by Sjef on Thu Nov 15, 2012 6:47 pm


I have an Arduino and an Adafruit data logger shield.
I want to log the data from this IMU sensor:

The sensor has to be connected to the 5v power supply on the Arduino board and the i2c lines are operating at 3.3v.
The i2c lines from the RTC on the data logger shield are operating at 5v because of the pull up resistors R1 and R2 in this schematics:

Because the sensor already has internal pull up resistors, I removed the R1 and R2 pull up resistors of the shield.

When I connect the logger and the sensor to the Arduino, they aren't working correctly.
Both the logger shield and the sensor are working nice when I connect them separately.
Maybe the problem is that the shield also uses the 5v power supply on the Arduino.

I don't fully understand the schematics of the shield, but it seems the shield is using the 5v power supply from the Arduino.

Is this true?
If not, what am I doing wrong?

Thanks in advance!
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by adafruit_support_bill on Fri Nov 16, 2012 5:46 am

The shield does use +5v, but there should be no problem sharing it with the IMU.

It is possible you have an i2c address conflict. The DS1307 is at 0x68. Check the address of your IMU.
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by Sjef on Sun Dec 09, 2012 4:20 pm

Thanks for your reply! It didn't work because the RTC and the IMU had the same i2c address, so this topic can be closed.
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