Why not just use morse code?  Anybody could learn 2 or 3 letters, and morse code
 decode with a PIC is not hard, you only have to deal with ratios, and assume th
e first press is a dot or a dash, because the lock 'knows' what letter to expect
 first.

   di di di di   pause    di dit

Regards,
  Ron Fial

At 07:27 PM 4/7/99 +0200, you wrote:
>>   I would like to make a PIC single-button "combination lock" for my
>>workshop door. This is not a high-security situation (the door is normally
>>unlocked), I just want to do it for fun and to learn something.
>>   The way the lock would work is that you would push the button in some
>>rhythm such as that of "shave and a haircut, two bits". This is only an
>>example, any rhythm could be used. This and only this would activate the
>>solenoid lock.