I2C sensors and mega2560

Development Boards Arduino
1

I’m missing something here, I have 3 sensors that are the I2C format. I haven’t gotten one of them to work.

I’m using the 3.3 volt lead on the ardunio so I’m not over volting the sensors.

I have these sensors.

BMP085 (barometric and temp)

HMC6843 (magnetometer)

ITG-3200 (3axis gyro)

I saw in the comments the issues with the magnetometer and a capacitor but the breakout board I have doesn’t have the guilty component.

I guess my question is has anyone got the mega to work with the I2C sensors?

Also I am using A4 and A5 pins on the arduino as the how-to’s have listed. Is this correct on the mega? Is there a way to change the pins in the code I haven’t traced the wire library, but didn’t see where the pins were set in the sample code.

Thanks, so far I’ve gotten the parts I’ve ordered from hacktronics working but haven’t had much luck with the sparkfun pieces.

A side question what temp to you recommend soldering the headers on the break out boards? I have a digital 50w weller soldering iron and I don’t want to over heat them.

2

Found the solution on the mega 2560 you have to use the pins 20 (SDA) and 21 (SCL) for I2C sensors. Not very well documented but finally after looking through the spec sheets for the 2560 it dawned on me that since the board has SDA and SCL printed on these pins to give it a try.

Hope this helps someone save some time. I guess I should of worked my way up to this level instead of jumping into a large project all at once.