Kevin- Lol! You are right- it would look very suspicious. I can see the bomb squad detonating your mailbox...
I am thinking a light sensor in the top rear of the mailbox. Then it can be discreet.
Clark- that is a brilliant use! I was going to use Twine with magnetic switch on the door. However what you describe is better yet and will not give me dozens of texts as the door is used normally.
This will be fantastic- Our home Wifi is, for reasons I am unsure of, separated into three different networks. I am certain the reason is very clever, but it makes using the Twine more of a challenge.
I just found another question where this was answered:
http://community.supermechanical.com/index.php?p=/discussion/52/longer-cable-two-sensors
So it seems that they are making a special 10 foot cable and we can try a commercial one but the signal …
+1 on logging based on time and a sensor variable. And +10 to the person who writes out idiot-proof directions for those of us who have never ventured into logging before.