This section explains the procedure for configuring the EV3 as a wireless LAN access point.

Since the procedure is almost the same as that for a Raspberry Pi, please refer to the following website for detailed information.

http://hara.jpn.com/_default/ja/Topics/RasPiE3839EE382A6E382B9E38292E784A1E7B79ALANE382A2E382AFE382BBE382B9E3839DE382A4E383B3E38388E58C96.html

Compiling hostapd with Realtek Device Support

Use the GW-USNANO2A wireless LAN adapter.

As described on the website above, the 8192CU chipset is not supported by hostapd by default. Therefore, enter the following commands in the cross-compilation environment and compile it.

 wget http://12244.wpc.azureedge.net/8012244/drivers/rtdrivers/cn/wlan/0001-RTL8188C_8192C_USB_linux_v4.0.2_9000.20130911.zip
 unzip 0001-RTL8188C_8192C_USB_linux_v4.0.2_9000.20130911.zip
 cd RTL8188C_8192C_USB_linux_v4.0.2_9000.20130911/wpa_supplicant_hostapd/
 tar zxvf wpa_supplicant_hostapd-0.8_rtw_r7475.20130812.tar.gz
 cd wpa_supplicant_hostapd-0.8_rtw_r7475.20130812/hostapd/
 make

After compilation is complete, transfer hostapd to the EV3.

 sftp robot@<IP address>
 put hostapd

Configuration

Static IP Address

Add the following entries to /etc/network/interfaces.

 auto lo
 
 iface lo inet loopback
 
 iface eth0 inet dhcp
 
 auto wlan0
 iface wlan0 inet static
 address 192.168.11.1
 netmask 255.255.255.0

Installing hostapd

Install hostapd with the following command.

 sudo apt-get install hostapd

After installation is complete, copy the hostapd file you transferred earlier to /usr/sbin.

 cp hostapd /usr/sbin/hostapd

Edit /etc/hostapd/hostapd.conf as follows.

Modify ssid and wpa_passphrase as appropriate.

 interface=wlan0
 driver=rtl871xdrv
 ssid=ev3_0
 hw_mode=g
 channel=6
 macaddr_acl=0
 auth_algs=1
 ignore_broadcast_ssid=0
 wpa=2
 wpa_passphrase=ev3atx9fr
 wpa_key_mgmt=WPA-PSK
 wpa_pairwise=TKIP
 rsn_pairwise=CCMP

Modify /etc/default/hostapd as follows.

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

Restart the network.

 sudo /etc/init.d/networking restart

Start hostapd with the following command.

 sudo /usr/sbin/hostapd /etc/hostapd/hostapd.conf -dd

At this point, the configured SSID should be visible from other PCs.

DHCP Server Configuration

Install the DHCP server with the following command.

 sudo apt-get install isc-dhcp-server

Modify /etc/dhcp/dhcpd.conf as follows.

 # option definitions common to all supported networks...
 #option domain-name "example.org";
 #option domain-name-servers ns1.example.org, ns2.example.org;
 
 ping-check true;
 
 #default-lease-time 600;
 #max-lease-time 7200;
 
 authoritative;
 
 subnet 192.168.11.0 netmask 255.255.255.0 {
 option routers 192.168.11.1;
 option broadcast-address 192.168.11.255;
 option subnet-mask 255.255.255.0;
 option domain-name "local";
 option domain-name-servers 8.8.8.8,8.8.4.4;
 default-lease-time 600;
 max-lease-time 7200;
 range 192.168.11.101 192.168.11.199;
 }

Modify /etc/default/isc-dhcp-server as follows.

 INTERFACES="wlan0"

Configuring the Startup Script

Finally, add the following entries to rc.local.

 ifdown wlan0
 ifup wlan0
 service hostapd start
 service isc-dhcp-server start

Before rebooting, if you have configured wireless LAN according to the procedure on this page, set Wireless and Networks → Wifi → Powered to OFF. Also set Wireless and Networks → Offline Mode to ON.

All procedures are now complete. Reboot the EV3 and verify that you can connect successfully.

If the connection fails, connect to the EV3 via a wired connection and verify that the configuration has been performed correctly.

Procedure for Starting the Access Point Using Button Operations

This section explains how to start the access point using the EV3 buttons.

First, create the following script file in /home/robot (named start_ap.sh in this example).

 #!/bin/sh
 sudo ifdown wlan0
 sudo ifup wlan0
 sudo service hostapd start
 sudo service isc-dhcp-server start

Change the file permissions with the following command.

 chmod +x start_ap.sh

This file will be launched from File Browser → start_ap.sh using the EV3 buttons. However, since it is not possible to enter a password when executing sudo from the EV3 button interface, configure sudo so that it can be executed without a password.

Enter the following command.

 sudo visudo

Then add the following lines.

 robot ALL=(ALL)     ALL
 %robot ALL=(ALL)     NOPASSWD: ALL

The setup is now complete. Launch File Browser → start_ap.sh using the EV3 buttons.