Phosphorescent Markers for Visible Light Sensing Put into Practice

In our last year's contribution to MIPRO we showed how phosphorescent markers based on Ruthenium and Platinum complexes can be utilized in combination with Backscattered Visible Light Sensing (BVLS) to perform sensory tasks such as identification or distance estimation in a simplified experimental setup. Based on measuring the decay time after a light stimulus, we showed how the marker was clearly distinguishable from optical reflections of various surroundings. In this manuscript, we present our achieved advancements of this approach towards a first real world application in the field of autonomous robots. In current autonomous robots laser-, wire-, magnetically-controlled or even camera-based systems are used for navigation. In our work, we placed a small 3D-printed element containing only one LED, a photomultiplier and a microcontroller on a robotic platform and phosphorescent markers on certain spots on the room floor. The performed comprehensive real world experiments showed that not only the identification of the different markers was achieved, but that this identification was achieved independent from the ambient lighting conditions ranging from no ambient light to a sunlit room. Discussing our achieved results, we will outline how BVLS with phosphorescent markers can be used in such applications to overcome current limitations or shortcomings of other technologies.