The library gives control over up to 16 parallel working PIR devices over I2C. The idea for this library came up in a discussion about how to fully cover an area with PIR sensors without blind spots ...
The library is experimental as the functionality is not tested with hardware yet. The AD5231 is a single channel, 10 bit = 1024 step, SPI based potentiometer, the AD5235 is a dual channel version.