Custard pi system custard pi custard pi 2 ready built this custard pi extension card provides access to a range of analogue and digital inputs and output when connected to a relevant raspberry pi there are 4x open collector digital outputs 4x buffered digital inputs 2x 12 bit analogue outputs 2x 12 bit analogue inputs the card gives built in protection ensuring that all pins are protected from accidental connection to a high voltage when the card is plugged in two leds on the 5v and 3