Using Raspberry PI as Wireless AP

Before we start, please make sure your system requirements.

What's do you need?

1. A Raspberry PI
2. A boot SD card with default Raspberry PI image iso (Raspbian "wheezy")
3. A USB WiFi device which support "Access Point" mode and the driver is rtl8192cu

1. Install the necessary packages

sudo apt-get install hostapd bridge-utils

2. Configure

sudo vim /etc/default/hostapd

Add the following line to the bottom of the file.

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

Modified the config file

sudo vim /etc/hostapd/hostapd.conf

Add the following lines to the file.
You can change the "ssid", "wpa_passphrase".
Most the others examples use nl80211 as their driver, but Raspberry PI don't have the driver (default).
Therefore I can't start the service hostapd.
However I found some people use rtl871xdrv and they have the related hostapd binary file that supports rtl driver.
So... I use rtl871xdrv.

interface=wlan0                                                                                                                 
driver=rtl871xdrv
ssid=KenRaspberryPiAP
hw_mode=g
channel=6
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=safesync
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

3. Change network interface setting

sudo vim /etc/network/interfaces

auto lo
auto br0 
iface lo inet loopback
iface br0 inet dhcp
        bridge_fd 1
        bridge_hello 3
        bridge_maxage 10
        bridge_stp off 
        bridge_ports eth0 wlan0

allow-hotplug eth0
iface eth0 inet manual
allow-hotplug wlan0
iface wlan0 inet manual  

4. Replace the hostappd binary

Download

cd /usr/sbin
rm -f hostapd
wget http://dl.dropboxusercontent.com/u/13846584/hostapd

Change Permission

sudo chown root:root hostapd
sudo chmod 755 hostapd

5. Reboot

sudo reboot now

After reboot, you should see your own Raspberry PI Access Point(AP).