In a meeting the other day and my boss asked for someone to come up with a non-verbal method of verifying a numeric code. My thoughts immediately went to 2 ten-key pads connected to an arduino or other micro computer and a red and green LED. The idea would be for both users to enter in the code on their respective pad and either get a green light for matching or red light for non-matching. With so many high-level projects these little computers can manage would something this low tech be possible?
Yes , sounds doable - might need to check you have enough I/O pins