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 ...

This library uses a PCF8575 to read the pulses of a rotary encoder. As a PCF8575 has 16 lines up to 5 decoders with a switch can be read over I2C. The PCF interrupt line can be used to detect changes ...