the GPS and mag to go into.
Well apart from joining a number of IC pins together everything went great. Removed the on board sensor by means of dermal then cleaned up what was left. After that is was a simple matter of using the broken out 3.3v i2c pins to hook up a duplicate sensor with some extended wires. The difference in accuracy and smoothness of the mag readings is amazing though. Once I had the new sensor wired up I checked the GUI before recalibrating it and the mag readings were really jumpy and erratic, it shows how much it needed to compensate for it being on the pcb. Defiantly a mod I would suggest looking into if you have a GPS as well. The real test will be when I get it out flying though.
I also Figured out how to hook up a bluetooth dongle for wierless tuning of settings via my phone and broke out the 5v I2C lines for the GPS setup.
L883 IC that is being removed
No more L883
HMCL883 on breakout board from sparkfun wired up
5v I2C lines broken out to a couple of pins that I isolated so I can use my GPS unit
Everything set up and good to go, just need to make a pod for the GPS and mag to go into.
-
NikTheGreek
- Posts: 348
- Joined: Thu Dec 08, 2011 4:17 pm
- Location: Greece
- Contact:
Re: Moving the mag
Good job 
Re: Moving the mag
Thanx, I'm really happy with the result. The copter (Team BlackSheep Discovery) is all finished up and had a first flight tonight. The GPS/mag pod works a treat and the mag is completely unaffected by changes to the throttle now.
Re: Moving the mag
haha, good foot 
. Is your rx a frsky one? I like and will copy your rx-antennas mounting 
. Is your rx a frsky one? I like and will copy your rx-antennas mounting Re: Moving the mag
Thanx! No sadly it is only a corona Rx. There great for parkflyers and the 4ch versions are really tiny+light but are lacking in range compared to other brands. I do have Frsky gear as well but this was the only Rx I had at the time of the build that had 7 channels.
All the antenna mount is, is a 7x7mm square pine dowel cut to the width of the Rx, 2 holes drilled in at ~45degress then I just used an old antenna tube from an RC car as the tubes.
I've always found multicopters have less range then fixed wing and I put it down to how much wireing etc there was in proximity to the Rx antenna(s). This set up has got me safely to 600m, considering I get glitches in fixd wing at 700m with it I think its going pretty well.
All the antenna mount is, is a 7x7mm square pine dowel cut to the width of the Rx, 2 holes drilled in at ~45degress then I just used an old antenna tube from an RC car as the tubes.
I've always found multicopters have less range then fixed wing and I put it down to how much wireing etc there was in proximity to the Rx antenna(s). This set up has got me safely to 600m, considering I get glitches in fixd wing at 700m with it I think its going pretty well.
Re: Moving the mag
Good work. How did you bring 3.3v to the I2C connector? Mine is 5v and I don't see any regulator on the board to tap into on the Crius AIOP v2.0 board.
Re: Moving the mag
very nice job!
im going to do the same and would like some info:
1. are both mag and GPS connected to same I2C port?
2. why did you have to rewire the pins for the GPS?
3. what changes did you have to do in the software to define the external mag?
thanks.
im going to do the same and would like some info:
1. are both mag and GPS connected to same I2C port?
2. why did you have to rewire the pins for the GPS?
3. what changes did you have to do in the software to define the external mag?
thanks.
-
kpodlewski
- Posts: 1
- Joined: Sun Jan 12, 2014 9:50 pm
Re: Moving the mag
I am also have the same questions and very interested how you managed to get MultiWii to read the I2C mag rather then the on board mag. I have a Crius AIOP V2.0 and just bought/waiting on my external compass (mag) as well as a foldable stand to mount it to. I am not just realizing I have no idea how to get MultiWii to recognize that I have an external mag rather than reading the one on the board. Please assist!! Much thanks in advance!!!