EnOcean introduces the STM100, a solar-powered wireless sensor module. Within its custom two-stage solar cell, one stage provides quick startup energy while the other charges an onboard energy reservoir. Designed to operate indoors, the device requires 200 lux to generate energy (typical lighting values in a building range from 200 lux in hallways, 500 lux on desktops and up to 1200 lux in display cases). The unit is comprised of a solar cell energy source, an energy reservoir, analog and digital sensor connections, a microprocessor for sensor control and a radio transmitter-all packed into an 0.8 inches× 1.6 inches× 0.4 inches footprint. The STM100 stores sufficient energy to operate continuously for up to five days in complete darkness.