Lesson 32 MPU6050 Gyro Acceleration Sensor

Introduction

The MPU-6050 is the world’s first and only 6-axis motion tracking devices designed for the low power, low cost, and high performance requirements of smartphones, tablets and wearable sensors.

Required Components

• 1 * Raspberry Pi

• 1 * Breadboard

• 1 * MPU-6050 module

• Several Jumper wires

Experimental Principle

In this experiment, use I2C to obtain the values of the three-axis acceleration sensor and three-axis gyroscope for MPU6050 and display them on the screen.

Experimental Procedures

Step 1: Build the circuit.

Raspberry Pi	GPIO Extension Board	MPU-6050 Module
SCL	SCL1	SCL
SDA	SDA1	SDA
3.3V	3V3	VCC
GND	GND	GND

Step 2: Setup I2C (see Appendix. If you have set I2C, skip this step.)

For C Users:

Step 3: Change directory.

cd /home/pi/SunFounder_SensorKit_for_RPi2/C/32_mpu6050/

Step 4: Compile.

gcc 32_mpu6050.c -lwiringPi -lm

Note

If it does not work after running, or there is an error prompt wiringPi.h: No such file or directory, please refer to WiringPi to install it.

Step 5: Run.

sudo ./a.out

Code

#include  <wiringPiI2C.h>
#include <wiringPi.h>
#include  <stdio.h>
#include  <math.h>

int fd;
int acclX, acclY, acclZ;
int gyroX, gyroY, gyroZ;
double acclX_scaled, acclY_scaled, acclZ_scaled;
double gyroX_scaled, gyroY_scaled, gyroZ_scaled;

int read_word_2c(int addr)
{
int val;
val = wiringPiI2CReadReg8(fd, addr);
val = val << 8;
val += wiringPiI2CReadReg8(fd, addr+1);
if (val >= 0x8000)
    val = -(65536 - val);

return val;
}

double dist(double a, double b)
{
return sqrt((a*a) + (b*b));
}

double get_y_rotation(double x, double y, double z)
{
double radians;
radians = atan2(x, dist(y, z));
return -(radians * (180.0 / M_PI));
}

double get_x_rotation(double x, double y, double z)
{
double radians;
radians = atan2(y, dist(x, z));
return (radians * (180.0 / M_PI));
}

int main()
{
fd = wiringPiI2CSetup (0x68);
wiringPiI2CWriteReg8 (fd,0x6B,0x00);//disable sleep mode
printf("set 0x6B=%X\n",wiringPiI2CReadReg8 (fd,0x6B));

while(1) {

    gyroX = read_word_2c(0x43);
    gyroY = read_word_2c(0x45);
    gyroZ = read_word_2c(0x47);

    gyroX_scaled = gyroX / 131.0;
    gyroY_scaled = gyroY / 131.0;
    gyroZ_scaled = gyroZ / 131.0;

    //Print values for the X, Y, and Z axes of the gyroscope sensor.
    printf("My gyroX_scaled: %f\n", gyroX_scaled);
    printf("My gyroY_scaled: %f\n", gyroY_scaled);
    printf("My gyroZ_scaled: %f\n", gyroZ_scaled);

    acclX = read_word_2c(0x3B);
    acclY = read_word_2c(0x3D);
    acclZ = read_word_2c(0x3F);

    acclX_scaled = acclX / 16384.0;
    acclY_scaled = acclY / 16384.0;
    acclZ_scaled = acclZ / 16384.0;

    //Print the X, Y, and Z values of the acceleration sensor.
    printf("My acclX_scaled: %f\n", acclX_scaled);
    printf("My acclY_scaled: %f\n", acclY_scaled);
    printf("My acclZ_scaled: %f\n", acclZ_scaled);

    printf("My X rotation: %f\n", get_x_rotation(acclX_scaled, acclY_scaled, acclZ_scaled));
    printf("My Y rotation: %f\n", get_y_rotation(acclX_scaled, acclY_scaled, acclZ_scaled));


    delay(100);
}
return 0;
}

For Python Users:

Step 3: Change directory.

cd /home/pi/SunFounder_SensorKit_for_RPi2/Python/

Step 4: Run.

sudo python3 32_mpu6050.py

Note

• If you get the error FileNotFoundError: [Errno 2] No such file or directory: '/dev/i2c-1', you need to setup I2C (see Appendix -> I2C Configuration).

• If you get ModuleNotFoundError: No module named 'smbus2' error, please run the command: sudo pip3 install smbus2.

• If the error OSError: [Errno 121] Remote I/O appears, it means the module is miswired or the module is broken.

• If the module is connected correctly and still has the error TimeoutError: [Errno 110] Connection timed out, it means that the module is broken, please contact service@sunfounder.com. It is also possible to test if the I2C address appears with the command i2cdetect -y 1 if you have the I2C tools installed (sudo apt-get install i2c-tools).

Code

#!/usr/bin/python3
import smbus2 as smbus
import math
import time

# Power management registers
power_mgmt_1 = 0x6b
power_mgmt_2 = 0x6c

def read_byte(adr):
    return bus.read_byte_data(address, adr)

def read_word(adr):
    high = bus.read_byte_data(address, adr)
    low = bus.read_byte_data(address, adr+1)
    val = (high << 8) + low
    return val

def read_word_2c(adr):
    val = read_word(adr)
    if (val >= 0x8000):
        return -((65535 - val) + 1)
    else:
        return val

def dist(a,b):
    return math.sqrt((a*a)+(b*b))

def get_y_rotation(x,y,z):
    radians = math.atan2(x, dist(y,z))
    return -math.degrees(radians)

def get_x_rotation(x,y,z):
    radians = math.atan2(y, dist(x,z))
    return math.degrees(radians)


bus = smbus.SMBus(1) # or bus = smbus.SMBus(1) for Revision 2 boards
address = 0x68       # This is the address value read via the i2cdetect command

# Now wake the 6050 up as it starts in sleep mode
bus.write_byte_data(address, power_mgmt_1, 0)

while True:
    time.sleep(0.1)
    gyro_xout = read_word_2c(0x43)
    gyro_yout = read_word_2c(0x45)
    gyro_zout = read_word_2c(0x47)

    print ("gyro_xout : ", gyro_xout, " scaled: ", (gyro_xout / 131))
    print ("gyro_yout : ", gyro_yout, " scaled: ", (gyro_yout / 131))
    print ("gyro_zout : ", gyro_zout, " scaled: ", (gyro_zout / 131))

    accel_xout = read_word_2c(0x3b)
    accel_yout = read_word_2c(0x3d)
    accel_zout = read_word_2c(0x3f)

    accel_xout_scaled = accel_xout / 16384.0
    accel_yout_scaled = accel_yout / 16384.0
    accel_zout_scaled = accel_zout / 16384.0

    print ("accel_xout: ", accel_xout, " scaled: ", accel_xout_scaled)
    print ("accel_yout: ", accel_yout, " scaled: ", accel_yout_scaled)
    print ("accel_zout: ", accel_zout, " scaled: ", accel_zout_scaled)

    print ("x rotation: " , get_x_rotation(accel_xout_scaled, accel_yout_scaled, accel_zout_scaled))
    print ("y rotation: " , get_y_rotation(accel_xout_scaled, accel_yout_scaled, accel_zout_scaled))

    time.sleep(0.5)

Now you can see the values of the acceleration sensor, gyroscope, and XY-axis rotation read by MPU6050 printed on the screen constantly.