thiagozs / routerypi

📶 RouteryPi is a simple WiFi access point made out of a Raspberry Pi Zero W.

RouteryPi

Summary

RouteryPi is a WiFi access point originally based on the Raspberry Pi Zero W. Together with a nice looking case and some status LEDs it makes a fun alternative to a commercial AP because of easy programming and customization. The only downside of using a Raspberry Pi is it's relatively slow networking speed compared to high quality retail APs - nevertheless it has great potential and makes an even better addition if you want to upgrade some generic old AP that you found in your basement!

Hardware

This will run on any newer Raspberry Pi generation aiming at the ones with onboard WiFi, however this probably also works with compatible WiFi and LAN dongles.

To get the best performance possible use the latest full-size Raspberry Pi available.

Software

This build uses the latest version of Raspbian which is Raspbian Stretch. You can download it on the official Raspberry Pi website, at https://www.raspberrypi.org/downloads/raspbian/. I guess you already know how to flash the image onto the SD Card - if you don't however, have a look at this tutorial: https://www.raspberrypi.org/documentation/installation/installing-images/

The heart of this whole installation will be 'hostapd' and 'bridge-utils' because we will be using the Pi as a network bridge between the LAN and WiFi. This means that you will need an additonal DHCP and DNS server. Nevertheless, this simplifies the whole installation a lot and makes it less error-prone. If you already have a router (which I assume you do) you can connect it to your RouteryPi and everything will work out of the box.

You will need no additional drivers at all!

Installation

Preparation

The first step is, obviously, to install the image onto the uSD Card and booting it up. The first boot usually takes longer than a normal startup because the Pi has to do first time stuff like generating new SSH keys and so on.

Then use sudo raspi-config to configure the Pi to your likings.

Now update it using sudo apt update && sudo apt full-upgrade - once it's done reboot it and we'll start with the actual AP installation.

AP setup

Firstly, install hostapd and bridge-utils with the following command.

sudo apt install hostapd bridge-utils

Now comes the important part. The next step is editing the hostapd.conf.

sudo nano /etc/hostapd/hostapd.conf

If the file is not empty just delete it's content. We will be using a custom config anyways. The minimal config that you should use looks like that:

# Bridge mode
bridge=br0

# Networking interface
interface=wlan0

# WiFi configuration
ssid=RouteryPi
channel=1
hw_mode=g
country_code=US
ieee80211n=1
ieee80211d=1
wmm_enabled=1

# WiFi security
auth_algs=1
wpa=2
wpa_key_mgmt=WPA-PSK
rsn_pairwise=CCMP
wpa_passphrase=SomeStrongPassword

Just paste the text into the hostapd config file, edit country_code=US to your country, save it and you're good to go.

To create and use the network bridge we only have to edit one more file. Now edit the network interfaces file like that:

sudo nano /etc/network/interfaces

Delete anything that's in here and paste the following configuration:

auto lo
iface lo inet loopback

# Ethernet
auto eth0
allow-hotplug eth0
iface eth0 inet manual

# WiFi
auto wlan0
allow-hotplug wlan0
iface wlan0 inet manual
wireless-power off

# Bridge
auto br0
iface br0 inet dhcp
bridge_ports eth0 wlan0
bridge_fd 0
bridge_stp off

This will result in the Pi using DHCP which means it can be used in any network. The downside of this is that you have to find out the IP address if you want to, let's say, use SSH. You could use a static IP address by changing the br0(!) interface config a little bit - just google 'static ip raspberry pi'. (For the lazy: https://duckduckgo.com/?q=static+ip+raspberry+pi)

Final steps

After you did a quick reboot using sudo reboot, you can start testing the whole thing. To test the hostapd config use this command: sudo hostapd /etc/hostapd/hostapd.conf. Note: If it does exit without you doing something, then there is something wrong with it. To go into debug mode use sudo hostapd -dd /etc/hostapd/hostapd.conf.

While testing the hostapd config you can also try connecting as a client. If you've done everything correctly you should be able to do so without any problems.

To enable hostapd to run upon boot you have to edit one last file.

sudo nano /etc/default/hostapd

Now paste this text into the file and save it:

RUN_DAEMON=yes
DAEMON_CONF="/etc/hostapd/hostapd.conf"

You're ready to go! From now on hostapd will start whenever your Pi boots up.

Speed

I tested my RouteryPi (Raspberry Pi W) under the following conditions:

One thing to take into consideration is that I (unfairly) tested my 5GHz WiFi which the Raspberry Pi Zero W cannot provide. I have to admit the RouteryPi's results are not that great, especially compared to my normal connection. But if you don't have a fast connection in the first place, this will be sufficent. Although the results seem pretty poor, I tested if you could watch Full HD (1080p) Youtube videos and play a little game like Minecraft on a server and it worked just fine!

Optional

• You could add an automatic speedtest with speedtest-cli-extras by utilizing crontab and outputting the results in a file. You'll have more convincing arguments when contacting your ISP in case something's not working again ;)

• You could remove some unused software from your pi to decrease the disk size even more - although this will only clean up some 10s of MBytes. Stuff you could remove would be e.g. vim-common, triggerhappy, bluez and so on. You can get a list of all installed packages by typing apt list --installed. Don't forget to do sudo apt autoremove afterwards!

• You could also solder an external antenna onto the Pi if you aren't satisfied with it's range. The Pi Zero W has tiny solder pads for soldering a U.FL RF connector. Together with a small adapter cable you could use your standard WiFi antennas. You can read into this with a nice tutorial like this one: http://www.briandorey.com/post/Raspberry-Pi-Zero-W-external-antenna-mod

• Security related: Raspbian Stretch is no longer vulnerable to the WPA2 Krack attack. Since the system got patched you are totally safe with using any Raspberry Pi as AP or client as long as all your other devices are secure. So please always update your system!