Domestic service robots are currently powered by the mains electricity. The growing multiplication of such devices negatively impacts our environment. In this study, we show the feasibility of harvesting energy from natural light in an indoor environment. The design of the harvester is carefully carried out using an experimental characterisation of several solar panels, while the boost converter is optimised to operate at low-light intensities and the robot is enhanced for low-power operations. The resulting harvester is then thoroughly characterised. Finally, a phototaxis experiment is conducted, proving the feasibility of recharging the robot solely by using this form of energy. The possibility of embedding energy harvesting in indoor mobile robots radically changes the potential impact of this technology in our society.