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Topic: MPU6050 SparkFun Breakout to Arduino Uno - No Communication (Read 27 times) previous topic - next topic

Krodal

#30
Jul 10, 2012, 07:40 pm Last Edit: Jul 10, 2012, 07:42 pm by Krodal Reason: 1
I alread mentioned my sketch : http://arduino.cc/playground/Main/MPU-6050
And it is easier then the Jeff Rowberg code. It doesn't need the interrupt.
On the page there is a link to a i2c_scanner, the device must be visible on the I2C-bus first.
If my sketch is working, you can try the serious code by Jeff Rowberg.

kas

Hi Krodal,

Thanks for your very informative playground article
I bought a GY-52 breakout board which seems rather similar to yours (same manufacturer):



I connected as follow:
VCC - 5V
GND - GND
SCL - A5
SDA - A4

and loaded your code http://arduino.cc/playground/Main/MPU-6050
Amazingly enough, it worked first time

Now, I try to understand why it works  :P  :P
No additional pull up resistors on SDA/SCL
ADO seem to be pulled down (0X68)

Would you mind checking your onboard regulator output, mine is 4.3V with 5V or 3.3V supply
according to datasheet, seems a bit high
Please check the above photo for possible pullup resistors

My final project is a new/better Balancing Robot http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1284738418

Thanks again for this great job

kas

Answering partially my own questions
Not familiar with SMD  :smiley-roll:
The black components with 3 digits are actually resistors (http://www.hobby-hour.com/electronics/3-digit-smd-resistors.php)
331: 330 ohms
103: 10K
472: 4.7K

So, two 10K pull up resistors
Google is definitly your best friend  ;)  ;)

btw, this board can be had for 15 bucks shipped (Google ...)

Krodal

#33
Jul 29, 2012, 11:59 pm Last Edit: Jul 30, 2012, 06:06 am by Krodal Reason: 1

...
Thanks for your very informative playground article
...
Would you mind checking your onboard regulator output, mine is 4.3V with 5V or 3.3V supply
...


I'm glad my sketch did help.

I have a good multimeter. My +5V is 4.95V and the 3.3V of the breakout board is 3.31V.
Also the XDA and XCL of the sub-I2C-bus pins are 3.31V (I think they have a pull-up somewhere).
My MPU-6050 is connected to the I2C via a level shifter, so I have not current flow from the I2C to the MPU-6050 voltage.
Can you measure the SDA and SCL (while not active), and check the XDA and XCL ?

Your breakout board has 10k pull-up resistors to the 3.3V.
That should be 4k7 to be safe.
I think that it might perhaps cause the higher voltage.
Can you add another two pull-up resistors of 10k from the SDA and SCL to the 3.3V of the Arduino board ?

The 4k7 prevents that the internal pull-up resistors in the avr chip (on the Arduino board) raises the voltage of the I2C too high for 3.3V devices.

I have added your GY-52 breakout board : http://arduino.cc/playground/Main/MPU-6050

kas

Thanks,

Rechecked voltage: 3.32V   
go figure  :smiley-roll-blue:   I should add some water in my Bordeaux...

I will put additional resistors on SDA and SCL, on the Arduino side
I guess the original 10K's are OK when more sensors are added to the I2C Bus

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