When people take photographs using their cellphones eg at a concert, those cameras on board which have flashguns greatly deplete battery reserves because the cameras work independently.
Today’s invention is a way for such cellphone cameras to cooperate and share their flash illumination, so that everyone has enough light to take their shot.
When many people are poised to take a photo at the same venue, with their fingers on the shutter release at the same time, their cellphones could communicate this fact and calculate how much flash energy should be supplied in total. This would then allow the devices to share the load and individually produce only a small amount of light.
A more advanced version of this could, using GPS, take the relative positions and even orientations into account to create a well lit scene from almost all shooting positions.