Connecting the GY-521 Gyroscope

Hi. I’ve been trying to get my GY-521 gyroscope connected to my Arduino UNO R3 this past week and unfortunately I had no luck. Currently I am hooking up the ports as follows:

Vcc - 3.3V
GND - GND
SCL - D5
SDA - D4
ADO - GND
INT - D2

Here is the code I am using

// I2C device class (I2Cdev) demonstration Arduino sketch for MPU6050 class
// 10/7/2011 by Jeff Rowberg <jeff@rowberg.net>
// Updates should (hopefully) always be available at https://github.com/jrowberg/i2cdevlib
//
// Changelog:
//     2011-10-07 - initial release
 
/* ============================================
I2Cdev device library code is placed under the MIT license
Copyright (c) 2011 Jeff Rowberg
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
===============================================*/
 
// Arduino Wire library is required if I2Cdev I2CDEV_ARDUINO_WIRE implementation
// is used in I2Cdev.h
#include "Wire.h"
 
// I2Cdev and MPU6050 must be installed as libraries, or else the .cpp/.h files
// for both classes must be in the include path of your project
#include "I2Cdev.h"
#include "MPU6050.h"
 
// class default I2C address is 0x68
// specific I2C addresses may be passed as a parameter here
// AD0 low = 0x68 (default for InvenSense evaluation board)
// AD0 high = 0x69
MPU6050 accelgyro;
 
int16_t ax, ay, az;
int16_t gx, gy, gz;
 
#define LED_PIN 13
bool blinkState = false;
 
// accelerometer values
int accel_reading;
int accel_corrected;
int accel_offset = 200;
float accel_angle;
float accel_scale = 1; // set to 0.01
 
// gyro values
int gyro_offset = 151; // 151
int gyro_corrected;
int gyro_reading;
float gyro_rate;
float gyro_scale = 0.02; // 0.02 by default - tweak as required
float gyro_angle;
float loop_time = 0.05; // 50ms loop
float angle = 0.00; // value to hold final calculated gyro angle
 
// time stamp variables
int last_update;
int cycle_time;
long last_cycle = 0;
 
void setup() {
  // join I2C bus (I2Cdev library doesn't do this automatically)
Wire.begin();
 
// initialize serial communication
Serial.begin(9600);
 
// initialize device
Serial.println("Initializing I2C devices...");
accelgyro.initialize();
 
// verify connection
Serial.println("Testing device connections...");
Serial.println(accelgyro.testConnection() ? "MPU6050 connection successful" : "MPU6050 connection failed");
 
// configure Arduino LED for
pinMode(LED_PIN, OUTPUT);
}
 
void loop(){
  // read raw accel/gyro measurements from device
  accelgyro.getMotion6(&ax, &ay, &az, &gx, &gy, &gz);
 
  // accelerometer_X_Axis angle calc
  accel_reading = ax;
  accel_corrected = accel_reading - accel_offset;
  accel_corrected = map(accel_corrected, -16800, 16800, -90, 90);
  accel_corrected = constrain(accel_corrected, -90, 90);
  accel_angle = (float)(accel_corrected * accel_scale);
  Serial.print(accel_angle);
  Serial.print("\t");
   
  // gyro_Y_Axis angle calc  
  gyro_reading = gy;
  gyro_corrected = (float)((gyro_reading/131) - gyro_offset);  // 131 is sensivity of gyro from data sheet
  gyro_rate = (gyro_corrected * gyro_scale) * -loop_time;      // loop_time = 0.05 ie 50ms        
  gyro_angle = angle + gyro_rate;
  
  // print values to serial monitor for checking 
  Serial.print(gyro_reading);
  Serial.print("\t");
  Serial.print(gyro_corrected);
  Serial.print("\t");
  Serial.print(gyro_angle);
  Serial.print("\t");
  Serial.println(" ");
    
  // blink LED to indicate activity
  blinkState = !blinkState;
  digitalWrite(LED_PIN, blinkState);
  
//timestamp
time_stamp();
}
void time_stamp(){
  while ((millis() - last_cycle) < 50){
  delay(1);
  }
  // once loop cycle reaches 50ms, reset timer value and continue
  cycle_time = millis() - last_cycle;
  last_cycle = millis();
}

I got the code from Gyro angle calc code · GitHub

Currently, all that I am getting is the following :

­Initializing I2C devices…
Testing device connections…
MPU6050 connection failed
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *

Can someone please help me?

(deleted)

Yes. I have a pull up connected to both scl and sda line. I just wanted to correct my first post. I am not getting 0. I am getting the following from the serial monitor.

­Initializing I2C devices...
Testing device connections...
MPU6050 connection failed
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *

Below is a link with a picture of my connections

(deleted)

Ok. I switched digital ports 4 and 5 to analog. The port switch is definitely a move in the right direction but It is still not working. The serial monitor is now only outputting:

Initializing I2C devices...

What I have noticed is that if you unplug the A5 and A4 ports after Initializing I2C devices... pops up, the serial monitor will continue outputting the following:

Testing device connections...
MPU6050 connection failed
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *
*-2.00 0 -151 0.15 *

Below is a updated link with a picture of my connections

File sharing and storage made simpleCopy(2).jpg

Look for the sketch I2Cscanner, and run that. You can see from that, whether the I2C interface of your sensor device can be detected from the arduino, which would indicate that your I2C device is properly connected. It will also confirm that you are using the correct I2C device address in your sketch.

I ran the i2c_scanner. The serial monitor prints the following lines and then freezes.

I2C Scanner
Scanning...

I noticed that the same thing happens as before. If I remove both analog pins, the program resumes back to normal.

There is probably something wrong with your connection. Are your pull-up resistors connected properly ? In your photo, it seems to be connected to ground.

The other thing you should check is the power supply.

Many of these devices have two power inputs. There is an input for 5V which connects to a regulator on the module and supplies 3.3V to the chips on the module. And then there is an input for 3.3V which supplies voltage directly to the chips on the module.

If you connect a 3.3V supply to the input which is going into the regulator, then it won't work.

Here's a diagram which shows the power supply:

https://www.google.com.au/search?q=gy-521&tbm=isch&imgil=t7fapXRkaslyvM%3A%3Bhttps%3A%2F%2Fencrypted-tbn2.gstatic.com%2Fimages%3Fq%3Dtbn%3AANd9GcQsY3npa4sTHQCGLvrLEud_w83ULHOP5No508vGtGUrZEJ1J111%3B1026%3B601%3BJO2U4b_z0iPc3M%3Bhttp%253A%252F%252Felectronics.stackexchange.com%252Fquestions%252F61286%252Fwiring-a-gy-521-to-an-arduino-uno-r3&source=iu&usg=__aUwigUDFUXogcgNufejoXJN8Ebw%3D&sa=X&ei=MO72UvWiAsfEkgW7h4DQBA&sqi=2&ved=0CEcQ9QEwAg&biw=1138&bih=493#facrc=_&imgrc=t7fapXRkaslyvM%3A%3BJO2U4b_z0iPc3M%3Bhttp%3A%2F%2Fi.stack.imgur.com%2Fd8ilO.jpg%3Bhttp%3A%2F%2Felectronics.stackexchange.com%2Fquestions%2F61286%2Fwiring-a-gy-521-to-an-arduino-uno-r3%3B1026%3B601

If that diagram is correct, there may be pull-up resistors already on the module.

I just gave myself the biggest facepalm in the world. Turns out that it was my fault it did not work. One of the holes on the gyro was not touching the metal pin on the breadboard. I want to apologize for putting you guys trough this mess.