/* MPU6050 Basic Example with IMU
by: Kris Winer
date: May 10, 2014
license: Beerware - Use this code however you'd like. If you
find it useful you can buy me a beer some time.
Demonstrate MPU-6050 basic functionality including initialization, accelerometer trimming, sleep mode functionality as well as
parameterizing the register addresses. Added display functions to allow display to on breadboard monitor.
No DMP use. We just want to get out the accelerations, temperature, and gyro readings.
SDA and SCL should have external pull-up resistors (to 3.3V).
10k resistors worked for me. They should be on the breakout
board.
Hardware setup:
MPU6050 Breakout --------- Arduino
3.3V --------------------- 3.3V
SDA ----------------------- A4
SCL ----------------------- A5
GND ---------------------- GND
Note: The MPU6050 is an I2C sensor and uses the Arduino Wire library.
Because the sensor is not 5V tolerant, we are using a 3.3 V 8 MHz Pro Mini or a 3.3 V Teensy 3.1.
We have disabled the internal pull-ups used by the Wire library in the Wire.h/twi.c utility file.
We are also using the 400 kHz fast I2C mode by setting the TWI_FREQ to 400000L /twi.h utility file.
*/
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>
// Using NOKIA 5110 monochrome 84 x 48 pixel display
// pin 9 - Serial clock out (SCLK)
// pin 8 - Serial data out (DIN)
// pin 7 - Data/Command select (D/C)
// pin 5 - LCD chip select (CS)
// pin 6 - LCD reset (RST)
Adafruit_PCD8544 display = Adafruit_PCD8544(9, 8, 7, 5, 6);
// Define registers per MPU6050, Register Map and Descriptions, Rev 4.2, 08/19/2013 6 DOF Motion sensor fusion device
// Invensense Inc., www.invensense.com
// See also MPU-6050 Register Map and Descriptions, Revision 4.0, RM-MPU-6050A-00, 9/12/2012 for registers not listed in
// above document; the MPU6050 and MPU 9150 are virtually identical but the latter has an on-board magnetic sensor
//
#define XGOFFS_TC 0x00 // Bit 7 PWR_MODE, bits 6:1 XG_OFFS_TC, bit 0 OTP_BNK_VLD
#define YGOFFS_TC 0x01
#define ZGOFFS_TC 0x02
#define X_FINE_GAIN 0x03 // [7:0] fine gain
#define Y_FINE_GAIN 0x04
#define Z_FINE_GAIN 0x05
#define XA_OFFSET_H 0x06 // User-defined trim values for accelerometer
#define XA_OFFSET_L_TC 0x07
#define YA_OFFSET_H 0x08
#define YA_OFFSET_L_TC 0x09
#define ZA_OFFSET_H 0x0A
#define ZA_OFFSET_L_TC 0x0B
#define SELF_TEST_X 0x0D
#define SELF_TEST_Y 0x0E
#define SELF_TEST_Z 0x0F
#define SELF_TEST_A 0x10
#define XG_OFFS_USRH 0x13 // User-defined trim values for gyroscope
#define XG_OFFS_USRL 0x14
#define YG_OFFS_USRH 0x15
#define YG_OFFS_USRL 0x16
#define ZG_OFFS_USRH 0x17
#define ZG_OFFS_USRL 0x18
#define SMPLRT_DIV 0x19
#define CONFIG 0x1A
#define GYRO_CONFIG 0x1B
#define ACCEL_CONFIG 0x1C
#define FF_THR 0x1D // Free-fall
#define FF_DUR 0x1E // Free-fall
#define MOT_THR 0x1F // Motion detection threshold bits [7:0]
#define MOT_DUR 0x20 // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms
#define ZMOT_THR 0x21 // Zero-motion detection threshold bits [7:0]
#define ZRMOT_DUR 0x22 // Duration counter threshold for zero motion interrupt generation, 16 Hz rate, LSB = 64 ms
#define FIFO_EN 0x23
#define I2C_MST_CTRL 0x24
#define I2C_SLV0_ADDR 0x25
#define I2C_SLV0_REG 0x26
#define I2C_SLV0_CTRL 0x27
#define I2C_SLV1_ADDR 0x28
#define I2C_SLV1_REG 0x29
#define I2C_SLV1_CTRL 0x2A
#define I2C_SLV2_ADDR 0x2B
#define I2C_SLV2_REG 0x2C
#define I2C_SLV2_CTRL 0x2D
#define I2C_SLV3_ADDR 0x2E
#define I2C_SLV3_REG 0x2F
#define I2C_SLV3_CTRL 0x30
#define I2C_SLV4_ADDR 0x31
#define I2C_SLV4_REG 0x32
#define I2C_SLV4_DO 0x33
#define I2C_SLV4_CTRL 0x34
#define I2C_SLV4_DI 0x35
#define I2C_MST_STATUS 0x36
#define INT_PIN_CFG 0x37
#define INT_ENABLE 0x38
#define DMP_INT_STATUS 0x39 // Check DMP interrupt
#define INT_STATUS 0x3A
#define ACCEL_XOUT_H 0x3B
#define ACCEL_XOUT_L 0x3C
#define ACCEL_YOUT_H 0x3D
#define ACCEL_YOUT_L 0x3E
#define ACCEL_ZOUT_H 0x3F
#define ACCEL_ZOUT_L 0x40
#define TEMP_OUT_H 0x41
#define TEMP_OUT_L 0x42
#define GYRO_XOUT_H 0x43
#define GYRO_XOUT_L 0x44
#define GYRO_YOUT_H 0x45
#define GYRO_YOUT_L 0x46
#define GYRO_ZOUT_H 0x47
#define GYRO_ZOUT_L 0x48
#define EXT_SENS_DATA_00 0x49
#define EXT_SENS_DATA_01 0x4A
#define EXT_SENS_DATA_02 0x4B
#define EXT_SENS_DATA_03 0x4C
#define EXT_SENS_DATA_04 0x4D
#define EXT_SENS_DATA_05 0x4E
#define EXT_SENS_DATA_06 0x4F
#define EXT_SENS_DATA_07 0x50
#define EXT_SENS_DATA_08 0x51
#define EXT_SENS_DATA_09 0x52
#define EXT_SENS_DATA_10 0x53
#define EXT_SENS_DATA_11 0x54
#define EXT_SENS_DATA_12 0x55
#define EXT_SENS_DATA_13 0x56
#define EXT_SENS_DATA_14 0x57
#define EXT_SENS_DATA_15 0x58
#define EXT_SENS_DATA_16 0x59
#define EXT_SENS_DATA_17 0x5A
#define EXT_SENS_DATA_18 0x5B
#define EXT_SENS_DATA_19 0x5C
#define EXT_SENS_DATA_20 0x5D
#define EXT_SENS_DATA_21 0x5E
#define EXT_SENS_DATA_22 0x5F
#define EXT_SENS_DATA_23 0x60
#define MOT_DETECT_STATUS 0x61
#define I2C_SLV0_DO 0x63
#define I2C_SLV1_DO 0x64
#define I2C_SLV2_DO 0x65
#define I2C_SLV3_DO 0x66
#define I2C_MST_DELAY_CTRL 0x67
#define SIGNAL_PATH_RESET 0x68
#define MOT_DETECT_CTRL 0x69
#define USER_CTRL 0x6A // Bit 7 enable DMP, bit 3 reset DMP
#define PWR_MGMT_1 0x6B // Device defaults to the SLEEP mode
#define PWR_MGMT_2 0x6C
#define DMP_BANK 0x6D // Activates a specific bank in the DMP
#define DMP_RW_PNT 0x6E // Set read/write pointer to a specific start address in specified DMP bank
#define DMP_REG 0x6F // Register in DMP from which to read or to which to write
#define DMP_REG_1 0x70
#define DMP_REG_2 0x71
#define FIFO_COUNTH 0x72
#define FIFO_COUNTL 0x73
#define FIFO_R_W 0x74
#define WHO_AM_I_MPU6050 0x75 // Should return 0x68
// Using the GY-521 breakout board, I set ADO to 0 by grounding through a 4k7 resistor
// Seven-bit device address is 110100 for ADO = 0 and 110101 for ADO = 1
#define ADO 0
#if ADO
#define MPU6050_ADDRESS 0x69 // Device address when ADO = 1
#else
#define MPU6050_ADDRESS 0x68 // Device address when ADO = 0
#endif
// Set initial input parameters
enum Ascale {
AFS_2G = 0,
AFS_4G,
AFS_8G,
AFS_16G
};
enum Gscale {
GFS_250DPS = 0,
GFS_500DPS,
GFS_1000DPS,
GFS_2000DPS
};
// Specify sensor full scale
int Gscale = GFS_250DPS;
int Ascale = AFS_2G;
float aRes, gRes; // scale resolutions per LSB for the sensors
// Pin definitions
#define intPin 3 // These can be changed, 2 and 3 are the Arduinos ext int pins
#define ledPin 13 // Blink LED on Teensy or Pro Mini when updating
boolean SerialDebug = true;
int16_t accelCount[3]; // Stores the 16-bit signed accelerometer sensor output
float ax, ay, az; // Stores the real accel value in g's
int16_t gyroCount[3]; // Stores the 16-bit signed gyro sensor output
float gx, gy, gz; // Stores the real gyro value in degrees per seconds
float gyroBias[3] = {0, 0, 0}, accelBias[3] = {0, 0, 0}; // Bias corrections for gyro and accelerometer
int16_t tempCount; // Stores the real internal chip temperature in degrees Celsius
float temperature;
float SelfTest[6];
uint32_t delt_t = 0; // used to control display output rate
uint32_t count = 0; // used to control display output rate
float sum = 0.; // For averaging the filter update rate
uint32_t sumCount= 0; // For averaging the filter update rate
// parameters for 6 DoF sensor fusion calculations
#define GyroMeasError PI * (40.0f / 180.0f) // gyroscope measurement error in rads/s (start at 60 deg/s), then reduce after ~10 s to 3
#define beta sqrt(3.0f / 4.0f) * GyroMeasError // compute beta
#define GyroMeasDrift PI * (2.0f / 180.0f) // gyroscope measurement drift in rad/s/s (start at 2.0 deg/s/s)
#define zeta sqrt(3.0f / 4.0f) * GyroMeasDrift // compute zeta, the other free parameter in the Madgwick scheme usually set to a small or zero value
float pitch, yaw, roll;
float deltat = 0.0f; // integration interval for both filter schemes
uint32_t lastUpdate = 0, Now = 0; // used to calculate integration interval
float q[4] = {1.0f, 0.0f, 0.0f, 0.0f}; // vector to hold quaternion
void setup()
{
Wire.begin();
Serial.begin(38400);
// Set up the interrupt pin, its set as active high, push-pull
pinMode(intPin, FALLING);
digitalWrite(intPin, LOW);
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, HIGH);
display.begin(); // Initialize the display
display.setContrast(58); // Set the contrast
display.setRotation(2); // 0 or 2) width = width, 1 or 3) width = height, swapped etc.
// Start device display with ID of sensor
display.clearDisplay();
display.setTextSize(2);
display.setCursor(0,0); display.print("MPU6050");
display.setTextSize(1);
display.setCursor(0, 20); display.print("6-DOF 16-bit");
display.setCursor(0, 30); display.print("motion sensor");
display.setCursor(20,40); display.print("60 ug LSB");
display.display();
delay(1000);
// Set up for data display
display.setTextSize(1); // Set text size to normal, 2 is twice normal etc.
display.setTextColor(BLACK); // Set pixel color; 1 on the monochrome screen
display.clearDisplay(); // clears the screen and buffer
// Read the WHO_AM_I register, this is a good test of communication
uint8_t c = readByte(MPU6050_ADDRESS, WHO_AM_I_MPU6050); // Read WHO_AM_I register for MPU-6050
display.setCursor(20,0); display.print("MPU6050");
display.setCursor(0,10); display.print("I AM");
display.setCursor(0,20); display.print(c, HEX);
display.setCursor(0,30); display.print("I Should Be");
display.setCursor(0,40); display.print(0x68, HEX);
display.display();
delay(1000);
if (c == 0x68) // WHO_AM_I should always be 0x68
{
Serial.println("MPU6050 is online...");
MPU6050SelfTest(SelfTest); // Start by performing self test and reporting values
if(SerialDebug) {
Serial.print("x-axis self test: acceleration trim within : "); Serial.print(SelfTest[0],1); Serial.println("% of factory value");
Serial.print("y-axis self test: acceleration trim within : "); Serial.print(SelfTest[1],1); Serial.println("% of factory value");
Serial.print("z-axis self test: acceleration trim within : "); Serial.print(SelfTest[2],1); Serial.println("% of factory value");
Serial.print("x-axis self test: gyration trim within : "); Serial.print(SelfTest[3],1); Serial.println("% of factory value");
Serial.print("y-axis self test: gyration trim within : "); Serial.print(SelfTest[4],1); Serial.println("% of factory value");
Serial.print("z-axis self test: gyration trim within : "); Serial.print(SelfTest[5],1); Serial.println("% of factory value");
}
if(SelfTest[0] < 1.0f && SelfTest[1] < 1.0f && SelfTest[2] < 1.0f && SelfTest[3] < 1.0f && SelfTest[4] < 1.0f && SelfTest[5] < 1.0f) {
display.clearDisplay();
display.setCursor(0, 30); display.print("Pass Selftest!");
display.display();
delay(1000);
calibrateMPU6050(gyroBias, accelBias); // Calibrate gyro and accelerometers, load biases in bias registers
display.clearDisplay();
display.setCursor(0, 0); display.print("MPU6050 bias");
display.setCursor(0, 8); display.print(" x y z ");
display.setCursor(0, 16); display.print((int)(1000*accelBias[0]));
display.setCursor(24, 16); display.print((int)(1000*accelBias[1]));
display.setCursor(48, 16); display.print((int)(1000*accelBias[2]));
display.setCursor(72, 16); display.print("mg");
display.setCursor(0, 24); display.print(gyroBias[0], 1);
display.setCursor(24, 24); display.print(gyroBias[1], 1);
display.setCursor(48, 24); display.print(gyroBias[2], 1);
display.setCursor(66, 24); display.print("o/s");
display.display();
delay(1000);
initMPU6050(); Serial.println("MPU6050 initialized for active data mode...."); // Initialize device for active mode read of acclerometer, gyroscope, and temperature
}
else
{
Serial.print("Could not connect to MPU6050: 0x");
Serial.println(c, HEX);
while(1) ; // Loop forever if communication doesn't happen
}
}
}
void loop()
{
// If data ready bit set, all data registers have new data
if(readByte(MPU6050_ADDRESS, INT_STATUS) & 0x01) { // check if data ready interrupt
readAccelData(accelCount); // Read the x/y/z adc values
getAres();
// Now we'll calculate the accleration value into actual g's
ax = (float)accelCount[0]*aRes; // get actual g value, this depends on scale being set
ay = (float)accelCount[1]*aRes;
az = (float)accelCount[2]*aRes;
readGyroData(gyroCount); // Read the x/y/z adc values
getGres();
// Calculate the gyro value into actual degrees per second
gx = (float)gyroCount[0]*gRes; // get actual gyro value, this depends on scale being set
gy = (float)gyroCount[1]*gRes;
gz = (float)gyroCount[2]*gRes;
tempCount = readTempData(); // Read the x/y/z adc values
temperature = ((float) tempCount) / 340. + 36.53; // Temperature in degrees Centigrade
}
Now = micros();
deltat = ((Now - lastUpdate)/1000000.0f); // set integration time by time elapsed since last filter update
lastUpdate = Now;
sum += deltat;
sumCount++;
// Pass gyro rate as rad/s
MadgwickQuaternionUpdate(ax, ay, az, gx*PI/180.0f, gy*PI/180.0f, gz*PI/180.0f);
// Serial print and/or display at 0.5 s rate independent of data rates
delt_t = millis() - count;
if (delt_t > 500) { // update LCD once per half-second independent of read rate
digitalWrite(ledPin, !digitalRead(ledPin));
if(SerialDebug) {
Serial.print("ax = "); Serial.print((int)1000*ax);
Serial.print(" ay = "); Serial.print((int)1000*ay);
Serial.print(" az = "); Serial.print((int)1000*az); Serial.println(" mg");
Serial.print("gx = "); Serial.print( gx, 1);
Serial.print(" gy = "); Serial.print( gy, 1);
Serial.print(" gz = "); Serial.print( gz, 1); Serial.println(" deg/s");
Serial.print("q0 = "); Serial.print(q[0]);
Serial.print(" qx = "); Serial.print(q[1]);
Serial.print(" qy = "); Serial.print(q[2]);
Serial.print(" qz = "); Serial.println(q[3]);
}
// Define output variables from updated quaternion---these are Tait-Bryan angles, commonly used in aircraft orientation.
// In this coordinate system, the positive z-axis is down toward Earth.
// Yaw is the angle between Sensor x-axis and Earth magnetic North (or true North if corrected for local declination, looking down on the sensor positive yaw is counterclockwise.
// Pitch is angle between sensor x-axis and Earth ground plane, toward the Earth is positive, up toward the sky is negative.
// Roll is angle between sensor y-axis and Earth ground plane, y-axis up is positive roll.
// These arise from the definition of the homogeneous rotation matrix constructed from quaternions.
// Tait-Bryan angles as well as Euler angles are non-commutative; that is, the get the correct orientation the rotations must be
// applied in the correct order which for this configuration is yaw, pitch, and then roll.
// For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles which has additional links.
yaw = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]);
pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
roll = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]);
pitch *= 180.0f / PI;
yaw *= 180.0f / PI;
roll *= 180.0f / PI;
if(SerialDebug) {
Serial.print("Yaw, Pitch, Roll: ");
Serial.print(yaw, 2);
Serial.print(", ");
Serial.print(pitch, 2);
Serial.print(", ");
Serial.println(roll, 2);
Serial.print("average rate = "); Serial.print((float) sumCount/sum, 2); Serial.println(" Hz");
}
display.clearDisplay();
display.setCursor(0, 0); display.print(" x y z ");
display.setCursor(0, 8); display.print((int)(1000*ax));
display.setCursor(24, 8); display.print((int)(1000*ay));
display.setCursor(48, 8); display.print((int)(1000*az));
display.setCursor(72, 8); display.print("mg");
display.setCursor(0, 16); display.print((int)(gx));
display.setCursor(24, 16); display.print((int)(gy));
display.setCursor(48, 16); display.print((int)(gz));
display.setCursor(66, 16); display.print("o/s");
display.setCursor(0, 32); display.print((int)(yaw));
display.setCursor(24, 32); display.print((int)(pitch));
display.setCursor(48, 32); display.print((int)(roll));
display.setCursor(66, 32); display.print("ypr");
display.setCursor(0, 40); display.print("rt: "); display.print((float)sumCount /sum, 2); display.print(" Hz");
display.display();
count = millis();
sum = 0;
sumCount = 0;
}
}
//===================================================================================================================
//====== Set of useful function to access acceleratio, gyroscope, and temperature data
//===================================================================================================================
void getGres() {
switch (Gscale)
{
// Possible gyro scales (and their register bit settings) are:
// 250 DPS (00), 500 DPS (01), 1000 DPS (10), and 2000 DPS (11).
case GFS_250DPS:
gRes = 250.0/32768.0;
break;
case GFS_500DPS:
gRes = 500.0/32768.0;
break;
case GFS_1000DPS:
gRes = 1000.0/32768.0;
break;
case GFS_2000DPS:
gRes = 2000.0/32768.0;
break;
}
}
void getAres() {
switch (Ascale)
{
// Possible accelerometer scales (and their register bit settings) are:
// 2 Gs (00), 4 Gs (01), 8 Gs (10), and 16 Gs (11).
case AFS_2G:
aRes = 2.0/32768.0;
break;
case AFS_4G:
aRes = 4.0/32768.0;
break;
case AFS_8G:
aRes = 8.0/32768.0;
break;
case AFS_16G:
aRes = 16.0/32768.0;
break;
}
}
void readAccelData(int16_t * destination)
{
uint8_t rawData[6]; // x/y/z accel register data stored here
readBytes(MPU6050_ADDRESS, ACCEL_XOUT_H, 6, &rawData[0]); // Read the six raw data registers into data array
destination[0] = (int16_t)((rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
destination[1] = (int16_t)((rawData[2] << 8) | rawData[3]) ;
destination[2] = (int16_t)((rawData[4] << 8) | rawData[5]) ;
}
void readGyroData(int16_t * destination)
{
uint8_t rawData[6]; // x/y/z gyro register data stored here
readBytes(MPU6050_ADDRESS, GYRO_XOUT_H, 6, &rawData[0]); // Read the six raw data registers sequentially into data array
destination[0] = (int16_t)((rawData[0] << 8) | rawData[1]) ; // Turn the MSB and LSB into a signed 16-bit value
destination[1] = (int16_t)((rawData[2] << 8) | rawData[3]) ;
destination[2] = (int16_t)((rawData[4] << 8) | rawData[5]) ;
}
int16_t readTempData()
{
uint8_t rawData[2]; // x/y/z gyro register data stored here
readBytes(MPU6050_ADDRESS, TEMP_OUT_H, 2, &rawData[0]); // Read the two raw data registers sequentially into data array
return ((int16_t)rawData[0]) << 8 | rawData[1] ; // Turn the MSB and LSB into a 16-bit value
}
// Configure the motion detection control for low power accelerometer mode
void LowPowerAccelOnlyMPU6050()
{
// The sensor has a high-pass filter necessary to invoke to allow the sensor motion detection algorithms work properly
// Motion detection occurs on free-fall (acceleration below a threshold for some time for all axes), motion (acceleration
// above a threshold for some time on at least one axis), and zero-motion toggle (acceleration on each axis less than a
// threshold for some time sets this flag, motion above the threshold turns it off). The high-pass filter takes gravity out
// consideration for these threshold evaluations; otherwise, the flags would be set all the time!
uint8_t c = readByte(MPU6050_ADDRESS, PWR_MGMT_1);
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c & ~0x30); // Clear sleep and cycle bits [5:6]
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c | 0x30); // Set sleep and cycle bits [5:6] to zero to make sure accelerometer is running
c = readByte(MPU6050_ADDRESS, PWR_MGMT_2);
writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c & ~0x38); // Clear standby XA, YA, and ZA bits [3:5]
writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c | 0x00); // Set XA, YA, and ZA bits [3:5] to zero to make sure accelerometer is running
c = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x07); // Clear high-pass filter bits [2:0]
// Set high-pass filter to 0) reset (disable), 1) 5 Hz, 2) 2.5 Hz, 3) 1.25 Hz, 4) 0.63 Hz, or 7) Hold
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c | 0x00); // Set ACCEL_HPF to 0; reset mode disbaling high-pass filter
c = readByte(MPU6050_ADDRESS, CONFIG);
writeByte(MPU6050_ADDRESS, CONFIG, c & ~0x07); // Clear low-pass filter bits [2:0]
writeByte(MPU6050_ADDRESS, CONFIG, c | 0x00); // Set DLPD_CFG to 0; 260 Hz bandwidth, 1 kHz rate
c = readByte(MPU6050_ADDRESS, INT_ENABLE);
writeByte(MPU6050_ADDRESS, INT_ENABLE, c & ~0xFF); // Clear all interrupts
writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x40); // Enable motion threshold (bits 5) interrupt only
// Motion detection interrupt requires the absolute value of any axis to lie above the detection threshold
// for at least the counter duration
writeByte(MPU6050_ADDRESS, MOT_THR, 0x80); // Set motion detection to 0.256 g; LSB = 2 mg
writeByte(MPU6050_ADDRESS, MOT_DUR, 0x01); // Set motion detect duration to 1 ms; LSB is 1 ms @ 1 kHz rate
delay (100); // Add delay for accumulation of samples
c = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x07); // Clear high-pass filter bits [2:0]
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c | 0x07); // Set ACCEL_HPF to 7; hold the initial accleration value as a referance
c = readByte(MPU6050_ADDRESS, PWR_MGMT_2);
writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c & ~0xC7); // Clear standby XA, YA, and ZA bits [3:5] and LP_WAKE_CTRL bits [6:7]
writeByte(MPU6050_ADDRESS, PWR_MGMT_2, c | 0x47); // Set wakeup frequency to 5 Hz, and disable XG, YG, and ZG gyros (bits [0:2])
c = readByte(MPU6050_ADDRESS, PWR_MGMT_1);
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c & ~0x20); // Clear sleep and cycle bit 5
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, c | 0x20); // Set cycle bit 5 to begin low power accelerometer motion interrupts
}
void initMPU6050()
{
// wake up device
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // Clear sleep mode bit (6), enable all sensors
delay(100); // Delay 100 ms for PLL to get established on x-axis gyro; should check for PLL ready interrupt
// get stable time source
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01); // Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
// Configure Gyro and Accelerometer
// Disable FSYNC and set accelerometer and gyro bandwidth to 44 and 42 Hz, respectively;
// DLPF_CFG = bits 2:0 = 010; this sets the sample rate at 1 kHz for both
// Maximum delay time is 4.9 ms corresponding to just over 200 Hz sample rate
writeByte(MPU6050_ADDRESS, CONFIG, 0x03);
// Set sample rate = gyroscope output rate/(1 + SMPLRT_DIV)
writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x04); // Use a 200 Hz rate; the same rate set in CONFIG above
// Set gyroscope full scale range
// Range selects FS_SEL and AFS_SEL are 0 - 3, so 2-bit values are left-shifted into positions 4:3
uint8_t c = readByte(MPU6050_ADDRESS, GYRO_CONFIG);
writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c & ~0xE0); // Clear self-test bits [7:5]
writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c & ~0x18); // Clear AFS bits [4:3]
writeByte(MPU6050_ADDRESS, GYRO_CONFIG, c | Gscale << 3); // Set full scale range for the gyro
// Set accelerometer configuration
c = readByte(MPU6050_ADDRESS, ACCEL_CONFIG);
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0xE0); // Clear self-test bits [7:5]
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c & ~0x18); // Clear AFS bits [4:3]
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, c | Ascale << 3); // Set full scale range for the accelerometer
// Configure Interrupts and Bypass Enable
// Set interrupt pin active high, push-pull, and clear on read of INT_STATUS, enable I2C_BYPASS_EN so additional chips
// can join the I2C bus and all can be controlled by the Arduino as master
writeByte(MPU6050_ADDRESS, INT_PIN_CFG, 0x22);
writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x01); // Enable data ready (bit 0) interrupt
}
// Function which accumulates gyro and accelerometer data after device initialization. It calculates the average
// of the at-rest readings and then loads the resulting offsets into accelerometer and gyro bias registers.
void calibrateMPU6050(float * dest1, float * dest2)
{
uint8_t data[12]; // data array to hold accelerometer and gyro x, y, z, data
uint16_t ii, packet_count, fifo_count;
int32_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0};
// reset device, reset all registers, clear gyro and accelerometer bias registers
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x80); // Write a one to bit 7 reset bit; toggle reset device
delay(100);
// get stable time source
// Set clock source to be PLL with x-axis gyroscope reference, bits 2:0 = 001
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x01);
writeByte(MPU6050_ADDRESS, PWR_MGMT_2, 0x00);
delay(200);
// Configure device for bias calculation
writeByte(MPU6050_ADDRESS, INT_ENABLE, 0x00); // Disable all interrupts
writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00); // Disable FIFO
writeByte(MPU6050_ADDRESS, PWR_MGMT_1, 0x00); // Turn on internal clock source
writeByte(MPU6050_ADDRESS, I2C_MST_CTRL, 0x00); // Disable I2C master
writeByte(MPU6050_ADDRESS, USER_CTRL, 0x00); // Disable FIFO and I2C master modes
writeByte(MPU6050_ADDRESS, USER_CTRL, 0x0C); // Reset FIFO and DMP
delay(15);
// Configure MPU6050 gyro and accelerometer for bias calculation
writeByte(MPU6050_ADDRESS, CONFIG, 0x01); // Set low-pass filter to 188 Hz
writeByte(MPU6050_ADDRESS, SMPLRT_DIV, 0x00); // Set sample rate to 1 kHz
writeByte(MPU6050_ADDRESS, GYRO_CONFIG, 0x00); // Set gyro full-scale to 250 degrees per second, maximum sensitivity
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, 0x00); // Set accelerometer full-scale to 2 g, maximum sensitivity
uint16_t gyrosensitivity = 131; // = 131 LSB/degrees/sec
uint16_t accelsensitivity = 16384; // = 16384 LSB/g
// Configure FIFO to capture accelerometer and gyro data for bias calculation
writeByte(MPU6050_ADDRESS, USER_CTRL, 0x40); // Enable FIFO
writeByte(MPU6050_ADDRESS, FIFO_EN, 0x78); // Enable gyro and accelerometer sensors for FIFO (max size 1024 bytes in MPU-6050)
delay(80); // accumulate 80 samples in 80 milliseconds = 960 bytes
// At end of sample accumulation, turn off FIFO sensor read
writeByte(MPU6050_ADDRESS, FIFO_EN, 0x00); // Disable gyro and accelerometer sensors for FIFO
readBytes(MPU6050_ADDRESS, FIFO_COUNTH, 2, &data[0]); // read FIFO sample count
fifo_count = ((uint16_t)data[0] << 8) | data[1];
packet_count = fifo_count/12;// How many sets of full gyro and accelerometer data for averaging
for (ii = 0; ii < packet_count; ii++) {
int16_t accel_temp[3] = {0, 0, 0}, gyro_temp[3] = {0, 0, 0};
readBytes(MPU6050_ADDRESS, FIFO_R_W, 12, &data[0]); // read data for averaging
accel_temp[0] = (int16_t) (((int16_t)data[0] << 8) | data[1] ) ; // Form signed 16-bit integer for each sample in FIFO
accel_temp[1] = (int16_t) (((int16_t)data[2] << 8) | data[3] ) ;
accel_temp[2] = (int16_t) (((int16_t)data[4] << 8) | data[5] ) ;
gyro_temp[0] = (int16_t) (((int16_t)data[6] << 8) | data[7] ) ;
gyro_temp[1] = (int16_t) (((int16_t)data[8] << 8) | data[9] ) ;
gyro_temp[2] = (int16_t) (((int16_t)data[10] << 8) | data[11]) ;
accel_bias[0] += (int32_t) accel_temp[0]; // Sum individual signed 16-bit biases to get accumulated signed 32-bit biases
accel_bias[1] += (int32_t) accel_temp[1];
accel_bias[2] += (int32_t) accel_temp[2];
gyro_bias[0] += (int32_t) gyro_temp[0];
gyro_bias[1] += (int32_t) gyro_temp[1];
gyro_bias[2] += (int32_t) gyro_temp[2];
}
accel_bias[0] /= (int32_t) packet_count; // Normalize sums to get average count biases
accel_bias[1] /= (int32_t) packet_count;
accel_bias[2] /= (int32_t) packet_count;
gyro_bias[0] /= (int32_t) packet_count;
gyro_bias[1] /= (int32_t) packet_count;
gyro_bias[2] /= (int32_t) packet_count;
if(accel_bias[2] > 0L) {accel_bias[2] -= (int32_t) accelsensitivity;} // Remove gravity from the z-axis accelerometer bias calculation
else {accel_bias[2] += (int32_t) accelsensitivity;}
// Construct the gyro biases for push to the hardware gyro bias registers, which are reset to zero upon device startup
data[0] = (-gyro_bias[0]/4 >> 8) & 0xFF; // Divide by 4 to get 32.9 LSB per deg/s to conform to expected bias input format
data[1] = (-gyro_bias[0]/4) & 0xFF; // Biases are additive, so change sign on calculated average gyro biases
data[2] = (-gyro_bias[1]/4 >> 8) & 0xFF;
data[3] = (-gyro_bias[1]/4) & 0xFF;
data[4] = (-gyro_bias[2]/4 >> 8) & 0xFF;
data[5] = (-gyro_bias[2]/4) & 0xFF;
// Push gyro biases to hardware registers
writeByte(MPU6050_ADDRESS, XG_OFFS_USRH, data[0]);
writeByte(MPU6050_ADDRESS, XG_OFFS_USRL, data[1]);
writeByte(MPU6050_ADDRESS, YG_OFFS_USRH, data[2]);
writeByte(MPU6050_ADDRESS, YG_OFFS_USRL, data[3]);
writeByte(MPU6050_ADDRESS, ZG_OFFS_USRH, data[4]);
writeByte(MPU6050_ADDRESS, ZG_OFFS_USRL, data[5]);
dest1[0] = (float) gyro_bias[0]/(float) gyrosensitivity; // construct gyro bias in deg/s for later manual subtraction
dest1[1] = (float) gyro_bias[1]/(float) gyrosensitivity;
dest1[2] = (float) gyro_bias[2]/(float) gyrosensitivity;
// Construct the accelerometer biases for push to the hardware accelerometer bias registers. These registers contain
// factory trim values which must be added to the calculated accelerometer biases; on boot up these registers will hold
// non-zero values. In addition, bit 0 of the lower byte must be preserved since it is used for temperature
// compensation calculations. Accelerometer bias registers expect bias input as 2048 LSB per g, so that
// the accelerometer biases calculated above must be divided by 8.
int32_t accel_bias_reg[3] = {0, 0, 0}; // A place to hold the factory accelerometer trim biases
readBytes(MPU6050_ADDRESS, XA_OFFSET_H, 2, &data[0]); // Read factory accelerometer trim values
accel_bias_reg[0] = (int16_t) ((int16_t)data[0] << 8) | data[1];
readBytes(MPU6050_ADDRESS, YA_OFFSET_H, 2, &data[0]);
accel_bias_reg[1] = (int16_t) ((int16_t)data[0] << 8) | data[1];
readBytes(MPU6050_ADDRESS, ZA_OFFSET_H, 2, &data[0]);
accel_bias_reg[2] = (int16_t) ((int16_t)data[0] << 8) | data[1];
uint32_t mask = 1uL; // Define mask for temperature compensation bit 0 of lower byte of accelerometer bias registers
uint8_t mask_bit[3] = {0, 0, 0}; // Define array to hold mask bit for each accelerometer bias axis
for(ii = 0; ii < 3; ii++) {
if(accel_bias_reg[ii] & mask) mask_bit[ii] = 0x01; // If temperature compensation bit is set, record that fact in mask_bit
}
// Construct total accelerometer bias, including calculated average accelerometer bias from above
accel_bias_reg[0] -= (accel_bias[0]/8); // Subtract calculated averaged accelerometer bias scaled to 2048 LSB/g (16 g full scale)
accel_bias_reg[1] -= (accel_bias[1]/8);
accel_bias_reg[2] -= (accel_bias[2]/8);
data[0] = (accel_bias_reg[0] >> 8) & 0xFF;
data[1] = (accel_bias_reg[0]) & 0xFF;
data[1] = data[1] | mask_bit[0]; // preserve temperature compensation bit when writing back to accelerometer bias registers
data[2] = (accel_bias_reg[1] >> 8) & 0xFF;
data[3] = (accel_bias_reg[1]) & 0xFF;
data[3] = data[3] | mask_bit[1]; // preserve temperature compensation bit when writing back to accelerometer bias registers
data[4] = (accel_bias_reg[2] >> 8) & 0xFF;
data[5] = (accel_bias_reg[2]) & 0xFF;
data[5] = data[5] | mask_bit[2]; // preserve temperature compensation bit when writing back to accelerometer bias registers
// Push accelerometer biases to hardware registers
writeByte(MPU6050_ADDRESS, XA_OFFSET_H, data[0]);
writeByte(MPU6050_ADDRESS, XA_OFFSET_L_TC, data[1]);
writeByte(MPU6050_ADDRESS, YA_OFFSET_H, data[2]);
writeByte(MPU6050_ADDRESS, YA_OFFSET_L_TC, data[3]);
writeByte(MPU6050_ADDRESS, ZA_OFFSET_H, data[4]);
writeByte(MPU6050_ADDRESS, ZA_OFFSET_L_TC, data[5]);
// Output scaled accelerometer biases for manual subtraction in the main program
dest2[0] = (float)accel_bias[0]/(float)accelsensitivity;
dest2[1] = (float)accel_bias[1]/(float)accelsensitivity;
dest2[2] = (float)accel_bias[2]/(float)accelsensitivity;
}
// Accelerometer and gyroscope self test; check calibration wrt factory settings
void MPU6050SelfTest(float * destination) // Should return percent deviation from factory trim values, +/- 14 or less deviation is a pass
{
uint8_t rawData[4];
uint8_t selfTest[6];
float factoryTrim[6];
// Configure the accelerometer for self-test
writeByte(MPU6050_ADDRESS, ACCEL_CONFIG, 0xF0); // Enable self test on all three axes and set accelerometer range to +/- 8 g
writeByte(MPU6050_ADDRESS, GYRO_CONFIG, 0xE0); // Enable self test on all three axes and set gyro range to +/- 250 degrees/s
delay(250); // Delay a while to let the device execute the self-test
rawData[0] = readByte(MPU6050_ADDRESS, SELF_TEST_X); // X-axis self-test results
rawData[1] = readByte(MPU6050_ADDRESS, SELF_TEST_Y); // Y-axis self-test results
rawData[2] = readByte(MPU6050_ADDRESS, SELF_TEST_Z); // Z-axis self-test results
rawData[3] = readByte(MPU6050_ADDRESS, SELF_TEST_A); // Mixed-axis self-test results
// Extract the acceleration test results first
selfTest[0] = (rawData[0] >> 3) | (rawData[3] & 0x30) >> 4 ; // XA_TEST result is a five-bit unsigned integer
selfTest[1] = (rawData[1] >> 3) | (rawData[3] & 0x0C) >> 4 ; // YA_TEST result is a five-bit unsigned integer
selfTest[2] = (rawData[2] >> 3) | (rawData[3] & 0x03) >> 4 ; // ZA_TEST result is a five-bit unsigned integer
// Extract the gyration test results first
selfTest[3] = rawData[0] & 0x1F ; // XG_TEST result is a five-bit unsigned integer
selfTest[4] = rawData[1] & 0x1F ; // YG_TEST result is a five-bit unsigned integer
selfTest[5] = rawData[2] & 0x1F ; // ZG_TEST result is a five-bit unsigned integer
// Process results to allow final comparison with factory set values
factoryTrim[0] = (4096.0*0.34)*(pow( (0.92/0.34) , (((float)selfTest[0] - 1.0)/30.0))); // FT[Xa] factory trim calculation
factoryTrim[1] = (4096.0*0.34)*(pow( (0.92/0.34) , (((float)selfTest[1] - 1.0)/30.0))); // FT[Ya] factory trim calculation
factoryTrim[2] = (4096.0*0.34)*(pow( (0.92/0.34) , (((float)selfTest[2] - 1.0)/30.0))); // FT[Za] factory trim calculation
factoryTrim[3] = ( 25.0*131.0)*(pow( 1.046 , ((float)selfTest[3] - 1.0) )); // FT[Xg] factory trim calculation
factoryTrim[4] = (-25.0*131.0)*(pow( 1.046 , ((float)selfTest[4] - 1.0) )); // FT[Yg] factory trim calculation
factoryTrim[5] = ( 25.0*131.0)*(pow( 1.046 , ((float)selfTest[5] - 1.0) )); // FT[Zg] factory trim calculation
// Output self-test results and factory trim calculation if desired
// Serial.println(selfTest[0]); Serial.println(selfTest[1]); Serial.println(selfTest[2]);
// Serial.println(selfTest[3]); Serial.println(selfTest[4]); Serial.println(selfTest[5]);
// Serial.println(factoryTrim[0]); Serial.println(factoryTrim[1]); Serial.println(factoryTrim[2]);
// Serial.println(factoryTrim[3]); Serial.println(factoryTrim[4]); Serial.println(factoryTrim[5]);
// Report results as a ratio of (STR - FT)/FT; the change from Factory Trim of the Self-Test Response
// To get to percent, must multiply by 100 and subtract result from 100
for (int i = 0; i < 6; i++) {
destination[i] = 100.0 + 100.0*((float)selfTest[i] - factoryTrim[i])/factoryTrim[i]; // Report percent differences
}
}
void writeByte(uint8_t address, uint8_t subAddress, uint8_t data)
{
Wire.beginTransmission(address); // Initialize the Tx buffer
Wire.write(subAddress); // Put slave register address in Tx buffer
Wire.write(data); // Put data in Tx buffer
Wire.endTransmission(); // Send the Tx buffer
}
uint8_t readByte(uint8_t address, uint8_t subAddress)
{
uint8_t data; // `data` will store the register data
Wire.beginTransmission(address); // Initialize the Tx buffer
Wire.write(subAddress); // Put slave register address in Tx buffer
Wire.endTransmission(false); // Send the Tx buffer, but send a restart to keep connection alive
Wire.requestFrom(address, (uint8_t) 1); // Read one byte from slave register address
data = Wire.read(); // Fill Rx buffer with result
return data; // Return data read from slave register
}
void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t * dest)
{
Wire.beginTransmission(address); // Initialize the Tx buffer
Wire.write(subAddress); // Put slave register address in Tx buffer
Wire.endTransmission(false); // Send the Tx buffer, but send a restart to keep connection alive
uint8_t i = 0;
Wire.requestFrom(address, count); // Read bytes from slave register address
while (Wire.available()) {
dest[i++] = Wire.read(); } // Put read results in the Rx buffer
}
