This page lists the 'fantasy' features that such a key safe could have. Please let me know if you have any other suggestions.
I see the key safe working in one of two ways, depending on how it's engineered:
Features for this device could include:
I see the software working in one of two ways:
If you're interested, the basic idea is that it's based on a standard digital safe which you can buy then snip one of the wires in order to allow the timer or microprocessor to control it - so that answers any questions about how secure it would be.
Take a look at the safe I've already built (base on the 'Standard timer unit' plan above) here.
I think this should be availble from anyone's local hardware or stationary store. I'd be very interested if you could let me know how much a safe like this is in your local area, and where that is (what store in which country).
The Microprocessor I had in mind is a AVR board which is very cheap and resonably functional, specifically this ATtiny26 board.
I'm just trying to find out if there's a potential market for these things. If you're interested in the idea, you could help me out a lot by answering the following questions: