What is the effect of mma7660 gravity accelerometer and gyroscope?
1. Gravity accelerometer mma7660
1. Function: Mma7660 is just a 3-axis g-sensor, it is mainly used to measure tilt angle, inertial force, impact force and vibration.
2. Working principle: mma7660 is a capacitive g-sensor. The capacitive g-sensor is mostly made by European and American manufacturers. Its technology is to make a comb-like structure on the surface of the wafer. When an action occurs, the deformation is determined by detecting the difference in capacitance. The value of acceleration.
Different from the piezoresistive type, it is difficult for the capacitive type to sense the changes of the three axes (X, Y, Z) at the same time in the same structure. Usually X, Y and Z are separated. (This is Why when the board is placed horizontally, no matter how to change the position of X and Y, there will be no interruption, because at this time it can only detect the change of the Z axis, it can not detect the change of X, Y, only when we put the board The change of X, Y can be detected only after tilting an angle). The piezoresistive type can sense three axis changes in the same structure.
3. Working mode: Mma7660 mainly has three working modes. (By setting the MODE register)
1). Standby mode
At this time, only I2C works and receives commands from the host. This mode is used to set the register. In other words, if you want to change the value of any register of mma7660, you must first enter the Standby mode. After setting, enter Active or Auto-Sleep mode.
2). AcTIve and Auto-Sleep (active and Auto-Sleep) mode
Mma7660 has two working states, one is high frequency sampling, the other is low frequency sampling. Why is it divided this way, in order to save power consumption, but maintain sufficient sensitivity during activities.
So the AcTIve mode of the mma7660 is actually divided into two modes, one is the pure AcTIve mode, that is, the high sampling frequency is kept unchanged after entering the AcTIve mode. There is also Active & Auto-Sleep mode, which means that the system enters high-frequency sampling first after activation. After a certain period of time, if no activity is detected, it enters low-frequency sampling, so it is called Auto-Sleep, Sleep and It’s not really Sleep, it just means reducing the sampling frequency.
Low-frequency sampling mode is also called Auto-Wake mode, which is automatic wake-up mode. It is not a sleep mode, it just reduces the sampling frequency.
3). Auto-Wake mode
After Auto-Sleep, it enters the low-frequency sampling mode. This mode is called Auto-Wake mode, that is, automatic wake-up mode. It is not a sleep mode, it just reduces the sampling frequency.
2. Gyroscope
After using g-sensor, I am very curious about its relationship with gyroscope.
In terms of motion sensing, the accelerometer is not bad for motions with varying amounts of motion, but the accuracy is not enough for even motion changes, and the gyroscope just makes up for this.
The principle of gyroscope is that for a rotating object, the direction pointed by the axis of rotation will not change when it is not affected by external forces. People use it to maintain direction based on this principle. When the gyroscope is working, it needs to give it a force to make it spin quickly, and then use a variety of methods to read the direction of the axis, and automatically transmit the data signal to the system.
After the object rotates at a high speed, its axis will have the stability of pointing.
Gyroscope is a kind of omnidirectional angle deviation detection instrument in three-dimensional space.
2.1 The function of the gyroscope on the model helicopter
The basic principle of helicopter flight is to use the variable angle of the main rotor to generate reverse thrust and ascend, but it will produce a torsion effect on the fuselage, so a tail rotor is needed to offset the torsion, and the fuselage is leveled. But how to make the tail rotor use the right angle to balance the fuselage? This uses a gyroscope, which can automatically make a compensation signal to the servo according to how much the fuselage swings, to change the angle of the tail rotor, and generate thrust to balance the fuselage. In the past, model helicopters did not have a gyroscope. It was difficult to match the throttle and main rotor angles. After starting, they would fly to the sky as soon as possible (because it is easier to control during flight). It is easy to crash. There are many types of gyroscopes used in helicopter models, including mechanical, electronic, and electronic automatic locking.
2.2 Using the gyroscope on the smartphone
Anyone who pays attention to IPHONE4 knows that its super selling point is the built-in gyroscope, which has both a gyroscope and a gravity accelerometer. The main purposes of gyroscopes are:
1). navigation. Gyroscopes have been used for navigation since they were invented. If combined with GPS, the navigation capabilities of mobile phones will reach an unprecedented level (electronic inertial navigation, but it cannot be without GPS calibration for a long time, otherwise it will deviate over time). In fact, many professional handheld GPSs are also equipped with gyroscopes. If the corresponding software is installed on the mobile phone, its navigation capability is no less than that of the navigators on many ships and airplanes.
2). Camera anti-shake. Match the camera on the phone
3). Sensors for various games. The gyroscope completely detects the movement of the player's hand, so as to realize the effects of various game operations.
4). Can be used as an input device, the gyroscope is equivalent to a stereo mouse.
For mobile phones equipped with gyroscopes, cameras, and various sensors, it has been transformed from a communication tool to an entertainment center, and then upgraded to a highly efficient production tool.
If you want to know more, our website has product specifications for gravity accelerometer, you can go to ALLICDATA ELECTRONICS LIMITED to get more information