This is a very small light sensor. A photo resistor (also known as a photodector, or photocell) changes resistance depending on the amount of light it is exposed to.
Beacons are mounted on walls or ceilings to measure distance to other beacons and “hedgehog” using ultrasonic pulses. They communicate with router wirelessly in ISM band. Powered by LiPo battery or USB. Indoor Positioning System (IPS)
This aluminum heat sink is designed for integrated circuits (IC) of electric components. It's easy to use, and provides the perfect cooling effect for your project.