How does the gyroscope that is indispensable to smartphones work?

If you place a spinning top on a table, it will fall in one direction, but if you spin it, it will stand firmly on the table and will not fall as long as it keeps spinning.

The stability of a spinning top is directly related to its rotation speed. The faster the rotation speed, the more stable the top. This is because a spinning object has an axis of rotation. The direction of the axis of rotation is not easy to change. This is determined by the characteristics of the spinning object. The faster the rotation speed, the more difficult it is to change the direction of the axis of rotation. So when we provide a fulcrum for a spinning top, the gyroscope will rotate vertically on the fulcrum, and the axis of rotation will always point upwards. However, if we place the spinning top on this fulcrum at a certain tilt angle, it will maintain the original tilt angle and rotate on the fulcrum. At the same time, the gyroscope itself will also make a circular motion around the fulcrum.

Based on the characteristics of the gyroscope, humans designed another thing, that is, the gyroscope.

The gyroscope looks very similar to a spinning top, but in fact it is just a spinning top mounted on a universal bracket. Since the direction of the rotating axis of a spinning top is difficult to change, no matter how we rotate the universal bracket, the gyroscope in the center can always remain stable without changing direction. This seems very strange, but our ancients actually made something similar a long time ago. If you like to watch some ancient costume palace fighting dramas, you will find that the concubines in the drama always hang a spherical hollow heater with charcoal fire in it in winter. Why don't these charcoal fires pour out and burn people?

The reason why the charcoal fire in the ancient stove would not spill out is because the structure of the stove is a universal bracket with a charcoal basin in the center. No matter how the external structure shakes, the charcoal basin inside can remain stable, so the charcoal fire will not fall out.

The gyroscope we are talking about is actually a gyroscope replaced with the charcoal basin in the middle of the spherical stove. So what is the use of a gyroscope? Its function is to measure the attitude of an object. Because the direction of the gyroscope at the center of the gyroscope will not change, when we place a gyroscope in an object, we only need to measure the angles in various directions between the external bracket of the gyroscope and the gyroscope to determine the specific attitude of an object. In daily life, many things require the use of gyroscopes, from navigation to aerospace, and of course our mobile phones.

The gyroscope is an indispensable and important component of smartphones. Without it, most functions of smartphones cannot be realized because many functions require precise understanding of the specific posture of the phone.

Although mobile phones cannot do without gyroscopes, no matter how you look at it, our mobile phones do not seem to be equipped with this thing, because the space inside the mobile phone is really limited, and it seems that there is no place to install this thing. In fact, if we take the mobile phone apart, we really can't see the gyroscope. Why is this? The gyroscope installed in the mobile phone is different from the gyroscope we just talked about. Although it is also called a gyroscope, it has nothing to do with gyroscopes. From the appearance, it is a small black square with a side length of only a few millimeters.

This small black square has a name, called "micro-electromechanical gyroscope".

Although the MEMS gyroscope is also called a gyroscope, it has nothing to do with a gyroscope, either externally or internally. The reason why it can measure the posture of an object is that it uses the Coriolis force. The Coriolis force was proposed by the French meteorologist Coriolis. In short, in a rotating system, if there is an object moving in a straight line, it will be affected by the rotating system, and the moving path will be deflected and become a curve. The earth is rotating, so the earth is such a rotating system. Since the earth rotates from west to east, in the northern hemisphere, no matter which direction the wind blows from, it will deflect to the right, while in the southern hemisphere, it is just the opposite, and the wind will deflect to the left.

Now that we understand the Coriolis force, we can talk about the MEMS gyroscope.

The main body of the MEMS gyroscope is a mass block. This mass block will oscillate back and forth under the action of alternating voltage. This movement is essentially a linear motion. When the gyroscope starts to rotate, it will be affected by the Coriolis force and the horizontal oscillating gyroscope will deflect. That is to say, it not only has horizontal movement, but also vertical movement. The change in the movement mode will cause a slight change in the capacitance value, and by sensing this slight change, the change in the object's posture can be understood. Of course, a single MEMS gyroscope can only sense posture changes in one direction, but if two or three are installed in a mobile phone, the posture of the mobile phone can be accurately identified in all directions. After all, this thing is very small and does not take up much space.

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