What better use for an advanced robot than emulating an ancient time keeping device? Jim Kelly has built a robot sundial using the LEGO NTX robotics kit. The biggest hitch was the lack of trig functions on the NTX brick. To get around that, he offloaded the trigonometry to a PDA. The robot uses a compass sensor and light sensor along with 3 motors and about 270 other LEGO parts. When activated, the robot sundial orients itself and then begins bluetooth transmission of the magnetic heading of the maximum reported light level to the PDA, which calculates and returns the time to the NTX. The Sundial is accurate to within 15 minutes. via The NTX Step blog.