Motion-sensitive position sensor using bacteriorhodopsin

A concept of motion-sensitive position sensing that uses a film of bacteriorhodopsin (bR) treated with a high-pH buffer is proposed. The polarity of photo-emf, which depends on the excited intermediates of the bR molecule, can be used to determine movement direction. The M intermediate state with a long lifetime can be used to record the initial position. The bR-based position sensor can sense two positions of a moving object at two different times.