The "Pi of the Sky" robotic telescope has been designed for monitoring of a significant fraction of the sky with good time resolution and range. The main goal of the "Pi of the Sky" detector is to look for short timescale optical transients arising from various astrophysical phenomena, mainly for optical counterparts of Gamma Ray Burst (GRB). System design, observations methodology as well as developed algorithms also make this detector a sophisticated instrument looking for novae and supernovae stars and monitoring of blasars and AGNs activity. Final detector consists of two sets of 16 cameras, one camera covering field of view of 20°x20°. It follows that the full system will cover field of view of SWIFT BAT satellite. The final system is under construction now. Required hardware and software tests were performed with a prototype located in Las Campanas Observatory in Chile since June 2004. The most important result by the "Pi of the Sky" prototype so far was an independent detection and observation of the prompt optical emission from the naked-eye GRB080319B.© (2009) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.