Chapter 5. Opening a Lock with an SMS

In this chapter, we are going to build another great application for secret agents: opening a door lock simply by sending an SMS! You'll just need to send a message to a given number and then you'll be able to control a door lock or any other kind of on/off digital device, such as an alarm.

For that, we are going to take a number of steps, as follows:

• First, we are going to use Arduino and the FONA shield from Adafruit in order to be able to receive and process text messages
• Then, we'll connect this to a relay and LED to see whether we can actually control a device by sending an SMS
• Finally, we'll see how to connect an actual electronic lock to the system

Let's start!