|The keypad connected to my Iteaduino 2.2.|
I will have to find another way to connect it, as this connection uses pin 8 (ICP1), that I intend to use for the manchester decoding of EM4100 RFID tags. However this is no problem, as I think I will end up using a barebone Arduino for the finished product.
I am still waiting for the MIFARE reader kit, so next I will look at my $3 Nokia 5110 84x48 pixel display. It has a Philips PCD8544 controller using SPI for communication. It is well documented, and Adafruit has both a tutorial and a library for it.