- \r\n
- Measuring principle<\/a><\/li>\r\n
- Technical characteristics<\/a><\/li>\r\n<\/ul>\r\n<\/li>\r\n
- Control without library<\/a>\r\n
- \r\n
- Minimal sketch<\/a><\/li>\r\n
- Extended sketch<\/a><\/li>\r\n
- Interrupts<\/a><\/li>\r\n<\/ul>\r\n<\/li>\r\n
- Control with library<\/a>\r\n
- \r\n
- Adafruit_MPU6050 Library<\/a><\/li>\r\n
- MPU6500_light<\/a><\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n\n
If you just want to get started quickly, you can go directly to the libraries.<\/a><\/p>\r\n\n
Basics<\/h2>\n\n
The measuring principle of the MPU6050<\/h3>\n\n
In the context of accelerometers, you often come across the terms “3-axis”, “6-axis” or even “9-axis sensors”. Don’t worry, we are not leaving the three-dimensional world. Instead, one or more sensors, which are effective in three dimensions, are used in parallel. And in the case of the MPU6050, this is an accelerometer and a gyroscope. 9-axis sensors usually have an additional geomagnetic field sensor.<\/p>\r\n\n
Gyroscopes<\/h4>\n\n
The classical gyroscope<\/a> works like a toy whipping top. Everyone knows it from childhood and also its effect. The rotation stabilizes it (precession) and therefore the attempt to tilt its axis of rotation requires force. And exactly with this, you can determine the inclination or angular acceleration of an object (e.g. an airplane or ship). Compared to the simple whipping tops, the gyroscope is mounted in a frame. An exemplary toy gyroscope:<\/p>\r\n\n
![\"A](\"https:\/\/wolles-elektronikkiste.de\/wp-content\/uploads\/2020\/11\/Kreiselspielzeug-1024x611.png\")
<\/a>A toy gyroscope<\/figcaption><\/figure>\n\n In the MPU6050 there is of course no part which is spinning (and fortunately, you don\u2019t have to move it manually ;-)). Such sensors are based on”Micro-Electric-Mechanical Systems<\/a>” (MEMS). In the case of gyroscopes, these are moving parts that change their position within a fixed frame when accelerated. The distance change results in a change in capacity. In principle, this is how it looks:<\/p>\r\n\n
![\"The](\"https:\/\/wolles-elektronikkiste.de\/wp-content\/uploads\/2021\/01\/Accel_sensor_principle-1024x311.png\")
<\/a>The measuring principle of the MPU6050<\/figcaption><\/figure>\n\n An older technique is based on the piezo effect, so it uses pressure changes as the measuring principle.<\/p>\r\n\n
Accelerometers<\/h4>\n\n
An accelerometer works according to the same principle. The difference is that the accelerometer detects acceleration in the x-, y-, and z-axis directions<\/strong>, while the gyroscope detects motion about<\/strong> the axes. When the module is in the idle state, the gyroscope returns zero for x, y and z. The acceleration sensor, on the other hand, detects the acceleration due to gravity even at rest (in the z-direction when the module is flat).<\/p>\r\n
The modules have printed the position of the x- and y-axis. The z-axis is the perpendicular on the module.<\/a><\/p>\r\n\n
![\"MPU6050](\"https:\/\/wolles-elektronikkiste.de\/wp-content\/uploads\/2020\/11\/MPU6050-1024x564.jpg\")
<\/a>MPU6050 Module<\/figcaption><\/figure>\n\n Technical Data \/ Features<\/h3>\n\n
The most important technical data of the MPU6050 are:<\/p>\r\n
- \r\n
- Power supply <\/strong>(VDD\/GND): the module has an LDO voltage converter (see also here<\/a>), and hence it can be supplied with 3.3 volts as well as with 5 volts.<\/li>\r\n
- Power consumption<\/strong>(module): approx. 5.1 mA, in sleep mode approx. 1.4 mA (own measurements). If you remove the LED, the consumption is reduced to 3.7 mA or 33 \u00b5A in sleep mode.<\/li>\r\n
- Accelerometer<\/strong>: 16-bit resolution, measuring ranges +\/- 2, 4, 8 or 16 g; with g = earth acceleration, not grams!<\/li>\r\n
- Gyroscope<\/strong>: 16-bit resolution, measuring ranges: +\/- 250, 500, 1000 or 2000\u00b0\/s.<\/li>\r\n
- Communication <\/strong>(SDA\/SCL): I2C, address 0x68 (AD0 = GND or unconnected) or 0x69 (AD0 = HIGH)<\/li>\r\n
- Interrupts<\/strong>: data ready, free fall, acceleration limit;<\/li>\r\n
- Connection of additional sensors<\/strong> (XDA \/ XCL): I will not go into this.<\/li>\r\n<\/ul>\r\n
For more information, see the data sheet<\/a> and the register map<\/a>.<\/a><\/p>\r\n\n
Control of the MPU6050 without library<\/h2>\n\n
The minimal sketch<\/h3>\n\n
If you can live with the defaults (+\/-2 g, +\/-250\u00b0\/s), then you might get by with the following sketch (based on: Arduino Playground<\/a>).\u00a0<\/p>\r\n
I\u2019m not going to go through all the details of the sketch, just so much:<\/p>\r\n
- \r\n
- First, the MPU6050 is awakened by the entry of a zero in the \u201cPower Management 1\u201d register.<\/li>\r\n
- The MPU6050 continuously produces results for acceleration, gyroscope and temperature.<\/li>\r\n
- Since the result registers are sequential, they can be read out conveniently in one go.<\/li>\r\n
- Only raw data is output (-32767 to + 32767).<\/li>\r\n<\/ul>\r\n\n\r\n
#include \"Wire.h\" \r\n\r\n#define MPU6050_ADDR 0x68 \/\/ Alternatively set AD0 to HIGH --> Address = 0x69\r\n\r\nint16_t accX, accY, accZ, gyroX, gyroY, gyroZ, tRaw; \/\/ Raw register values (accelaration, gyroscope, temperature)\r\nchar result[7]; \/\/ temporary variable used in convert function\r\n\r\nvoid setup() {\r\n Serial.begin(9600);\r\n Wire.begin();\r\n Wire.beginTransmission(MPU6050_ADDR);\r\n Wire.write(0x6B); \/\/ PWR_MGMT_1 register\r\n Wire.write(0); \/\/ wake up!\r\n Wire.endTransmission(true);\r\n}\r\nvoid loop() {\r\n Wire.beginTransmission(MPU6050_ADDR);\r\n Wire.write(0x3B); \/\/ starting with register 0x3B (ACCEL_XOUT_H)\r\n Wire.endTransmission(false); \/\/ the parameter indicates that the Arduino will send a restart. \r\n \/\/ As a result, the connection is kept active.\r\n Wire.requestFrom(MPU6050_ADDR, 14, true); \/\/ request a total of 7*2=14 registers\r\n \r\n \/\/ \"Wire.read()<<8 | Wire.read();\" means two registers are read and stored in the same int16_t variable\r\n accX = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x3B (ACCEL_XOUT_H) and 0x3C (ACCEL_XOUT_L)\r\n accY = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x3D (ACCEL_YOUT_H) and 0x3E (ACCEL_YOUT_L)\r\n accZ = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x3F (ACCEL_ZOUT_H) and 0x40 (ACCEL_ZOUT_L)\r\n tRaw = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x41 (TEMP_OUT_H) and 0x42 (TEMP_OUT_L)\r\n gyroX = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x43 (GYRO_XOUT_H) and 0x44 (GYRO_XOUT_L)\r\n gyroY = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x45 (GYRO_YOUT_H) and 0x46 (GYRO_YOUT_L)\r\n gyroZ = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x47 (GYRO_ZOUT_H) and 0x48 (GYRO_ZOUT_L)\r\n \r\n Serial.print(\"AcX = \"); Serial.print(toStr(accX));\r\n Serial.print(\" | AcY = \"); Serial.print(toStr(accY));\r\n Serial.print(\" | AcZ = \"); Serial.print(toStr(accZ));\r\n \/\/ from data sheet:\r\n Serial.print(\" | tmp = \"); Serial.print((tRaw + 12412.0) \/ 340.0);\r\n Serial.print(\" | GyX = \"); Serial.print(toStr(gyroX));\r\n Serial.print(\" | GyY = \"); Serial.print(toStr(gyroY));\r\n Serial.print(\" | GyZ = \"); Serial.print(toStr(gyroZ));\r\n Serial.println();\r\n \r\n delay(1000);\r\n}\r\n\r\nchar* toStr(int16_t character) { \/\/ converts int16 to string and formatting\r\n sprintf(result, \"%6d\", character);\r\n return result;\r\n}<\/pre>\r\n<\/p>\r\n<\/div>\r\n\n
Below you can see the output of the sketch on the serial monitor. Since the MPU6050 was placed flat in the x\/y plane, all results except acceleration in the z-direction (acceleration due to gravity) should be zero. This is not the case, but the result is not bad in first approximation.<\/p>\r\n
You can adjust the initial values by entering offset values in corresponding registers. Some libraries have implemented this option, others have not.<\/p>\r\n\n
![\"Output](\"https:\/\/wolles-elektronikkiste.de\/wp-content\/uploads\/2020\/11\/Output_minimum_sketch-1024x339.png\")
<\/a>Output of the minimal sketch for the MPU6050<\/figcaption><\/figure>\n\n For completeness, I have shown the circuit here. We will need the LED and the line to the interrupt later. Pull-ups for the I2C lines (3.3 V) are integrated on the module. <\/a><\/p>\r\n\n
![\"Wiring](\"https:\/\/wolles-elektronikkiste.de\/wp-content\/uploads\/2020\/11\/MPU6050_Wiring-1024x629.png\")
<\/a>Wiring the MPU6050 with the Arduino<\/figcaption><\/figure>\n\n The extended Minimalsketch <\/h3>\n\n
I then added a few extras to the minimum sketch:<\/p>\r\n
- \r\n
setAccRange()<\/code> sets the measuring range for acceleration.<\/li>\r\nsetGyrRange()<\/code> sets the measuring range for the gyroscope.<\/li>\r\nMCP6050_wakeUp()<\/code> awakens the MPU6050.\r\n- \r\n
- It needs some time to wake up, only after 30 ms I could determine meaningful gyroscope values.<\/li>\r\n<\/ul>\r\n<\/li>\r\n
MCP6050_sleep<\/code> sends the MPU6050 to sleep.<\/li>\r\n<\/ul>\r\nBy applying intermittent sleep, I could reduce the power consumption from 5.2 to 1.4 mA with the following sketch. If you then remove the LED, the consumption drops to less than 0.1 mA.<\/p>\r\n
If you want to understand the sketch in terms of register settings, take a look at the register map<\/a>.<\/p>\r\n\n
\r\n#include \"Wire.h\" \r\n\r\n#define MPU6050_ADDR 0x68 \/\/ Alternatively set AD0 to HIGH --> Address = 0x69\r\n#define MPU6050_GYRO_CONFIG 0x1B \/\/\/< Gyro specfic configuration register\r\n#define MPU6050_ACCEL_CONFIG 0x1C\r\n#define MPU6050_ACCEL_XOUT_H 0x3B\r\n#define MPU6050_PWR_MGT_1 0x6B\r\n#define MPU6050_SLEEP 0x06\r\n\r\ntypedef enum {\r\n MPU6050_ACC_RANGE_2G, \/\/ +\/- 2g (default)\r\n MPU6050_ACC_RANGE_4G, \/\/ +\/- 4g\r\n MPU6050_ACC_RANGE_8G, \/\/ +\/- 8g\r\n MPU6050_ACC_RANGE_16G \/\/ +\/- 16g\r\n} mpu6050_acc_range;\r\n\r\ntypedef enum {\r\n MPU6050_GYR_RANGE_250, \/\/ +\/- 250 deg\/s (default)\r\n MPU6050_GYR_RANGE_500, \/\/ +\/- 500 deg\/s\r\n MPU6050_GYR_RANGE_1000, \/\/ +\/- 1000 deg\/s\r\n MPU6050_GYR_RANGE_2000 \/\/ +\/- 2000 deg\/s\r\n} mpu6050_gyr_range;\r\n\r\nint16_t accX, accY, accZ, gyroX, gyroY, gyroZ, tRaw; \/\/ Raw register values (accelaration, gyroscope, temperature)\r\nchar result[7];\r\n\r\nvoid setup() {\r\n Serial.begin(9600);\r\n Wire.begin();\r\n MPU6050_wakeUp();\r\n setAccRange(MPU6050_ACC_RANGE_16G);\r\n setGyrRange(MPU6050_GYR_RANGE_250);\r\n}\r\n\r\nvoid loop() {\r\n MPU6050_wakeUp();\r\n Wire.beginTransmission(MPU6050_ADDR);\r\n Wire.write(MPU6050_ACCEL_XOUT_H); \/\/ starting with register ACCEL_XOUT_H\r\n Wire.endTransmission(false); \/\/ the parameter indicates that the Arduino will send a restart. \r\n \/\/ As a result, the connection is kept active.\r\n Wire.requestFrom(MPU6050_ADDR, 7*2, true); \/\/ request a total of 7*2=14 registers\r\n \r\n \/\/ \"Wire.read()<<8 | Wire.read();\" means two registers are read and stored in the same variable\r\n accX = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x3B (ACCEL_XOUT_H) and 0x3C (ACCEL_XOUT_L)\r\n accY = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x3D (ACCEL_YOUT_H) and 0x3E (ACCEL_YOUT_L)\r\n accZ = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x3F (ACCEL_ZOUT_H) and 0x40 (ACCEL_ZOUT_L)\r\n tRaw = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x41 (TEMP_OUT_H) and 0x42 (TEMP_OUT_L)\r\n gyroX = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x43 (GYRO_XOUT_H) and 0x44 (GYRO_XOUT_L)\r\n gyroY = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x45 (GYRO_YOUT_H) and 0x46 (GYRO_YOUT_L)\r\n gyroZ = Wire.read()<<8 | Wire.read(); \/\/ reading registers: 0x47 (GYRO_ZOUT_H) and 0x48 (GYRO_ZOUT_L)\r\n MPU6050_sleep();\r\n \r\n \/\/ print out data\r\n Serial.print(\"AcX = \"); Serial.print(toStr(accX));\r\n Serial.print(\" | AcY = \"); Serial.print(toStr(accY));\r\n Serial.print(\" | AcZ = \"); Serial.print(toStr(accZ));\r\n \/\/ the following equation was taken from the documentation [MPU-6000\/MPU-6050 Register Map and Description, p.30]\r\n Serial.print(\" | tmp = \"); Serial.print((tRaw + 12412.0) \/ 340.0);\r\n Serial.print(\" | GyX = \"); Serial.print(toStr(gyroX));\r\n Serial.print(\" | GyY = \"); Serial.print(toStr(gyroY));\r\n Serial.print(\" | GyZ = \"); Serial.print(toStr(gyroZ));\r\n Serial.println();\r\n \r\n delay(1000);\r\n}\r\n\r\nchar* toStr(int16_t i) { \/\/ int16 to string plus output format\r\n sprintf(result, \"%6d\", i);\r\n return result;\r\n}\r\n\r\nvoid setAccRange(mpu6050_acc_range range){\r\n writeRegister(MPU6050_ACCEL_CONFIG, range<<3);\r\n}\r\n\r\nvoid setGyrRange(mpu6050_gyr_range range){\r\n writeRegister(MPU6050_GYRO_CONFIG, range<<3);\r\n}\r\n\r\nvoid MPU6050_wakeUp(){\r\n writeRegister(MPU6050_PWR_MGT_1, 0); \r\n delay(30); \/\/ give him time to wake up, gyro needs quite a while to stabilize;\r\n}\r\n\r\nvoid MPU6050_sleep(){\r\n writeRegister(MPU6050_PWR_MGT_1, 1<<MPU6050_SLEEP); \r\n}\r\n\r\nvoid writeRegister(uint16_t reg, byte value){\r\n Wire.beginTransmission(MPU6050_ADDR);\r\n Wire.write(reg); \r\n Wire.write(value); \r\n Wire.endTransmission(true);\r\n}<\/pre>\r\n<\/p>\r\n<\/div>\r\n\n
Since I have chosen the range +\/- 16 g in the example, the measured values for the acceleration in z-direction decrease to one eighth:<\/p>\r\n\n
![\"Output](\"https:\/\/wolles-elektronikkiste.de\/wp-content\/uploads\/2020\/11\/Output_minimum_plus_sketch-1024x339.png\")
<\/a>Output of the extended minimal sketch<\/figcaption><\/figure>\n\n I could have added more features, but at some point it gets confusing and then libraries are the better choice.<\/p>\r\n\n
Conversion of raw data<\/h3>\n\n
For the conversion of the raw values to values in g, the following applies:<\/p>\r\n\n
<\/p>\r\n
<\/span> <\/span>
![\"\[](\"https:\/\/wolles-elektronikkiste.de\/wp-content\/ql-cache\/quicklatex.com-604abe755f7b921d1d4a6bcab33a5532_l3.png\" "\\"Rendered")
<\/p><\/p>\r\n\nThe conversion of the gyroscope data into angular velocities is done according to the following formula (derived from the data sheet):<\/a><\/p>\r\n\n
<\/span> <\/span>
![\"\[](\"https:\/\/wolles-elektronikkiste.de\/wp-content\/ql-cache\/quicklatex.com-ada29571dea7903a365066d28181591b_l3.png\" "\\"Rendered")
<\/p><\/p>\r\n\nInterrupts<\/h3>\n\n
Perhaps the following very short video of the “Magic Push Button” will whet your appetite for the interrupt function, which by the way was not implemented in any library I looked at.<\/p>\r\n\n
- Power consumption<\/strong>(module): approx. 5.1 mA, in sleep mode approx. 1.4 mA (own measurements). If you remove the LED, the consumption is reduced to 3.7 mA or 33 \u00b5A in sleep mode.<\/li>\r\n
- MPU6500_light<\/a><\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n\n
- Extended sketch<\/a><\/li>\r\n
- Technical characteristics<\/a><\/li>\r\n<\/ul>\r\n<\/li>\r\n