The PiMoroni Explorer HAT mounts on top of the Raspberry Pi and provides coloured LED’s, capacitive inputs and outputs, a mini breadboard, and 5v powered inputs and outputs. It has an easily available full python library, documentation and examples.
Learning Computer Architecture with the Raspberry Pi explains what each hardware component does, how they relate to one another, and how they correspond to the components of other computing systems. You’ll also learn how programming works and how the operating system relates to the Raspberry Pi’s physical components.
The PiMoroni Skywriter hat sensors your swipes or taps from up to 5 cm away. You can use the Python API to read x,y and z co-ordinates of your gestures. It is fully compatible with the Raspberry Pi A+, B+ and Raspberry Pi 2.