Time bomb

[Ioannis]

OK, I sawit now that I am on my PC.

@ pedja089: This is the general idea, but if the secret combination is revealed once, then we lost one round in this game.

If the device has an LCD, it could show the lock code and expect an reaction depending on that code. This code would be different each time.

So the combination is somewhat encrypted.

It would be nice to have this option on non LCD devices too.

Ioannis

[pedja089]

It is, but if they pay you for prototype that is it...
Or you can put some connector(3 pin,Vcc,Gnd,Data), and create some type of "activator device" that can activate just 1 device...
If you tell us what is device that you want to protect, maybe you get more ideas...