Safety on a quadcopter: calibrate the compass and hold it with your hand

A month ago, we purchased a quadrocopter DJI Phantom 3 Advanced. The device gives a lot of pleasure to the whole family, especially when you return home after the flight and watch the recordings from a height on the big screen. But we experienced the strongest emotions when the drone lost control.

In general, with the purchase of such a neat, beautiful and technological helicopter itching to launch it up immediately. I do not consider myself to be the most reckless experimenters, but all that I initially wanted to learn from the operating manual is how to start the engines and what the levers on the console affect. Since before that there was little experience in managing a small drone, similar to Syma , then with Phantom, it seemed, there should be no management problems.


About any different drones, including on GT, they write quite a lot. But, after a month of operation, I want to note that the articles usually do not contain the warm feeling that this “pet” causes. He really is perceived as a rather obedient pet, which sometimes is capricious and gets into various troubles. Therefore, I will try to talk about how to take the drone on the handles so that everyone will be calmer. If you read too lazy, you can just watch the video at the end.
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An interesting idea was expressed in an interview by one designer from our company. The point is this: all these gadgets and widgets around us form a different from natural reality, in our opinion, augmented reality. If adults still somehow realize where and what, then the kids come to this world filled with drones, tablets and other equipment, feeling it, probably, completely to itself completely. Of course, I managed to dream about building a quadrocopter with my own hands. To my creation, I hardly would have remained such children's curiosity, which arises to a complex Chinese hand-made article. The DJI phantom arose in my life quite spontaneously, as if a hitherto unseen physical phenomenon, which I would like not only to use for its intended purpose, but also to experience it from the inside. It should be immediately emphasized that the kilogram machine with powerful propellers is really dangerous from all sides. However, the danger, as is known, is sharply reduced in the process of mastering the apparatus, especially mastering on the verge of safety.

Naturally, the instructions will write, they say, do not fly up to people and animals. They will not paint how to get out if the quadcopter has blown to people by an unexpected gust of wind. They will also write about what should not be launched in windy weather, but there may be no wind below, and at a height of one hundred and fifty meters it will already be significant. So people, whatever one may say, are studying this all willy-nilly. And will, as experience shows, is much more effective and interesting.

Someone will say that the price of a flying gadget in itself limits imagination to experiments, but even if this “someone” is in the majority, then the drones killed in the first flight will not be returned anyway. And in general, can any despicable money be there to cool off the fervor of a real Russian naturalist? Moreover, already spent money.

I was personally stopped by purely technical obstacles: the battery in the box was charged only 20%, and for some reason the DJI Go app did not show video from the camera on my old smartphone. While I was dealing with the video, the battery sat down even more. So, with the first flight of the Phantom, I didn’t come off the ground above one and a half meters.

Further tinkering with the video led to the idea to update the firmware. Then the night came, and after it - the working day. That's when I was fortunate enough to clear my brains of breathless traction and rush into the sky in full sail.

So, before launching a new quadrocopter on dangerous three-dimensional travels, I strongly recommend not reading the manuals, but look at YouTube for videos of falls and other unpleasant situations with multicopter. I was just going to see how people fly, more precisely, they are piloting drones, but the eye itself caught the pictures with signatures of the form “phantom crash”. After such clips, instructions are no longer readable, but, as it were, are re-read in search of important information. Therefore, in the evening I was calm and balanced. Fly, as it should, began in the novice mode. And when he turned it off, at first it significantly limited the height and range of the flight.

Most impressed by the video, showing how the Phantom is carried away into the unknown, caught up by a strong wind . There is in them some kind of anxiety and hopelessness that is not felt in the selection of amusing falls and collisions. Only one thought reassures: “If the video is uploaded, then the drone with the onboard flash drive was found.” But again, another worries: “What if someone else found him? But what if only the flash drive survived? ”To be honest, we also launched at significant air flow speeds, but the drone, we note, confronts them very confidently. It is hard to imagine what kind of winds were blowing in the above videos. There, probably, the operator himself demolished, and he still tried to control the drone. Although, once again, the upper air currents can be very different from the lower ones.

Looking through the video with beating and blown quadrocopters, I once noticed a simple recommendation: calibrate the compass before the flight - this will allow the Phantom to return to the point of take-off without any problems. Indeed, the return "home" is almost the most important function of the aircraft. Because when climbing 150 meters above the ground, even in a clear day sky, it is already difficult to see. And if you do not know the approximate sector of the solid angle, then just do not see. If the drone takes off to 250 meters and is horizontally removed to 500 meters, then there is no way to control it visually. In an unfamiliar monotonous landscape, you also cannot orient yourself with the video from his camera. I suspect that at the dawn of the copter, not one device was lost in the sky in this way. And we were lucky. Smart Chinese have built in such functionality that the quadrocopter returns home not only when asked for it, but also if it loses the signal from the console. By the way, in the city signal loss occurs regularly.

But back to the calibration. Once we went out into the yard of our own housing complex and calibrated the compass. The quadcopter's status table disappeared from the tablet screen, the engines started, and the rover soared into the sky. About sixty centimeters somewhere ... Immediately after takeoff, he was led somewhere to the side, into a tree. The operator was able to correctly respond and lead the machine from a collision. But the crazy drone continued hooliganism: at first, he almost got the operator together with the audience, and then safely crashed into another tree and fell upside down on the grass. Again, we must pay tribute to the Chinese: the screws are not broken, and in general, everything remains intact, except for a couple of scratches on board.

The mistake was to read the instructions more carefully. When calibrating the compass, the copter should be held no less than a meter above the ground, whereas I usually turned it, barely lifting it. But I learned about the correct method later. And then I thought that somewhere under the ground lies a magnetic anomaly. There, generally speaking, parking, so that, in principle, electromagnetic interference can be quite a lot. We simply moved to another place and, barely restraining the trembling in our knees, we again launched the beast. This time successfully.

But not quite usual. With a hand. In my opinion, it is useful to know that DJI Phantom 3 runs without problems if you hold it with one hand on the leg. It can be useful when running on any field with high grass. At the end of the video under this article it is shown how to land in this way, that is, to tame. Well, it is just useful to know the gravity and power of the quadrocopter just in case. When I first started from my hand, I just gave up the gas to hang the drone in the air and, without fully unclipping my fingers, made sure that it did not blow it away.

In addition, after the first blow to the tree, we immediately acquired protective frames for the propellers. They, of course, make the design cumbersome and unsuitable for quick disassembly, but so much calmer. By the way, on the same YouTube there are such videos where quadrocopters suddenly rush into the wall or into people for no apparent reason. This did not happen to us, but during filming near tall buildings, the apparatus does sometimes unpredictably chat. Tryndit, like a prozhzhennaya tradeswoman ... I suspect that the matter here is in complex air turbulence, which can be very rapid locally (a vivid example is a tornado). So let it be better to protect.

Thus, we calibrate the compass before each launch. Unfortunately, I have not yet understood how the status of a failed calibration is displayed in the DJI Go application. In any case, first take off thirty centimeters above the surface, check the handling and only then send the gadget on a long flight. Now, at least, I can easily catch and hold him in a situation of demolition.

In the process of studying the flight characteristics of the drone, we had the idea to make a small film about the life of these aircraft. Tale, of course, a lie, but it turned out funny. (Watch with sound.)



Uploader Many interesting comments have been formed, for which I am very grateful. Of course, the article didn’t pretend to be the ultimate truth, but I didn’t lose my value due to criticism for my taste. As for the calibration of the compass and, in general, a neat take-off, there is an extensive commentary by an experienced fly- driver fly4546 . I think this is too much, but for reference it is interesting. The other day, he himself took off from the parking lot on the roof of the building: from the floor Phantom refused to take off, because surrounded by such a quantity of iron, the roof of the compass was blown away, but it soared quietly from its hand and behaved absolutely predictably. I think Phantom brains are getting better, so a great deal of caution from previous generations is no longer relevant.