Originally Posted by Ascended
* Check that the BMP085's I2C lines are 5V tolerant.
Technically they can work with 5v signaling, but it will burn out if it gets 5v from the Atmega's internal pullups. Of course those can be turned off, but I would add a level shifter, either resistor dividers or something cheap like a PCA9306.
Its a really good looking board, good work.