A study on light energy harvesting from indoor environment: The autonomous sensor nodes

Micro-level energy sources from the ambient environment can be a viable alternative to increase the life of the sensor nodes from a WSN network. Harvesting energy from the environment - particularly solar energy, is a technique that can support the operation of the sensor nodes. The power extracted from the luminous radiation is extremely variable, depending on day/night alternation, atmospheric conditions, temperature, geographical location, indoor or outdoor environment - which makes the energy harvested insufficient for use as an exclusive power source to supply sensor nodes. A special case is the indoor environment, in which the solar radiation is strongly reduced, compared to the outside environment, and artificial lighting levels are usually below 1000 Lux. We made experiments on an indoor solar cell using illumination from three different sources: fluorescent, incandescent, LED. Detailed measurements, performance comparisons, and conclusions are presented.