Dear all,
I'm trying to measure vibrations of the motor's shaft that is oscillating due to an eccentric load. For that, I am using the MPU 6050 6 axis accelerometer. The motor is a NEMA 17 stepper, connected to Arduino UNO via the EasyDriver v4.4.
I first uploaded my code for the stepper, where I have 2 buttons to control the rotation direction (if you press the left, it goes clockwise and if you press the right button it goes counter clockwise). This code works fine.
Later I uploaded the code only for the accelerometer and it worked fine, however when I'm trying to combine both so that the vibrations could be measured while the motor is running, apparently I'm losing steps of the motor. Here is the code:
#include<Wire.h>
const int MPU_addr = 0x68; // I2C address of the MPU-6050
int16_t AcX, AcY, AcZ, Tmp, GyX, GyY, GyZ;
#define RPMS 300.0
#define STEP_PIN 9
#define DIRECTION_PIN 8
#define GO_PIN_L 3
#define GO_PIN_R 4
#define STEPS_PER_REV 200
#define MICROSTEPS_PER_STEP 8
#define MICROSECONDS_PER_MICROSTEP (1000000/(STEPS_PER_REV * MICROSTEPS_PER_STEP)/(RPMS / 60))
uint32_t LastStepTime = 0;
uint32_t CurrentTime = 0;
int Distance = 0;
void setup() {
Wire.begin();
Wire.beginTransmission(MPU_addr);
Wire.write(0x6B); // PWR_MGMT_1 register
Wire.write(0); // set to zero (wakes up the MPU-6050)
Wire.endTransmission(true);
Serial.begin(9600);
pinMode(STEP_PIN, OUTPUT);
pinMode(DIRECTION_PIN, OUTPUT);
digitalWrite(STEP_PIN, LOW);
digitalWrite(DIRECTION_PIN, LOW);
pinMode(GO_PIN_L, INPUT);
pinMode(GO_PIN_R, INPUT);
}
void loop() {
Distance = Distance + 1; // record this step
if (digitalRead(GO_PIN_L) == LOW)
{
CurrentTime = micros();
digitalWrite(8, LOW);
if ((CurrentTime - LastStepTime) > MICROSECONDS_PER_MICROSTEP)
{
LastStepTime = CurrentTime;
digitalWrite(STEP_PIN, HIGH);
delayMicroseconds((MICROSECONDS_PER_MICROSTEP * 0.9) / 2);
digitalWrite(STEP_PIN, LOW);
delayMicroseconds((MICROSECONDS_PER_MICROSTEP * 0.9) / 2);
}
}
if (digitalRead(GO_PIN_R) == LOW)
{
CurrentTime = micros();
digitalWrite(8, HIGH);
if ((CurrentTime - LastStepTime) > MICROSECONDS_PER_MICROSTEP)
{
LastStepTime = CurrentTime;
digitalWrite(STEP_PIN, HIGH);
delayMicroseconds((MICROSECONDS_PER_MICROSTEP * 0.9) / 2);
digitalWrite(STEP_PIN, LOW);
delayMicroseconds((MICROSECONDS_PER_MICROSTEP * 0.9) / 2);
}
}
// Wire.beginTransmission(MPU_addr);
// Wire.write(0x3B); // starting with register 0x3B (ACCEL_XOUT_H)
// Wire.endTransmission(false);
// Wire.requestFrom(MPU_addr, 14, true); // request a total of 14 registers
// float AcX = Wire.read() << 8 | Wire.read(); // 0x3B (ACCEL_XOUT_H) & 0x3C (ACCEL_XOUT_L)
// float AcY = Wire.read() << 8 | Wire.read(); // 0x3D (ACCEL_YOUT_H) & 0x3E (ACCEL_YOUT_L)
// float AcZ = Wire.read() << 8 | Wire.read(); // 0x3F (ACCEL_ZOUT_H) & 0x40 (ACCEL_ZOUT_L)
// Tmp = Wire.read() << 8 | Wire.read(); // 0x41 (TEMP_OUT_H) & 0x42 (TEMP_OUT_L)
// // GyX=Wire.read()<<8|Wire.read(); // 0x43 (GYRO_XOUT_H) & 0x44 (GYRO_XOUT_L)
// // GyY=Wire.read()<<8|Wire.read(); // 0x45 (GYRO_YOUT_H) & 0x46 (GYRO_YOUT_L)
// // GyZ=Wire.read()<<8|Wire.read(); // 0x47 (GYRO_ZOUT_H) & 0x48 (GYRO_ZOUT_L)
// Serial.print("AcX = "); Serial.println(AcX / 16384);
// Serial.print(" AcY = "); Serial.println(AcY / 16384);
// Serial.print(" AcZ = "); Serial.println(AcZ / 16384);
// Serial.print(" Tmp = "); Serial.print(Tmp / 340.00 + 36.53);
// Serial.println("");
// // Serial.print(" | GyX = "); Serial.print(GyX);
// // Serial.print(" | GyY = "); Serial.print(GyY);
// // Serial.print(" | GyZ = "); Serial.println(GyZ);
// delay(333);
}
So the commented portion of the code is used to read and print accelerations. Since this is in the same loop as the code for the motor, I'm sure that the delay(333) has a negative effect, but also when I tried step-by-step to include lines of code for accelerometer, the motor slowly starter to losing speed and steps...
Does anyone of you have a clue how this could be done so that both devices (the motor with EasyDriver v 4.4 and the accelerometer) could run simultaneously?
Kind regards,
Luka