If you need to
remotely control your robot or if you need to occasionally use
a numeric keypad with your device, but there is no room for it
or it simply does not have to always be attached to it, why
not use your infrared remote to do the task?
This assembly language source code for Atmel AVR
microcontrollers will allow you to decode IR signals from your
remote which uses Panasonic RECS80 protocol. It uses only 1
pin (Int0) as input, 2 interrupts (Int0 and Timer0), 8
registers and less than 100 words of program memory so even on
the tiniest AVR controller - ATTiny15L you will still have
plenty resources left for your main program logic.