The PL2303HX is a USB to UART TTL (Transistor-Transistor Logic) converter module that allows communication between a computer or other USB-equipped device and a UART device through a USB port.
The TCS34725 is a RGB and Clear light sensing elements IR blocking filter integrated on-chip and localized to the color sensing photodiodes minimizes the IR spectral component of the incoming light allows color measurements to be made accurately.