MU Hardware

http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/APM-IMU.png

The two expansion ports go to ATmega1280 pins PF6 and PF7. That's Analog 5 and 6 in Arduino.

Features

• Dual 3.3V Regulator. (One dedicated for analog sensors)
• Relay switch for cameras, lights or payloads
• 12-bit ADC for better Gyro/Accel/!AirSpeed resolution.
• Built-in 16Mb Data Logger (The Black Box).
• Piano DIP switch for servo reverse or user customizable.
• Built-in FTDI, making the board native USB.
• Dedicated Modem/OSD port.
• I2C Port with incoming "Daisy Chain board" allowing you to build sensor arrays.
• Two user-programmable buttons (one momentary, the other slide).
• 10-Bit analog expansion ports.
• Reset button.
• Optional "Through Hole" voltage dividers (Easy to solder).
• Tons of Status LEDs.
• New vibration resistance Invensense Gyros (Triple Axis).
• Analog Devices ADX330 Accelerometer.
• Airspeed sensor port (optional, sold separately).
• Absolute Bosch pressure sensor and temp for accurate altitude (Yes, you can use your shield as a Weather Logger, too).

PCB files

IMU shield Eagle files:

• Schematic
• Board

IMU shield pdf files:

• Schematic
• Board

Pin Mappings

A spreadsheet showing all the pin mappings and functions is here