mpu6050.c File Reference

#include "mpu6050.h"
#include "i2cdev.h"

Include dependency graph for mpu6050.c:

Macros
#define	MIN_ACCE_ERROR   5
#define	MIN_GYRO_ERROR   5
#define	MAX_CALIBRATION_ATTEMPTS   20
#define	G_RAW_VALUE   16384

Functions
esp_err_t	i2c_master_init (void)
	Initialise the ESP32 I2C Driver in Master Mode. More...
esp_err_t	enable_mpu6050 (void)
	Initialise MPU-6050 (by sending the appropriate queued commands); Refer this for more information: https://invensense.tdk.com/wp-content/uploads/2015/02/MPU-6000-Datasheet1.pdf. More...
esp_err_t	mpu6050_read_acce (uint8_t *data_rd, size_t size)
	Get the accelerometer raw values (Ax, Ay, Az) into an 8-bit array Note that these raw values are actually 16-bit, split into MSB (Byte) and LSB (Byte), sent one after the other. More...
esp_err_t	mpu6050_read_gyro (uint8_t *data_rd, size_t size)
	Get the gyroscope raw values (Gx, Gy, Gz) into an 8-bit array Note that these raw values are actually 16-bit, split into MSB (Byte) and LSB (Byte), sent one after the other. More...
void	combine_msb_lsb_raw_data (uint8_t *buf_1, int16_t *buf_2)
	Combine two 8-bit values to a 16-bit one Note that EVEN indices in the input buffer represent the MSB (Byte) More...
void	compute_acce_angle (int16_t ax, int16_t ay, int16_t az, float *acce_angle)
	Compute the Euler angle (Pitch and Roll) from the accelerometer raw values Axes and Angles - X: Roll, Y: Pitch, Z: Yaw. More...
void	compute_gyro_angle (int16_t gx, int16_t gy, int16_t gz, float dt, float *gyro_angle)
	Compute the Euler angle (Pitch and Roll) from the gyroscope raw values Axes and Angles - X: Roll, Y: Pitch, Z: Yaw More on this here: https://philsal.co.uk/projects/imu-attitude-estimation. More...
esp_err_t	read_mpu6050_raw (int16_t *acce_raw_value, int16_t *gyro_raw_value)
	A wrapper for reading the 8-bit raw values from MPU and then combining them to their final form i.e. 16-bit. More...
void	complementary_filter (int16_t *acce_raw_value, int16_t *gyro_raw_value, float *complementary_angle, float *mpu_offset)
	Fuse the gyroscope and accelerometer angle in a complementary fashion More on this here: https://robotics.stackexchange.com/questions/10746/complimentary-filter-issues. More...
esp_err_t	avg_sensors (int16_t *acce_raw_value_avg, int16_t *gyro_raw_value_avg, const int16_t *acce_offs, const int16_t *gyro_offs)
	Helper function for the function calibrate_mpu6050() to calculate the average of the raw values. More...
esp_err_t	calibrate_mpu6050 ()
	Function to calculate the MPU offset for raw values. More...
esp_err_t	read_mpu6050 (float *euler_angle, float *mpu_offset)
	The ultimate function (application ready); takes in the input raw values and initial conditions and gives out the complementary pitch and roll angles. More...

Macro Definition Documentation

G_RAW_VALUE

#define G_RAW_VALUE   16384

MAX_CALIBRATION_ATTEMPTS

#define MAX_CALIBRATION_ATTEMPTS   20

MIN_ACCE_ERROR

#define MIN_ACCE_ERROR   5

MIN_GYRO_ERROR

#define MIN_GYRO_ERROR   5

Function Documentation

avg_sensors()

esp_err_t avg_sensors	(	int16_t *	acce_raw_value_avg,
		int16_t *	gyro_raw_value_avg,
		const int16_t *	acce_offs,
		const int16_t *	gyro_offs
	)

Helper function for the function calibrate_mpu6050() to calculate the average of the raw values.

Parameters

acce_raw_value_avg	Input array of accelerometer raw values (passed by reference) to be filled by the function.
gyro_raw_value_avg	Input array of gyroscope raw values (passed by reference) to be filled by the function.
acce_offs	Offset to be applied to the accelerometer raw values.
gyro_offs	Offset to be applied to the gyroscope raw values.

Returns

esp_err_t returns ESP_OK if successful, else ESP_FAIL

calibrate_mpu6050()

esp_err_t calibrate_mpu6050

(

)

Function to calculate the MPU offset for raw values.

Returns

esp_err_t returns ESP_OK if successful, else ESP_FAIL

combine_msb_lsb_raw_data()

void combine_msb_lsb_raw_data	(	uint8_t *	buf_1,
		int16_t *	buf_2
	)

Combine two 8-bit values to a 16-bit one Note that EVEN indices in the input buffer represent the MSB (Byte)

Parameters

buf_1	8-bit Input array of size 6
buf_2	16-bit Output array of size 3

complementary_filter()

void complementary_filter	(	int16_t *	acce_raw_value,
		int16_t *	gyro_raw_value,
		float *	complementary_angle,
		float *	mpu_offset
	)

Fuse the gyroscope and accelerometer angle in a complementary fashion More on this here: https://robotics.stackexchange.com/questions/10746/complimentary-filter-issues.

Parameters

acce_raw_value	Raw values from the accelerometer
gyro_raw_value	Raw values from the gyroscope
complementary_angle	Resultant fused and filtered angle
mpu_offset	Offset of the MPU (accelerometer) at rest position

compute_acce_angle()

void compute_acce_angle	(	int16_t	ax,
		int16_t	ay,
		int16_t	az,
		float *	acce_angle
	)

Compute the Euler angle (Pitch and Roll) from the accelerometer raw values Axes and Angles - X: Roll, Y: Pitch, Z: Yaw.

Parameters

ax	Raw accelerometer value (X-axis)
ay	Raw accelerometer value (Y-axis)
az	Raw accelerometer value (Z-axis)
acce_angle	Resultant angle array

compute_gyro_angle()

void compute_gyro_angle	(	int16_t	gx,
		int16_t	gy,
		int16_t	gz,
		float	dt,
		float *	gyro_angle
	)

Compute the Euler angle (Pitch and Roll) from the gyroscope raw values Axes and Angles - X: Roll, Y: Pitch, Z: Yaw More on this here: https://philsal.co.uk/projects/imu-attitude-estimation.

Parameters

gx	Raw gyroscope value (X-axis)
gy	Raw gyroscope value (Y-axis)
gz	Raw gyroscope value (Z-axis)
dt	Sampling time for gyroscope readings (interval between 2 readings)
gyro_angle	Resultant angle array

enable_mpu6050()

esp_err_t enable_mpu6050

(

void

)

Initialise MPU-6050 (by sending the appropriate queued commands); Refer this for more information: https://invensense.tdk.com/wp-content/uploads/2015/02/MPU-6000-Datasheet1.pdf.

Returns

esp_err_t returns ESP_OK if MPU-6050 initialised successfully, else the appropriate error code Refer this for more info on ESP32 I2C Error codes: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/i2c.html

i2c_master_init()

esp_err_t i2c_master_init

(

)

Initialise the ESP32 I2C Driver in Master Mode.

Returns

esp_err_t returns ESP_OK if I2C driver initialised properly, ESP_ERR_INVALID_ARG for Parameter error, ESP_FAIL Driver for install error

mpu6050_read_acce()

esp_err_t mpu6050_read_acce	(	uint8_t *	data_rd,
		size_t	size
	)

Get the accelerometer raw values (Ax, Ay, Az) into an 8-bit array Note that these raw values are actually 16-bit, split into MSB (Byte) and LSB (Byte), sent one after the other.

Parameters

data_rd	Buffer array for storing raw values
size	Size of the buffer array (6 in our case)

Returns

esp_err_t returns ESP_OK if acceleromter read successfully, else the appropriate error code

mpu6050_read_gyro()

esp_err_t mpu6050_read_gyro	(	uint8_t *	data_rd,
		size_t	size
	)

Get the gyroscope raw values (Gx, Gy, Gz) into an 8-bit array Note that these raw values are actually 16-bit, split into MSB (Byte) and LSB (Byte), sent one after the other.

Parameters

data_rd	Buffer array for storing raw values
size	Size of the buffer array (6 in our case)

Returns

esp_err_t returns ESP_OK if gyroscope read successfully, else the appropriate error code

read_mpu6050()

esp_err_t read_mpu6050	(	float *	euler_angle,
		float *	mpu_offset
	)

The ultimate function (application ready); takes in the input raw values and initial conditions and gives out the complementary pitch and roll angles.

Parameters

euler_angle	Input array of angles to store the results in (passed by reference)
mpu_offset	Initial conditions for the accelerometer and gyroscope (Angle at rest position)

Returns

esp_err_t returns ESP_OK if successful, else the appropriate error code

read_mpu6050_raw()

esp_err_t read_mpu6050_raw	(	int16_t *	acce_raw_value,
		int16_t *	gyro_raw_value
	)

A wrapper for reading the 8-bit raw values from MPU and then combining them to their final form i.e. 16-bit.

Parameters

acce_raw_value	16-bit array for storing the accelerometer raw values
gyro_raw_value	16-bit array for storing the gyroscope raw values

Returns

esp_err_t returns ESP_OK if successful, else the appropriate error code