Quadcopter Parts

[BenKenobi]

Yes many do just jump in, and learn the hard way, it's a valid way of learning but can be somewhat expensive and in some cases dangerous.

As for the 6 axis bit I agreee but that just seems to be how they get named in countless forums and before you know it the world repeats it, but you're correct the terminology is inappropriate but most know what it means in the RC circles. The true term would be 6 axis inertial motion sensor.

There is another version used a lot too and that's a 9 axis, this adds a 3 axis magnetometer into the device, the 9 axis can be combined to make highly accurate decisions about where the device is and what it is doing using a mathematical process called sensor fusion - but this is pretty complex.

Almost everyone uses the latter but doesn't even realise it - they're in most smart phones and tablets. These are complex beasts, they don't work out of the box - in fact nor do the 6 axis - they have to be taught about the world that they are in - you can mount them in any orientation as long as you tell them about it - but if you don't do this you won't be flying level. Even slight errors in 'level' would see the multirotor drifting.

[FreddyVictor]

As for the 6 axis bit I agreee but that just seems to be how they get named in countless forums and before you know it the world repeats it, but you're correct the terminology is inappropriate but most know what it means in the RC circles. The true term would be 6 axis inertial motion sensor.

Yea, I was looking at the other persons problem with his propel quad on this forum & noticed the box claimed '6-axis gyro' to which I figuratively sighed   

There is another version used a lot too and that's a 9 axis, this adds a 3 axis magnetometer into the device, the 9 axis can be combined to make highly accurate decisions about where the device is and what it is doing using a mathematical process called sensor fusion - but this is pretty complex.

Almost everyone uses the latter but doesn't even realise it - they're in most smart phones and tablets. These are complex beasts, they don't work out of the box - in fact nor do the 6 axis - they have to be taught about the world that they are in - you can mount them in any orientation as long as you tell them about it - but if you don't do this you won't be flying level. Even slight errors in 'level' would see the multirotor drifting.

Currently been messing around with an ST LSM9DS1 9-axis sensor, but not for drones

For sensor calibration, the real pain is the magnetometer, they need calibrating to remove hard iron offsets and then the data must be tilt-compensated (for use in phones where it's not level)
I'm quite curious as to how they get them to work with little or no calibration - anyone ever calibrated their phone ?

I gave up writing my own code for drones as the maths was too complex, also, there was other freely available code which easily outperformed most other available softwares

@OP, just buy a cheap drone to see if you like it or not, you'll save a heap of money !

[Novgorod]

but he could have the satisfaction of building the DJI from a kit of parts.

Then he could go straight for one of the countless mini quad kits and it should be a lot cheaper. DJI stuff are luxury toys, which are great if you're into drone photography rather than actual flying...

The problem with the toys is that they are exactly that, they don't fly well (mostly)

Definitely true - you need to find the right one, but when you find it, you'll save yourself a lot of money and pain. I recommend beginners to get a Syma X11 or X13 (or clones), which have large (and geared) props for their size making them remarkably stable. They're neither fast nor powerful but very precise to control and easy to hands-off hover. Once you've learned how to fly circles, funnels and figure-8s without crashing, you can progress to something more serious, but until then you do absolutely nothing wrong with (the right!) toy-grade quads.

gyros have 3-axis, accelerometers have 3-axis, doesn't make it a 6-axis 'gyro'

I did't come up with the nomenclature and I know it's technically wrong but that's how most brands lable these sensors

[Rerouter]

the gyro is the only superfluous bit of information, it is a 6 or a 9 axis, 3 rotational axis's, 3 translating axis's, and 3 orientation axis's, technically GPS would be an additional 3 spacial axis's, which do not correlate to the translating axis's until a translation / rotation of the matrix is performed, then you have other sensors which are derived but not the same as an axis like optical flow sensors that measure air speed,

I would replace the "gyro" with IMU, or INU, or even sensor, but i suppose at the end of the day it conveys the same message.