I am learning how to integrate sensors on arduinos and read their data.
My ultimate purpose is to place the IMU on a robot and use it in determining the robots location in an environment.
Using the following code, I am able to get accelerometer and temperature data:
// (c) Michael Schoeffler 2017, http://www.mschoeffler.de
#include "Wire.h" // This library allows you to communicate with I2C devices.
const int MPU_ADDR = 0x68; // I2C address of the MPU-6050. If AD0 pin is set to HIGH, the I2C address will be 0x69.
int16_t accelerometer_x, accelerometer_y, accelerometer_z; // variables for accelerometer raw data
int16_t gyro_x, gyro_y, gyro_z; // variables for gyro raw data
int16_t temperature; // variables for temperature data
char tmp_str[7]; // temporary variable used in convert function
char* convert_int16_to_str(int16_t i) { // converts int16 to string. Moreover, resulting strings will have the same length in the debug monitor.
sprintf(tmp_str, "%6d", i);
return tmp_str;
}
void setup() {
Serial.begin(9600);
Wire.begin();
Wire.beginTransmission(MPU_ADDR); // Begins a transmission to the I2C slave (GY-521 board)
Wire.write(0x6B); // PWR_MGMT_1 register
Wire.write(0); // set to zero (wakes up the MPU-6050)
Wire.endTransmission(true);
}
void loop() {
Wire.beginTransmission(MPU_ADDR);
Wire.write(0x3B); // starting with register 0x3B (ACCEL_XOUT_H) [MPU-6000 and MPU-6050 Register Map and Descriptions Revision 4.2, p.40]
Wire.endTransmission(false); // the parameter indicates that the Arduino will send a restart. As a result, the connection is kept active.
Wire.requestFrom(MPU_ADDR, 7*2, true); // request a total of 7*2=14 registers
// "Wire.read()<<8 | Wire.read();" means two registers are read and stored in the same variable
accelerometer_x = Wire.read()<<8 | Wire.read(); // reading registers: 0x3B (ACCEL_XOUT_H) and 0x3C (ACCEL_XOUT_L)
accelerometer_y = Wire.read()<<8 | Wire.read(); // reading registers: 0x3D (ACCEL_YOUT_H) and 0x3E (ACCEL_YOUT_L)
accelerometer_z = Wire.read()<<8 | Wire.read(); // reading registers: 0x3F (ACCEL_ZOUT_H) and 0x40 (ACCEL_ZOUT_L)
temperature = Wire.read()<<8 | Wire.read(); // reading registers: 0x41 (TEMP_OUT_H) and 0x42 (TEMP_OUT_L)
// gyro_x = Wire.read()<<8 | Wire.read(); // reading registers: 0x43 (GYRO_XOUT_H) and 0x44 (GYRO_XOUT_L)
// gyro_y = Wire.read()<<8 | Wire.read(); // reading registers: 0x45 (GYRO_YOUT_H) and 0x46 (GYRO_YOUT_L)
// gyro_z = Wire.read()<<8 | Wire.read(); // reading registers: 0x47 (GYRO_ZOUT_H) and 0x48 (GYRO_ZOUT_L)
// // print out data
Serial.print("aX = "); Serial.print(convert_int16_to_str(accelerometer_x));
Serial.print(" | aY = "); Serial.print(convert_int16_to_str(accelerometer_y));
Serial.print(" | aZ = "); Serial.print(convert_int16_to_str(accelerometer_z));
// // the following equation was taken from the documentation [MPU-6000/MPU-6050 Register Map and Description, p.30]
Serial.print(" | tmp = "); Serial.print(temperature/340.00+36.53);
// Serial.print(" | gX = "); Serial.print(convert_int16_to_str(gyro_x));
// Serial.print(" | gY = "); Serial.print(convert_int16_to_str(gyro_y));
// Serial.print(" | gZ = "); Serial.print(convert_int16_to_str(gyro_z));
Serial.println();
// delay
delay(1000);
}
Giving me output like the following:
aX = 3526 | aY = -968 | aZ = -11988 | tmp = 25.89
aX = 3478 | aY = -936 | aZ = -12020 | tmp = 25.91
aX = 3530 | aY = -922 | aZ = -12002 | tmp = 25.91
aX = 3490 | aY = -896 | aZ = -12006 | tmp = 25.94
aX = 3498 | aY = -898 | aZ = -12036 | tmp = 25.91
aX = 3520 | aY = -916 | aZ = -12050 | tmp = 25.91
aX = 3466 | aY = -924 | aZ = -11960 | tmp = 25.91
aX = 3492 | aY = -944 | aZ = -12026 | tmp = 25.92
aX = 3510 | aY = -924 | aZ = -12048 | tmp = 25.91
aX = 3440 | aY = -942 | aZ = -11980 | tmp = 25.91
aX = 3514 | aY = -924 | aZ = -12066 | tmp = 25.91
aX = 3484 | aY = -944 | aZ = -11968 | tmp = 25.92
aX = 3490 | aY = -944 | aZ = -12012 | tmp = 25.92
aX = 3458 | aY = -952 | aZ = -11944 | tmp = 25.92
What I need to know is how do I determine what direction my robot is moving in based on the accelerometer output?
