Sunday, April 22, 2012

Quadrocopter Build - Part 9 - Education

To start, I will provide an update on my quardcopter. My X525 quadrocopter is still grounded, but I have propellers now. My issue is battery. I borrowed two different batteries from someone. It showed me that my quad was somehow draining batteries very very very fast. I have a video demonstrating that here:

Secondly, I have four purchased carbon fiber tubes (12mm x 10mm x 500mm) and a carbon fiber sheet (1mm thick) to build my own quad frame. I am waiting on more parts to put that together. I have to design and somehow cut (maybe get someone with a CNC to help?) out the frame pltes after i design them. Should be fun.


Now for the promised education.
I want to talk about something that is not clearly explained with many multicopter flight controllers/'boards'; and that is Gyroscopes vs Accelerometers

As far as I know, every board has Gyroscopes. Slightly more expensive boards use gyroscopes and Accelerometers. More expensive than that and you start to add barometer, then magnetometer, then GPS. Each of these sensors add another degree of stability or control.

Lets clarify what a gyroscope does. A gyroscope can sense rotation. That's it. They can tell that orientation of an object. One gyroscope can measure one angle for one axis. Some flight controllers use three gyroscopes to measure all three axis. There are also 3 axis gyroscopes. It does the same thing as three different gyroscopes, but generally takes up less space on the board.

Accelerometers measure linear motion (including gravity). Generally I have only seen 3 axis accelerometers used. This is likely also due to the space savings of having one over three different ones. An accelerometer can detect that affect of the wind causing something that is flying to 'drift'.

The KK multicopter flight conttroller I have been using have three different gyroscopes. It has no accelerometers. This makes flying require a lot more user action to keep it stable in wind or the air coming back from a propeller pushing air when close to the ground.

I have been looking at other flight controller boards. I think that my next board will be something that I will be able to fly with less effort by my. I would also like to have it control/stabilize a camera tilt/pan mount. I am looking for a board with:
Gyroscopes
Accelerometers
Barometer
Magnetometer
GPS
Camera stabilization

The one I am really considering is the ArduPilotMega 2.0. However the price is a little high. But with an all-in-one solution I am not sure that I have many other options. I have not seen much about camera stabilization with APM2.0, but it appears to be possible based on their site.

Let me know if you have another board idea for me with these features. I have been shying away from MultiWii and MK due to the number of add-on boards required in order to get all the features I want. I also have not considered DJI or xAircraft boards due to their prices.I can get an APM2.0 shipped to me from CanadaDrones.com for $310.

Feel free to ask me any questions, give me your opinions or just say hi!.
Bye now.

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