Charly's Column – Motion Detection

After a swarm of wasps finished off the first-generation Raspberry Pi I had been using in a birdhouse in my garden for the past five years, I knew it was time for a replacement – after all, there have been some massive technical advances in the meantime.

Let's look at my hardware first, and I mean the birdhouse. For my purposes, it has to be one with two chambers: one for the technology, and the other for the birds. Carpentry workshops operated by the prisons in North Rhine-Westphalia, Germany, provide good quality birdhouses in several kinds of wood [1]. I chose the high-rise model in Figure 1, which has two chambers arranged one above the other.

Figure 1: A comfortable villa for birds: the two-story birdhouse in Charly's garden.

A third generation Raspberry Pi with a Pi NoIR camera provides the livestream. As the name NoIR suggests, this is a model that can handle low light conditions, because it does not have an infrared filter. With a small infrared diode, which the birds do not notice, you have a perfect view of what is happening in the nesting chamber.

While I previously covered motion detection software in the December 2019 issue of Linux Magazine [2], I would like to introduce a software project that integrates all the necessary components and is very easy to install: the RPi Cam Web Interface [3].

As a base, you only need a recent Raspbian installation. You then call

sudo raspi-config

and enable the camera interface there. Next, clone the software with the following command:

$ git clone https://github.com/silvanmelchior/RPi_Cam_Web_Interface

In the newly created directory, call

sudo ./install.sh

sudo is required here, because the installation program has to install additional packages. During the installation, you can influence several parameters. Since the programmer chose sensible default settings, they don't really need to be changed unless you have low-performance hardware, such as a Pi Zero. In that case, you will want to replace the resource-hungry Apache web server with the more frugal lighttpd.

After a reboot, the livestream waits for me to access it on the Raspberry Pi's IP address (Figure 2). At the push of a button (motion detection start), I launched the motion detection setup. Let's hope that there is no swarm of wasps to spoil the fun this time.

Figure 2: The first potential tenants checking out the bird villa.