ORIGINAL POST IN ITALIAN LANGUAGE FROM QUADRICOTTERO NEWS: http://www.quadricottero.com/2015/07/il-bebop-drone-impazzisce-se-dallombra.html
For someone could be a way to do magic tricks but for the majority of those who use a Bebop is an annoying effect of which probably have not even noticed thinking is normal behavior or the cause of an error of piloting.
We are talking about a lack of flight behavior of the Bebop, seemingly inexplicable, which was recently reported by some users and on which we have investigated to discover the cause and find a solution.
Basically it happens that if the Bebop is flying in a gray area and is struck by the sun, suddenly drastically lowers the flight altitude as if the sun goes in the shade increases considerably the flight altitude. What happens at a short distance from the ground where the ultrasonic sensor that should keep the height, but the data fusion with the barometer so influence the final calculation that causes this effect.
The reports concern, perhaps only a coincidence, bebop yellow and so placing a specimen we tested it. And it went exactly as reported, making shadow in the area faired polystyrene, which is located under the GPS, bebop rooms share alone then dropped when the sun strikes.
THE CAUSE OF BEBOP CLIMBING DOWN AND HE HIT BY SHADOW AND THE SUN
After detecting the problem, which affects the behavior of flight whenever there is' a change of light intensity from the sun (even just a cloud or fly / tack against the sun) we removed the hull polystyrene and found that under the GPS module is installed, the barometric pressure sensor MS 5607
Despite being under the keel and angled downward, the 'MS5607 suffers from a little-understood problem, perhaps unknown even by engineers at Parrot who have chosen the materials for the fairing of the Bebop.
When hit by infrared / ultraviolet sunlight, this type of sensor (it was also successful on the DJI NAZA M V1 which mounted the 'MS5611 VIDEO ) varies the pressure reading indicating a false and deceiving the autopilot so he thinks to be a height different from that of a few moments before. E 'in this way that the bebop is a change in altitude sudden that, depending on the intensity of the instantaneous variation of the brightness, can be of several meters.
We have demonstrated in our video, just shade even with one hand, in the area of the hull where below is the GPS and the barometric sensor, the bebop gets up suddenly share. Analyzing the hull polystyrene we found that this material passes the light. Ours was yellow but we think that even the red and blue do go the same way the sun's rays.
To resolve must make sure that the sensor is in an environment where where is not hit by the light (from a change of brightness) and then a solution is to screen externally or internally the hull waiting for the Parrot notices the problem and propose an official solution.
IF YOU HAVE A BEBOP DO A TEST AND LET US KNOW Commenting THIS ARTICLE
THE VIDEO OF A USER WHO HAS OCCURRED THE PROBLEM
Comments
This is not a new problem, Ardupilot dealt with this about 2 years ago.
This is known behavior for all MEMS based barometric sensors, and the only realistic solution is to shield the sensor from exposure to sunlight. Without a proper casing, a quick fix is to cover the barometric sensor with some dense black foam material that will block sunlight and still let trough air.