Hi,
I have experience for 20+ years in electronics/embedded development. I have several years of advanced AVR/arduino development, including library development from scratch. Practically all Arduino AVR boards used, like: 2009, 2010, UNO, MEGA, NANO, MICRO, MINI, etc. Several shields used like Ethernet (W5100, ENC28J60, etc.) with various IP protocols implementation, various graphical TFTs with and without touchscreen and various BUS types (parallel, SPI, I2C, etc.), all kinds of sensors and buses, serial and parallel memories, etc.
My understanding from your description, you want to read the ambient light in lux through a BH1715 I2C sensor and when a pre-defined threshold is reached, activate a light source that will be close-coupled to the "LED light with PIR sensor", turning on that LED light. Please correct me if I am wrong.
If this is the case, I propose using an Arduino Uno (or similar, like nano, etc. AVR based), that interfaces to the BH1715 sensor through I2C bus and one digital output connected the the light source, this can be an LED, or some other interface allowing more power/voltage (relay, SSR, transistor, etc.).
I have plenty arduinos for testing, but would require a BH1715 sensor for development.
If you are interested in my bid, please let me know some more details about your project. Feel free to contact me.
Regards,
Carlos.