Acceleration Measurement with MPU 6050

allison23 · April 7, 2024, 12:33pm

Hello everyone, how are you? Could you help me? I'm conducting acceleration measurements with the MPU 6050 sensor, but I need to use a measurement delay of 1 millisecond for each measurement. However, when I start the measurement with this rate, the Arduino serial freezes after some time of use, around 10 seconds. But when I use the measurement at 40 milliseconds, it works normally, but this measurement doesn't meet my needs, it needs to be 1 millisecond. I'm connecting the Vcc 3.3v to the MPU Vcc on the Arduino, Gnd to Gnd, and SCL and SCA with pull-ups.

What should I do to make this work at the 1 millisecond rate?

// Inclusão das Bibliotecas
#include<Wire.h>
#include<MPU6050.h>
const unsigned long TEMPO = 10;

unsigned long TempoAntes =0, TempoAtual = 0;

// Endereco I2C do sensor MPU-6050
const int MPU = 0x68;

// Variaveis para armazenar valores do sensor
float AccX, AccY, AccZ;
// Variaveis para armazenar o tempo
float TempoDeCorrido = 0;

void setup() {

  // Inicializa Serial
  Serial.begin(115200);
  delay(1000); // Aguarda 1 segundo para garantir que o Arduino está pronto


  // Inicializa o MPU-6050
  Wire.begin();
  Wire.beginTransmission(MPU);
  Wire.write(0x6B);
  Wire.write(0);
  Wire.endTransmission(true);

  // Configura Acelerometro para fundo de escala desejado
  /*
      Wire.write(0b00000000); // fundo de escala em +/-2g
      Wire.write(0b00001000); // fundo de escala em +/-4g
      Wire.write(0b00010000); // fundo de escala em +/-8g
      Wire.write(0b00011000); // fundo de escala em +/-16g
  */
  Wire.beginTransmission(MPU);
  Wire.write(0x1C);
  Wire.write(0b00011000);  // Trocar esse comando para fundo de escala desejado conforme acima
  Wire.endTransmission();

//Apresentação da unidades de medidas
  //Serial.println("Segundos;EixoX;EixoY;EixoZ");
  //Serial.println("s;m/s2;m/s2;m/s2");
  //Serial.println("LABEL,Tempo(s),Eixo X (m/s2),Eixo Y (m/s2),Eixo Z (m/s2)"); // Configura os cabeçalhos das colunas no Excel
}

void loop() {
  TempoAtual = millis();
  if(TempoAtual - TempoAntes >= TEMPO){
  // Comandos para iniciar transmissão de dados
  Wire.beginTransmission(MPU);
  Wire.write(0x3B);// onde começa a receber os dados
  Wire.endTransmission(false);
  Wire.requestFrom(MPU, 6, true); // Solicita os dados ao sensor somente de aceleração

  // Armazena o valor dos sensores nas variaveis correspondentes
  AccX = Wire.read() << 8 | Wire.read();
  AccY = Wire.read() << 8 | Wire.read(); 
  AccZ = Wire.read() << 8 | Wire.read(); 

  // Imprime na Serial os valores obtidos
  /* Alterar divisão conforme fundo de escala escolhido:
      Acelerômetro
      +/-2g = 16384
      +/-4g = 8192
      +/-8g = 4096
      +/-16g = 2048
  */
  // Envia os dados para o Excel usando os comandos do PLX DAQ v2
  //Serial.print("DATA,"); // Comando para enviar dados para o Excel
  ///Serial.print(TempoDeCorrido);
  //Serial.print(","); // Separador de colunas
 //Serial.println((AccX / 2048) * 9.81);// Aceleração X em m/s^2
 // Serial.print(" "); // Separador de colunas
 // Serial.print((AccY / 2048) * 9.81);// Aceleração Y em m/s^2
  //Serial.print(" "); // Separador de colunas
  Serial.println((AccZ / 2048.0) * 9.81);// Aceleração Y em m/s^2

  TempoDeCorrido += 0.1; // Incrementa o tempo
  TempoAntes = TempoAtual;
}
}

PaulRB · April 7, 2024, 12:39pm

Make this faster.

But I'm not sure you will get to 1ms that way.

PaulRB · April 7, 2024, 12:42pm

You can get a little more speed with

Wire.begin(400000);

allison23 · April 7, 2024, 12:50pm

I changed the clock, but it still didn't work.

allison23 · April 7, 2024, 12:51pm

I did some tests with the multimeter and when I measure one of the SCL or SCA ports, the data starts working again when the system is frozen. What could it be?

jremington · April 7, 2024, 1:07pm

Use a pushbutton on a digital pin to start and stop measurements, at any time after program upload.

When you upload a program, the Arduino is automatically rebooted, which leads to a delay in startup. There there is this, which takes some time.

// Inicializa Serial
  Serial.begin(115200);
  delay(1000); // Aguarda 1 segundo para garantir que o Arduino está pronto

allison23 · April 7, 2024, 1:28pm

I don't have a button right now, but I can implement sending information through serial to start the countdown as shown below.
Will it work the same?

// Inicializa Serial
  Serial.begin(2000000);
  while(!Serial.available());
  Serial.read();

jremington · April 7, 2024, 1:29pm

Try it and see.

allison23 · April 7, 2024, 1:40pm

It didn't work.

jremington · April 7, 2024, 1:53pm

Have a look at the Serial Input Basics tutorial, and use those ideas to wait for a certain keyboard character to be pressed, to start or stop the measurement.

PaulRB · April 7, 2024, 3:25pm

This works:

16:22:27.540 -> 9.55
16:22:27.540 -> 9.57
16:22:27.540 -> 9.41
...
16:22:27.948 -> 9.50
16:22:27.948 -> 9.49
16:22:27.948 -> 9.47
16:22:27.948 -> Readings: 1000 Time:1000ms

Code:

// Inclusão das Bibliotecas
#include<Wire.h>
//#include<MPU6050.h>
const unsigned long TEMPO = 1000;

unsigned long TempoAntes = 0, TempoAtual = 0;

// Endereco I2C do sensor MPU-6050
const int MPU = 0x68;

// Variaveis para armazenar valores do sensor
float AccX, AccY, AccZ;
// Variaveis para armazenar o tempo
float TempoDeCorrido = 0;

void setup() {

  // Inicializa Serial
  Serial.begin(115200);
  delay(1000); // Aguarda 1 segundo para garantir que o Arduino está pronto


  // Inicializa o MPU-6050
  Wire.begin();
  Wire.setClock(400000);
  Wire.beginTransmission(MPU);
  Wire.write(0x6B);
  Wire.write(0);
  Wire.endTransmission(true);

  // Configura Acelerometro para fundo de escala desejado
  /*
      Wire.write(0b00000000); // fundo de escala em +/-2g
      Wire.write(0b00001000); // fundo de escala em +/-4g
      Wire.write(0b00010000); // fundo de escala em +/-8g
      Wire.write(0b00011000); // fundo de escala em +/-16g
  */
  Wire.beginTransmission(MPU);
  Wire.write(0x1C);
  Wire.write(0b00011000);  // Trocar esse comando para fundo de escala desejado conforme acima
  Wire.endTransmission();

  //Apresentação da unidades de medidas
  //Serial.println("Segundos;EixoX;EixoY;EixoZ");
  //Serial.println("s;m/s2;m/s2;m/s2");
  //Serial.println("LABEL,Tempo(s),Eixo X (m/s2),Eixo Y (m/s2),Eixo Z (m/s2)"); // Configura os cabeçalhos das colunas no Excel
}

void loop() {
  static int count = 0;
  static unsigned long prevTime;
  TempoAtual = micros();
  if (TempoAtual - TempoAntes >= TEMPO) {
    // Comandos para iniciar transmissão de dados
    Wire.beginTransmission(MPU);
    Wire.write(0x3B);// onde começa a receber os dados
    Wire.endTransmission(false);
    Wire.requestFrom(MPU, 6, true); // Solicita os dados ao sensor somente de aceleração

    // Armazena o valor dos sensores nas variaveis correspondentes
    AccX = Wire.read() << 8 | Wire.read();
    AccY = Wire.read() << 8 | Wire.read();
    AccZ = Wire.read() << 8 | Wire.read();

    // Imprime na Serial os valores obtidos
    /* Alterar divisão conforme fundo de escala escolhido:
        Acelerômetro
        +/-2g = 16384
        +/-4g = 8192
        +/-8g = 4096
        +/-16g = 2048
    */
    // Envia os dados para o Excel usando os comandos do PLX DAQ v2
    //Serial.print("DATA,"); // Comando para enviar dados para o Excel
    ///Serial.print(TempoDeCorrido);
    //Serial.print(","); // Separador de colunas
    //Serial.println((AccX / 2048) * 9.81);// Aceleração X em m/s^2
    // Serial.print(" "); // Separador de colunas
    // Serial.print((AccY / 2048) * 9.81);// Aceleração Y em m/s^2
    //Serial.print(" "); // Separador de colunas
    Serial.println((AccZ / 2048.0) * 9.81);// Aceleração Y em m/s^2
    count++;

    TempoDeCorrido += 0.1; // Incrementa o tempo
    TempoAntes = TempoAtual;
  }
  if (count >= 1000) {
    unsigned long timeNow = millis();
    Serial.print("Readings: ");
    Serial.print(count);
    Serial.print(" Time:");
    Serial.print(timeNow - prevTime);
    Serial.println("ms");
    delay(1000);
    prevTime = millis();
    count = 0;
  }
}

allison23 · April 7, 2024, 5:11pm

I think the MPU 6050 sensor I have is defective or faulty because my ADXL 345 works normally using the same logic I used with the MPU 6050. Thanks to everyone who helped me, I will purchase another MPU 6050 from a more reliable seller.

PaulRB · April 7, 2024, 5:42pm

Did you try my code with your MPU6050?

allison23 · April 7, 2024, 6:01pm

Yes, the sensor stopped performing measurements in the same way.

PaulRB · April 7, 2024, 6:03pm

Ok, that's not good.

What output do you see before it stops?

jremington · April 7, 2024, 7:40pm

The MPU-6050 was discontinued years ago, and all you can buy today are clones or fakes. The ISM330DHCX is much, much better in every respect.

system · October 4, 2024, 7:40pm

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Acceleration Measurement with MPU 6050

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