I'm a breakout board for the Raspberry Pi . I make it easy to connect electronics.
The toughest part of my design was making me fit inside a Raspberry Pi. The existing Raspberry Pi headers actually go all the way through my board and I sits approximately 2mm above the Raspberry Pi (very close). It's almost as if I'm part of the original board.
Because I sit so close to the Raspberry Pi, care has been taken to ensure that my thru-hole components avoid components on the Raspberry Pi board (so they don't short them out), and to avoid restricting air getting to the main ARM processor.