The design choices for implementing the hardware components of this lighting concept were driven by the guiding principles of safety and speed. A simplified diagram with notes follows:

Concerns around safety meant we didn't want to be implementing too much of our own custom circuitry in this project, least of which those components which would be in contact with mains (AC) voltage. Additionally, dedicating a separate controller to lighting control as documented below would facilitate building isolation between the AC elements of the system and the other sensors.

Speed of implementation also played a role here. By using retail boards we hope to more quickly implement and test our idea by avoiding any troubleshooting which would be related to custom hardware. 

Note that the design as documented below accommodates up to four independently controlled lighting channels. Though we will likely begin our testing with two channels we have designed a system capable of up to four channels to determine the benefit this could provide. One of the outcomes we may identify is the value added by a 3rd or 4th lighting source.