Static IP Address

The standard Raspbian image provides a capable Linux system, which when plugged into a network, uses DHCP (dynamic host configuration protocol) to automatically assign an IP address to it. If you’d like to connect to it remotely from a desktop or laptop, then the dynamic IP address that DHCP assigns is problematic.

In this example, the Raspberry Pi is identified on 192.168.1.77, complete with its MAC address (these appear above the line where “Raspberry Pi Foundation” is reported). While this discovery approach works, it does takes time and is inconvenient.

If you’d prefer to change your Raspberry Pi to use a static IP address, see the “Wired Ethernet” section in Chapter 8 for instructions.

Using SSH

Files can also be copied to and from the Raspberry Pi, using the scp command. Do a man scp on the Raspberry Pi for usage information.

Here, I’ve specified the Devuan Linux address (alternatively, an /etc/hosts name could be used) and pointed the Raspberry Pi to use Linux’s display number :0. We run the xpdf command in the background so that we can continue to issue commands in the current SSH session. In the meantime, the xpdf window will open on the Linux screen, while the xpdf program runs on the Raspberry Pi.

This doesn’t give you graphical access to the Pi’s desktop, but for developers, SSH is often adequate. If you want remote graphical access to the Raspberry’s desktop, one option is to use VNC.

VNC

If you’re already using a laptop or your favorite desktop computer, you can conveniently access your Raspberry Pi’s graphical desktop over the network. Once the Raspberry Pi’s VNC server is configured, all you need is a VNC client on your accessing computer. This eliminates the need for a keyboard, mouse, and HDMI display device connected to the Raspberry Pi. In other words, you can run the Pi “headless.”

Getting VNC working requires a bit of setup. Raspbian Linux has taken measures to make it easy. If not set up correctly, the VNC viewer will just provide a black screen when you try to log in.

To use VNC, you must have the desktop software installed (GUI). This will also make it easier for you to get it configured. If you have a Raspbian Lite distribution installed, it will not include the necessary desktop server software.

Start up the graphical desktop, then from the Raspberry icon (at top left), pull down the menu and select “Preferences,” and choose “Raspberry Pi Configuration.” That should bring up a dialog box like the one in shown in Figure 2-1.

You may already have the “Boot” option set to “To Desktop” but otherwise click that now. This will cause the desktop software to start after a boot so that you can connect to it through VNC.

After you have configured the desktop to start after a reboot, you also need to enable the VNC server as shown in Figure 2-2, by clicking on the “Interfaces” tab.

In the Interfaces dialog, click the VNC radio button labeled “Enable.” Click OK at the bottom right to save your settings. Then reboot your Pi. Allow time for a reboot and for the graphic desktop to start.

VNC Viewers

To access the VNC server, a corresponding VNC viewer is needed on the client side. One solution is to use the free realvnc viewer from:

https://www.realvnc.com/en/connect/download/viewer/

From that website, you’ll find download links for your favorite desktop, as depicted in Figure 2-3. Ignore the site’s reference to “VNC Connect.”

Download and install as appropriate for your desktop platform.

When you start the viewer, you will get a small dialog box similar to the one shown in Figure 2-4. Icons will exist (like the one shown) once you have successfully logged in.

Once you have successfully connected and logged in, you should have your Pi desktop displayed for you. Figure 2-5 illustrates a desktop window (on a Mac).

If your VNC viewer connects and seems to hang, be patient. The rate of your VNC screen updates will depend upon the ability of your network to transfer that graphic data. I found that I was able to use VNC with the Pi 3 B+ using a WIFI connection, without too much delay.

While the VNC facility is great for providing remote graphical desktop access, it probably goes without saying that the performance won’t be suitable for viewing video or fast action games.

Black VNC Screen

If you change the configuration of the Pi to boot to command-line mode (see Figure 2-1 button “To CLI”) instead of the desktop, you will experience a black screen when you use VNC Viewer (see Figure 2-6). Selecting command-line mode causes the desktop software not to run, even though you may have VNC enabled (Figure 2-2 “Enable”).

To regain VNC desktop access, you must change the configuration to “To Desktop” (Figure 2-1), and reboot. The alternative is to go to the command line (console or ssh) and start the X server manually. From the console login, simply do:

$ startx

From an ssh session, you'll need to be root (using sudo):

$ sudo -i

root@pi3bplus:~# startx

After giving the server software time to start up, the VNC Viewer should be able to attach to your desktop. Of course, if you log that ssh session out, the server will also exit and terminate desktop access.

Breadboard Setup

It is possible to work without a breadboard and Pi T-Cobbler adapter, but you will find that experiments are much more fun with a quality breadboard and adapter. A recommended T-Cobbler can be purchased from Adafruit ® and is illustrated in Figure 2-7 alongside a cheap copy.

https://www.adafruit.com/product/2028

Summary

With these details out of the way, the remainder of the book can focus on the various resources that the Raspberry Pi has to offer. The Pi has much to offer, so let’s get started.