Chapter 6. Adding Cameras to Our Security System

Until now, we've been putting together the elements that will allow us to connect sensors to our alarm system to detect intrusions using either switches or passive infra-red motion detectors, which in turn will tell our Raspberry Pi that something has happened in a particular zone. These elements will all come together as a whole system later in this book.

Our system is now going to become a whole lot more sophisticated with the addition of cameras to take pictures and video clips, and e-mail them to us straightaway when it detects something.

We'll also use e-mail to send us alerts on our smart phone when we're out and about when any of the sensors in the system are triggered.

In this chapter we will cover the following topics:

• Setting up the Raspberry Pi camera module and learning how to capture stills and video images

• Learning how to overlay captured images with text and time-stamps

• Triggering image captures with a motion detector

• E-mailing the...

Prerequisites

You'll need the following parts for this chapter, on top of the components used in the previous chapter:

• A Raspberry Pi standard camera module

• A Raspberry Pi NoIR camera module

• An Infra-Red LED array and/or visible LED array

• A USB webcam

The Raspberry Pi camera module

The Raspberry Pi Camera Module is an official Raspberry Pi accessory that works with all models of the Pi, and can be used to take high-definition stills and video images. It connects directly to the Pi board's camera serial interface (CSI) port, which is dedicated to these modules to enable high-speed operation.

The camera itself is a 5 megapixel fixed-focus sensor supporting 1080p, 720p, and VGA video modes and still captures.

The official Raspberry Pi Camera Module

You can also obtain housings for the camera modules, which, unless you're going to build your own enclosure for the camera system, I recommend you use.

Raspberry Pi camera housings come in various colors and styles

Connecting the camera module

As previously mentioned, the module connects directly to the Raspberry Pi board via its dedicated camera interfaces, as shown in the following image. When connecting the camera, the contact side of the ribbon cable is toward the HDMI connector and the blue side...

Be a video star

Now that we know our camera module is working, we can try and capture some video. To do this, we'll use the raspivid utility. The following command will take 5 seconds of high-definition video and save the file to your Raspberry Pi:

$ raspivid –o test.h264 –t 5000

You'll notice that file is called test.h264—this is because the video is captured as a raw H.264 video stream. Unfortunately, not many media players will handle these files (although VLC player will—it rocks and handles practically anything you throw at it—get it on your PC at www.videolan.org).

If you want to play the file on smartphones and conventional media players, then we will need to wrap it in a container format, such as MPEG-4, and give the file a .mp4 extension.

To do this, we'll use the GPAC package, which is an open source multimedia framework. It comes with a utility called MP4Box, which is a tool we'll use to create an MP4 container for our video file:

1. First, install the GPAC package:

   $ sudo apt-get install...

You have new mail

Having the images stored on your Raspberry Pi is not really much use—ideally, you would want the images sent to you straightaway, as soon as they are captured, so that you can view them on your smartphone.

An easy, quick, and reliable way to do this is to simply have them e-mailed to you. Hence we're going to add an e-mailing functionality to our home security system so that image captures are attached to a message and sent to your e-mail address straightaway, which you can access from your smartphone. The images can then be removed from your Raspberry Pi to prevent the SD card space from being clogged up with these reasonably large files.

Setting up the e-mail sender client

Fortunately, there are some good packages available that will help us with this. Carry out the following steps to install the email packages we need:

1. Update the package installer with the following command:

   $ sudo apt-get update
   

2. Install and set up the SMTP client with the following command:

   $ sudo apt-get...

Night vision

The standard Raspberry Pi camera is great for taking daytime snaps of people walking up the garden path, but when it comes to night time shots, it's not really suitable. There are two ways of dealing with this: the first is to illuminate the capture area with a bright light when the PIR detector is triggered, and the second is to use the Raspberry Pi NoIR camera module and an infra-red LED array to let the camera see in the dark. More about that in a minute.

The Raspberry Pi NoIR camera module; it looks similar to the standard model

An illuminating experience

In order to switch on a light or LED array from the Raspberry Pi GPIO or our port expander circuit, we need something that will allow us to drive higher currents and voltages than can be provided by the GPIO ports alone.

A good candidate for this is the TIP120 Darlington transistor, which will allow us to switch on and off loads of up to 80V and 5 A from our GPIO pins. In our full system later on, we're going to use Port B...

Using USB cameras

Instead of using the Raspberry Pi Camera Module, it's also possible to use a standard USB webcam to take still images. You should be aware though that the dedicated camera module is far superior to a USB webcam in terms of image quality. Although, you may already have a webcam knocking about in your box of bits, so why not try it?

Installing the webcam

After you've connected your webcam to a USB port on your Pi, you can check whether it's been recognized using the lsusb command:

$ lsusb

I'm using a Logitech webcam that gets reported as follows with lsusb (Device 006):

pi@raspberrypi ~ $ lsusb
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 006: ID 046d:08d8 Logitech, Inc. QuickCam for Notebook Deluxe

Note

Not all webcams will work with the Raspberry Pi. Even though it may be recognized as a USB device, it might not actually work...

The multicamera setup

It may have occurred to you that the Raspberry Pi has only one camera module input. Now, this is obviously limiting if you want to have multiple cameras around your property that are triggered by motion detectors.

However, there is nothing stopping us from building standalone units that have a separate Raspberry Pi board with a PIR detector, Camera Module, and network connection, either using a Wi-Fi dongle or Ethernet.

Because you only need a single input to the Raspberry Pi to detect when the PIR motion sensor is triggered, you can use the on-board GPIO port to connect the sensor, rather than using a port expander. The Raspberry Pi will email the alert over the network, and could alert the main controller Pi if required—making it a slave sensor device.

You can readily obtain small PIR detectors, such as the Parallax one shown next, which you can mount onto a Raspberry Pi Case along with the camera module, creating a self-contained unit.

A Parallax PIR motion sensor (type...

Summary

In this chapter, we learned how to connect both Raspberry Pi camera modules and USB cameras to our Pi board in order to take image and video captures when required by our home security system. We also learned how to overlay our images with informative text and have the files immediately emailed to us.

In order to capture images from our camera at night, we also looked at ways to illuminate the capture area using both visible and infra-red lighting, with the ability to switch the lighting on and off as required by using a high-current Darlington transistor driver.

In the next chapter, we're going to get down to the business of putting together modules by building a mobile-optimized web-based control panel for our home security system. We'll learn how to set up a Web server on our Raspberry Pi and manipulate files using our Web control panel, which means that we'll start to explore how all of the elements we've encountered so far can come together as part of our final system.