Adafruit’s Raspberry Pi Lesson 3. Network Setup

Overview

One of the first things that you will want to do is to get your Raspberry Pi connected up to the Internet.

In this lesson, you will learn how to:

• Connect using an Ethernet cable
• Use a WiFi adapter with both Raspbian and Occidentalis
• Find out the IP address of your Raspberry Pi

Using a Wired Network

The quickest way to get your Raspberry Pi connected is to use an Ethernet patch cable and just plug it into the back of your home network router.

As soon as you plug your Pi in, you should see the network LEDs start to flicker.

For most home networks, you should also be able to connect to the Internet without any further configuration. For this to work, your router should be configured for DHCP (Dynamic Host Configuration Protocol). This service runs on your home network router, dishing out IP addresses to any device that connects to it either through WiFi or by cable.

If DHCP is not turned on, on your home network router, then connect to its management console using a different computer that is already connected.

You should be able to find a setting somewhere that turns it on.

Buying a USB WiFi Adapter

Look for a WiFi adapter that supports the RTL8192cu chipset, as both the latest Raspbian and Occidentalis distributions both have support for this built-in and we’ve found its much faster than the Ralink chipsets

If you already have a WiFi adapter, just give it a go, even a lot of the very low cost budget adapters will work without any trouble.

WiFi does however use quite a lot of power, so check the power rating of your power supply. Some WiFi adapters require an external power supply to work well. We suggest the 5V 1A power adapter in our shop if this is the case. All of the WiFi adapters we have in the Adafruit shop will work just fine this way.

If you have a WiFi adapter plugged in, then you no longer have two free USB sockets available for your keyboard and mouse, so you may also need a powered USB hub.

Setting up Wifi with the Graphic Interface

Setting up WiFi requires that your router is broadcasting the SSID. Make sure you have “Broadcast SSID” set up on your router! This will not work with “private” SSID setups

Raspbian releases after 2012-10-28 include a WiFi configuration utility. You will find the shortcut for this on the Desktop. If you are using command-line tools or are logging in over Ethernet, check the next page for how to edit /etc/network/interfaces by hand

Step 1.

Double-click the icon and this is what you will see.

Step 2.

Click on the Scan button and a second window will open. Find your Wireless access point in the list and double click on it. This will open another window.

Step 3.

Enter your password in the PSK field and then click Add. When you look at the first window, you should see that the connection is all set up for use. You can connect or disconnect using the buttons. Notice also the IP address of the Pi is shown at the bottom of the window.

Setting up Wifi with the Command Line

This tutorial works best if your router is broadcasting the SSID. Make sure you have “Broadcast SSID” set up on your router! This may not work with “private” SSID setups

Setting up WiFi in Occidentalis, is also pretty straight forward. You just need to add the name of your wireless network (its SSID) and your password to a configuration file.

Step 1.

Boot the Raspberry Pi without the WiFi adapter plugged in.

Step 2.

Open a Terminal session by clicking on the LXTerminal icon, and enter the following command into it:

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1. sudo nano /etc/network/interfaces

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1. auto lo
2.  
3. iface lo inet loopback
4. iface eth0 inet dhcp
5.  
6. allow–hotplug wlan0
7. auto wlan0
8.  
9.  
10. iface wlan0 inet dhcp
11. wpa–ssid “ssid”
12. wpa–psk “password”

If you are using a ‘hidden’ SSID, try the following (hat-tip tohttp://ift.tt/1nRLYLu)

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1. auto lo
2.  
3. iface lo inet loopback
4. iface eth0 inet dhcp
5.  
6. auto wlan0
7. allow–hotplug wlan0
8. iface wlan0 inet dhcp
9. wpa–scan–ssid 1
10. wpa–ap–scan 1
11. wpa–key–mgmt WPA–PSK
12. wpa–proto RSN WPA
13. wpa–pairwise CCMP TKIP
14. wpa–group CCMP TKIP
15. wpa–ssid “My Secret SSID”
16. wpa–psk “My SSID PSK”
17.  
18. iface default inet dhcp

Step 3.

This opens an editor screen of the wifi configuration file you need to change.

The two places where you need to make a change are on the last two lines. Change the file so that it looks like this:

Of course, you should put in your network and password! Note that you need to keep the double-quote characters around your wireless network name and password.

This kind of editor does not let you use the mouse. Instead, use the cursor keys to move around the file.

Step 4.

When you have finished press [ctrl]x. This will ask if you want to save the modified files.

Press ‘Y’ and then Return to save the file with the same name.

Step 5.

Shut down your Raspberry Pi, plug the WiFi adapter in and start it up again. You should find that the Raspberry Pi connects using the WiFi adapter as it boots up.

Finding Your Pi’s IP Address

You can find the IP address of your computer, either by opening the WiFi setup tool again. The IP address will appear at the bottom of the Window.

If you are using Occidentals, or you want to do this over a command line terminal. Open up a LXTerminal window and type the following command:

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1. sudo ifconfig

Next to the wlan0 entry you will see inet addr: 192.168.1.10 which is the IP address of the Raspberry Pi.

Remember! If your IP address starts with 192.168 or 10.0 then its an internal address – that means you can get OUT to the Internet but you cannot have someone outside your home or network reach your Pi via the IP address. This is important if you want to have a webserver running on a Pi that outside people can reach. In general, its much safer to keep your Pi on an internal network so it can’t be hacked as easily!

Test and Configure

If you have X running, open the Midori web browser and navigate to the URL of your favourite electronics supplier.

If you are using a command line, the ping command can be used to see if you are reaching the internet. Try ping google.com orping adafruit.com to check if you can reach those sites!

Fixing WiFI Dropout Issues

If you find your module ‘drops out’ from time to time, you can fix it fairly easily with a command line fix (thanks perseus286!)

Create and edit a new file in /etc/modprobe.d/8192cu.conf

sudo nano /etc/modprobe.d/8192cu.conf

and paste the following in

# Disable power saving
options 8192cu rtw_power_mgnt=0 rtw_enusbss=1 rtw_ips_mode=1

Then reboot with sudo reboot

Click Here for the Next Lesson

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