The robot builders over at Cellbots have been busy cranking out robots based around the Google Android OS. Their latest effort is Truckbot, an acrylic differential drive robot that relies on a Google G1 phone running the GNU/Linux-based Android OS combined with an Arduino. The robot can be teleoperated but also incorporates autonomous features such as cliff-detection to avoid falling off of tables. The video above demonstrates an ultrasonic sensor. See the additional videos after the break for examples of teleoperation and use of the G1's sensors for orientation. The Cellbots group has also released all their source code as Free Software under the Apache 2.0 license. You can use their software to build your own Cellbot with voice recognition, text-to-speech, compass orientation, teleoperation, GPS, and other cool features.