A prior post talked about a lightweight and reliable method for sending push notifications from an Arduino to a mobile phone. In this post I’ll to describe my application for the notifications.

When looking for project inspiration I saw a couple of designs for monitoring a postal mailbox and sending a notification when the door was opened (e.g. when you get new mail). Those didn’t seem very useful but they did tickle a notion I’ve had of knowing if my garage door was left open for a period of time. I see this happen regularly in our neighborhood and it sometimes results in the loss of bicycles, tools and once even a car. In the spirit of truth-in-posting we once left ours open all night. Fortunately nothing was taken. Now on to the build…

The parts list, other than a basic pullup resistor and some wire, is pretty short and consists of

In simple terms the goal of the project is to send me an alert if the door is open longer than a specified period of time (e.g. 15 minutes) and to send me an update if the door closes after that time period. Quite simple eh? I also implemented a “health check” that enables the Arduino to ping my server periodically. A script runs on the server and if it doesn’t hear from the Arduino it too will send an alert letting me know there has been a monitoring failure. After all what good is a security device that fails silently?

If you’re interested in a project like this let me know and I can give you the source code (sketch).

[slideshow]