Lately i was busy in the hardware design of a personal robot named Chippu. It is an open source project and runs ROS, the same powerful code framework that runs on many robots like PR2. It is made as economical as possible. At present there is no on-board processing and it is done in a remote computer. But in near future, Chippu will shift to something like a beagleboard.
Talking about the hardware, Chippu uses an Arduino to connect to the remote computer through a USB link. The Arduino takes care of all the low level control functions like motor controls, servo controls, sensor integration etc. The Arduino runs a ROS node. The ROS nodes running on the computer can then communicate easily with the Arduino using the rosserial library. Two gear motors running at 60 rpm takes care of driving Chippu around. The gear motors are driven by the popular L293D H-Bridge. At present chippu doesn’t have any rotatory encoders for odometry and it will get it soon. Four servo motors are used in chippu, two for the pan and tilt of the head which contains a webcam and one each for the arm. The arm does nothing much than giving a pleasing visual feedback. In addition to the webcam, the head also features some ultra bright white LEDs and IR LEDs to enable Chippu to see in darkly lit environments. The LEDs are also controlled by arduino using pwm.
The following video shows keyboard tele-operation of Chippu.
The coding of Chippu is currently in progress and is expected to be continuously developing project. ROS nodes have been succesfully developed for keyboard teleoperation, Speech synthesis & speech recognition.
Chippu uses Festival for speech synthesis,
Julius in combination with voxforge to do speech recognition
OpenCV for vision
Apache as webserver, for teleoperation over networks
SSH for remote shell access,
and ROS as the meta-operating system running on Ubuntu 10.04 Lucid 64 bit with Python and GCC for C.
The project is currently under work and i will post updates soon. So watch out for more updates
Here are some build pics of Chippu: