Help with GY-521 with Nano 3.0

Using Arduino Sensors
1

Currently, I have the Arduino Nano 3.0 wired to the GY-521 as follows:
Nano/GY-521
3.3V/VCC
GND/GND
A5/SCL
A4/SDA

After downloading and placing the appropriate libraries into the Arduino folder I was able to compile the sample code on the website fine (Arduino Playground - MPU-6050). Problem is that I am getting the following readings while it is staying still on my table, and even while I move everything.

InvenSense MPU-6050
June 2012
WHO_AM_I : 11, error = 2
PWR_MGMT_2 : 11, error = 2

MPU-6050
Read accel, temp and gyro, error = 2
accel x,y,z: -5374, 2, 305
temperature: 37.212 degrees Celsius
gyro x,y,z : 2050, -13039, -29695, 

MPU-6050
Read accel, temp and gyro, error = 2
accel x,y,z: 747, 512, 12545
temperature: 24.459 degrees Celsius
gyro x,y,z : 520, 4557, 396, 

MPU-6050
Read accel, temp and gyro, error = 2
accel x,y,z: -5374, 2, 305
temperature: 37.212 degrees Celsius
gyro x,y,z : 2050, -13039, -29695, 

MPU-6050
Read accel, temp and gyro, error = 2
accel x,y,z: 747, 512, 12545
temperature: 24.459 degrees Celsius
gyro x,y,z : 520, 4557, 396, 

MPU-6050
Read accel, temp and gyro, error = 2
accel x,y,z: -5374, 2, 305
temperature: 37.212 degrees Celsius
gyro x,y,z : 2050, -13039, -29695, 

MPU-6050
Read accel, temp and gyro, error = 2
accel x,y,z: 747, 512, 12545
temperature: 24.459 degrees Celsius
gyro x,y,z : 520, 4557, 396,

What have I done wrong to get these readings?

2

You have an error returned, so you are not communicating with the chip.
Start with the i2c scanner, Arduino Playground - HomePage

3

I did this already and it says that there isn't a device found. Thing is that I connected it according to how the others on the forum had the GY connected to their Arduino.

4

You need to make sure you are using the correct connection for I2C. Have you got any other I2C device
that you can use, to check your Arduino will do I2C correctly ?

5

There are only three components in the project that I am using: Arduino, GY521, and the RN42 (Bluetooth transmitter). The RN42 uses the digital pins not analog. Other than the two mentioned I don't have anything at the moment.

6

At the moment, the LED on the GY is lit giving me some hope that it is not defective.

7

well first, you need to be able to detect it on the I2C connection. So you need to run that scanner program and check everything
until the device responds.

8

After thinking about it I connected the RN42 and ran the program and it didn't pick up, yet I know it works since I have been able to use my test program. It does use the digital pins though, so does that mean that the program only scans analog?

I also rotated the connections from the GY to all the analog pins from A0-A7 and nothing seemed to recognize. What I am wondering after reading some other posts is if I am not supposed to connect the module directly into the Arduino and that the GY has to go through a resistor before being used with the Arduino is that right. If so what should I have to connect it with?

9

The GY-521 does have a voltage regulator on the board.
So normally connect the 5V of the Arduino to the Vcc of the GY-521. The GY-521 makes 3.3V for the sensor.

There is nothing analog on the GY-521.
Pin A4 and A5 are analog pins on the Arduino, but they can do more. They can also be used as digital pins, and they can be used for the digital I2C bus.
As soon as the sketch uses Wire.begin(), those pins will be the I2C bus and are no longer analog pins.

Could you try once more:
Arduino GND to GY-521 GND
5V to Vcc
A4 to SDA
A5 to SCL
Can you make a photo of it, and upload it? So we can take a look ?

If the i2c scanner still is not recognizing anything, something else must be wrong. Perhaps somehting is broken or a bad connection. Do you use a breadboard ?

10

I am using a breadboard, and it is fairly over a year old. In relation to uploading pictures, I couldn't figure it out (new to forums = inexperienced).

11

Breadboards cause many problems with bad connections. You could try an other location of the breadboard.
If you write a message, click "Additional Options" below the text field and you can "Attach" a file.

12

I am actually at work at the moment, but here is the picture that I tried to attach yesterday. Hope you can see everything clearly.

2013-03-11_16-54-23_754.jpg
2013-03-11_16-54-23_754.jpg1840×3264 1.27 MB

13

You don't have a Arduino Nano.
You have a funduino clone with a fake www.funduino.com website.
The analog pins are in a different order than the real Arduino Nano.

These fake ones are sold by DealExtreme as real Arduino nano, and they ask 17.80 dollars.
The same fake at Ebay is 11.50 dollars.

On the photo, you use the 3V3 pin, can you try the 5V pin for the Vcc ?
It seems that A3 and A4 are used, but you need A4 and A5.

14

I can try connecting the 5v to the GY, but the reason I used 3.3v was that it is the max voltage for the RN42. Also, SCL & SDA leads are on A3 & A4 since I tried your advice and tried them on the other pins. This picture shows where I left it last.

I'll reply back how it goes, and if the GY works or not.

15

It's alive! It's alive! (but finicky)

After wiring up correctly with the 5v the GY was able to be detected with the I2Scanner program, but for some reason it's still giving me some sporadic values when it is just sitting there. I am quite certain that majority of the readings should be at least close to each other while the accelerometer zeros out.

I have attached some of the readings.

MPU-6050 Bad readings.docx (13.2 KB)

16

Good to know it is alive.

If the returned error is 0, everything is okay. The values are the raw values of the sensor. And yes, they look all over the place, but they are good.

The chip has a dmp for filtering, or you could use kalman filtering.
Jeff Rowberg his libraries uses the dmp. It is part of the i2cdev, http://www.i2cdevlib.com/

17

For some reason I can't figure out the commands of how to operate it. I reduced the baud rate to 9600 for the Arduino to use, but for some reason when I put in something it just returns gibberish. Where are the key commands to operate the program?

18

The MPU-6050 is a complex sensor, and so is the software by Jeff Rowberg.
You have to tell me more: Which program ? Did you use an example sketch ? Which one ? Did you read the sketch what it does ? Did you read this page Arduino Playground - MPU-6050 ? Did you connect the INT signal for Jeff Rowberg's code ?

19

I was using the sketch named: MPU6050_DMP6 from github folder. The playground website I have read more times than I can count, but from what I have read it doesn't point to anything else than Jeff's website that I am already using for filter the results. The main problem is that in his code, or documentation, there isn't a clear way of how to filter the readings or the commands of how to properly use the program that I am mentioned.

20

It is a lot of code, but this is the documentation page: I2Cdevlib: MPU6050 Class Reference
Search for "dlpf" and "dhpf". I think those are the filters to filter the raw data inside the sensor chip.
They can be set, even if the dmp is used.

For the dmp itself, the function "dmpSetLinearAccelFilterCoefficient()" seems not to have been implemented yet.