https://hackage.haskell.org/package/wiringPi https://github.com/ppelleti/hs-wiringPi The most significant addition in this version is the wiringPiISR function, which makes it possible to get a callback when an input pin changes, thus avoiding the need to poll. In a future version, I might add a higher-level facility on top of this, such as the ability to update a TVar when an input changes. (Let me know if you have any thoughts on this.) New in 1.0.1: * Examples for Pi-LITEr and Fish Dish boards. * Added piGpioLayout as a synonym for piBoardRev, to reflect the name change in version 2.36 of the C library. * Addition of wiringPiISR function. (Contributed by Satoshi Ogata.) * Improvements to documentation and examples. About wiringPi: This is a Haskell binding to the wiringPi library, which allows you to interface with the GPIO pins on the Raspberry Pi. Unlike some other solutions for using the Raspberry Pi's GPIO pins, wiringPi provides access to more advanced features, such as enabling the internal pull-up or pull-down resistors. --Patrick