The BeagleBoard xM comes equipped with 3 I2C buses which can be used with I2C devices. Our ranging sensors have an analog output between 0 and +5 Volts. Because we have 6 of these sensors we are using an 8 channel A/D converter that communicates over I2C.
The ADC board uses 5V logic while the BeagleBoard uses 1.8V logic. The ADC board will be connected to the BeagleBoard via a logic level converter. We spent some time finding the pinout for the SDA and SDL pins on the board. The manuals have not been updated for our revision so the header is labeled improperly, but we were able to find the pin position on the board. Next week we plan to connect the I2C output bus to Nelson’s logic analyzer and run tests to ensure we can communicate properly with the I2C bus.
The afternoon we assembled the quadrocopter platform. The assembly went smoothly until the end when we discovered we were missing a piece which mounts the flight controller. This is annoying, but we have already come up with a few ways to mount the controller without this backing panel. A timelapse of the build can be watched on Youtube here: