  A liquid marble is a liquid droplet coated by a hydrophobic power. The liquid
marble does not wet adjacent surfaces and therefore can be manipulated as a dry
soft body. A Belousov-Zhabotinsky (BZ) reaction is an oscillatory chemical
reaction exhibiting waves of oxidation. We demonstrate how to make a
photo-sensor from BZ medium liquid marbles. We insert electrodes into a liquid
marble, prepared from BZ solution and coated with polyethylene powder. The
electrodes record a potential difference which oscillates due to oxidation
wave-fronts crossing the electrodes. When the BZ marble is illuminated by a
light source, the oxidation wave-fronts are hindered and, thus, the electrical
potential recorded ceases to oscillate. We characterise several types of
responses of BZ marble photosensors to various stimuli, and provide
explanations of the recorded activity. BZ liquid marble photosensors may find
applications in the fields of liquid electronics, soft robotics and
unconventional computing.
