This study proposes a sub-kHz clock generator by the room light illumination designed on-chip CMOS LSI chips. It generates a clock from a flicker in room light by receiving on-chip integrated photovoltaic cell. and extracts by low-pass filters. a comparator. https://www.nacrack.com/mega-pick-As-for-Me-and-My-House-Wall-Decal-in-Hebrew-Yahauh-flash-find/