### Infrared LED and Photodiode  The sketch above describes an Infrared sensor that detects reflected light from an object. <!--  -->  This is a schematic for one way to put it together.  Here it is on a large circuitboard (left) and more compactly, on a small protoboard (right).  The signal from an object that passes ~two meters in front of the sensor. ### Examples <a href='https://silviafesta.github.io/PHYS_S-12/Assignments/assignment6.html'> Silvia</a> <br> <br> <!-- ### Micro A miniaturized version of this sensor works on much smaller scales. Range is ~0 - ~10 mm with ability to see motion less than 1 mm. This sensor also detects differences in reflectivity, so it could be used for robotic line-following and similar applications.  [Optek OPB710 datasheet](https://www.ttelectronics.com/TTElectronics/media/ProductFiles/Optoelectronics/Datasheets/OPB710-730.pdf) Can purchase from Digikey. Requires external components. See Rob for details and samples of working modules. --> _Thanks to Rob Hart, Gabby Perry_