0
votes

I received a sensor (the accelerometer mpu6050) and I cannot use it. After several tests, I tried to do a basic test with it to see if the I2C Scanner could see it whereas I know that its address is 0x68 or 0x69.

However, I got this message:

Scanning... No I2C devices found

I am using an arduino Nano

Mpu6050 -> Arduino Nano

VCC -> 5V ( but I also tried 3.3V )

GRND -> GRND

SCL -> A5

SDA -> A4

ADO -> GRND

INT -> D2

The code I used ( basic code found several times on the web )

// --------------------------------------
// i2c_scanner
//
// Version 1
//    This program (or code that looks like it)
//    can be found in many places.
//    For example on the Arduino.cc forum.
//    The original author is not know.
// Version 2, Juni 2012, Using Arduino 1.0.1
//     Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26  2013
//    V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
//    by Arduino.cc user Krodal.
//    Changes by louarnold removed.
//    Scanning addresses changed from 0...127 to 1...119,
//    according to the i2c scanner by Nick Gammon
//    http://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
//    As version 4, but address scans now to 127.
//    A sensor seems to use address 120.
// Version 6, November 27, 2015.
//    Added waiting for the Leonardo serial communication.
// 
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
//

#define ADXL_SCL A5
#define ADXL_SDA A4
#include <Wire.h>


void setup()
{
  Wire.begin();
  digitalWrite(ADXL_SDA, LOW);
  digitalWrite(ADXL_SCL, LOW);
  Serial.begin(9600);
  while (!Serial);             // Leonardo: wait for serial monitor
  Serial.println("\nI2C Scanner");
}


void loop()
{
  byte error, address;
  int nDevices;

  Serial.println("Scanning...");

  nDevices = 0;
  for(address = 1; address < 127; address++ ) 
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address<16) 
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");

      nDevices++;
    }
    else if (error==4) 
    {
      Serial.print("Unknown error at address 0x");
      if (address<16) 
        Serial.print("0");
      Serial.println(address,HEX);
    }    
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");

  delay(5000);           // wait 5 seconds for next scan
}

If necessary, here the code I used to try to make the mpu6050 work (also basic code) :

// MPU-6050 Short Example Sketch
// By Arduino User JohnChi
// August 17, 2014
// Public Domain
#include<Wire.h>
const int MPU_addr=0x69;  // I2C address of the MPU-6050
int16_t AcX,AcY,AcZ,Tmp,GyX,GyY,GyZ;
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);
}
void loop(){
  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
  AcX=Wire.read()<<8|Wire.read();  // 0x3B (ACCEL_XOUT_H) & 0x3C (ACCEL_XOUT_L)    
  AcY=Wire.read()<<8|Wire.read();  // 0x3D (ACCEL_YOUT_H) & 0x3E (ACCEL_YOUT_L)
  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.print(AcX);
  Serial.print(" | AcY = "); Serial.print(AcY);
  Serial.print(" | AcZ = "); Serial.print(AcZ);
  Serial.print(" | Tmp = "); Serial.print(Tmp/340.00+36.53);  //equation for temperature in degrees C from datasheet
  Serial.print(" | GyX = "); Serial.print(GyX);
  Serial.print(" | GyY = "); Serial.print(GyY);
  Serial.print(" | GyZ = "); Serial.println(GyZ);
  delay(333);
}

Result :

AcX = -1 | AcY = -1 | AcZ = -1 | Tmp = 36.53 | GyX = -1 | GyY = -1 | GyZ = -1
AcX = -1 | AcY = -1 | AcZ = -1 | Tmp = 36.53 | GyX = -1 | GyY = -1 | GyZ = -1
AcX = -1 | AcY = -1 | AcZ = -1 | Tmp = 36.53 | GyX = -1 | GyY = -1 | GyZ = -1
AcX = -1 | AcY = -1 | AcZ = -1 | Tmp = 36.53 | GyX = -1 | GyY = -1 | GyZ = -1
AcX = -1 | AcY = -1 | AcZ = -1 | Tmp = 36.53 | GyX = -1 | GyY = -1 | GyZ = -1
AcX = -1 | AcY = -1 | AcZ = -1 | Tmp = 36.53 | GyX = -1 | GyY = -1 | GyZ = -1

I would really appreciate your help and feedback because it's really frustrating. I am using well known programs code which work in many tutorials.

Thanks.

2

2 Answers

0
votes

From the official datasheet:

6.4 Electrical Specifications, Continued enter image description here

You connected the AD0 to the ground, thereby changing the address of the device to 0x68 instead of 0x69. Change i2c_addr to 0x68 in your code and all must work as expected.

Also, the datasheet says that the operational voltage for this sensor is 2.375V - 3.46V. I don't know whatever you're using the board with built-in voltage regulator, but if no - putting 5V to this sensor is definitely not a good idea. Probably you already burned your sensor.

0
votes

I see you're not doing Wire.setClock(). I had the same problem with this sensor, and I couldn't get it to work until I added the following in my code, right before Wire.begin():

Wire.setClock(100000);

Try it and see if it works. If not, also try 400000 instead.