arduino_firmware.txt

Making Arduino firmware:

1. install Arduino IDE
http://arduino.cc/en/Main/Software
(tested on 1.0.3, 1.0.4)

2. connect Arduino board and select Serial port and Arduino version
(Arduino Nano w/ ATmega 328)

2. install 3rdparty libraries:
* TimerOne 
(tested v9)
https://code.google.com/p/arduino-timerone/downloads/list

* ultrasonic-HC-SR04
http://robocraft.ru/files/sensors/Ultrasonic/HC-SR04/ultrasonic-HC-SR04.zip

3. in Arduino sketchbook folder create directory with name:
robot_4wd_firmware

4. into robot_4wd_firmware folder copy source files:
robot_4wd_firmware.ino
orcp2.cpp
orcp2.h
robot_sensors.cpp
robot_sensors.h
robot_4wd.cpp
robot_4wd.h
types.h
imu.cpp
imu.h

(from https://github.com/RoboCraft/robot_4wd/tree/master/orcp2)

5. edit robot_4wd_firmware.ino

for drive board - comment definition
#define IMU_BOARD
i.e. 
// #define IMU_BOARD

and vice versa, for sensor board comment definition:
#define DRIVE_BOARD

6. compile and load sketch into Arduino board

Done!