I am looking for an inexpensive way to have a user enter a security code and then enter a timer countdown value that will then activate a relay or contactor. The access panel could not be tampered with or timer reset unless you knew the security code. I was thinking a keyed switch would be the easiest way but would not offer any duration, simple on or off. Any ideas on harware - I was thinking os some digital lcd hooked to a keypad of some sorts. But this is outside my range of expertise.
Thanks in advance