Detect Down, using arduino?
The desired result is a pretty simple one in this case. I am curious how you can tell where "down" is, using electronics. I'm sure It could be done by initializing gyroscopes in an initial, level position, but my friend has as small quad copter, that can take off at an angle, and be turned on at an angle, and still level itself perfectly. It doesn't have to have an initial reference to find what down is. The other option is to use accelerators, but if you are making a device to control a rocket or multirotor it is unlikely to impossible that you will be able to isolate the 9.8 m/s^2 due to gravity from the linear and vertical accelerations, I assume your everyday gyroscope outputs data in the form of change in degrees, so if it just sitting perfectly still it would just output 0 on all axis, but if it actually gives the current angle I would be surprised, and curious how this is done. So in conclusion, how could an arduino accurately know where down is?