Unlock a box remotely?

[Aerobyrd93]

Okay, so my friend and I have a game we are making. The game calls for a box which could be at his house in one state, and be unlocked by me in my house in another state at will. Once finished, the box would then be closed again at my friend's house, who would then be unable to open it until unlocked by me again. Can anyone offer guidance as to how one would go about doing this?
I hope this is clear, really it just comes down to being able to provide a 1/0 input to a device at a distance as frugally and reliably as possible. Both locations will have both wifi and router access, whichever is easiest to deal with.

Thanks!

[Muttley Snickers]

If the remote site has a telephone then DTMF is a valid option and if there is an existing security alarm system at the premises then this could be utilised easily depending on the particular system, on most systems an output can be turned on or off by a remote connection via the telephone network including PSTN, GSM and GPRS.

Radio CTCSS tones could also be used again depending on the distance involved and as mentioned below a particular tone could enable or disable an output, plenty of options including WAN.

 

[SpidersWeb]

I was thinking Arduino with Wifi shield or similar.
I can't offer much more than that, would just be the first thing I'd google.

[NiHaoMike]

What about a tone detector and just play the tone over the phone? Not very secure but as it's just a game, I don't think security is particularly high on the list.

[mtdoc]

ESP 8266 and a small servo motor for the lock.  I think Dave had an item on a recent mailbag that used a small servo to lock a box.

Or instead of the servo to do the locking - you could use one of these small push-pull solenoids

[boffin]

Electric Imp.  Dead easy to set up.   Simple web request from one side to unlock

[Delta]

This all sounds very kinky...!

[Jeroen3]

You can use two standard cellular controlled relay boxes. These you can program to act on inputs to text the other box.

Or diy with a Particle Electron (former spark core).