Domain Presentation

Here is the google docs link to my Powerpoint presentation which I recently presented to the class.

https://docs.google.com/presentation/d/1FXcSMFlPn0nIsB0yet2WYVQCi9WNr3lQt7EEMXUay00/edit?usp=sharing
     

HTTP SERVER ON PI.

Accessing wifi in Arduino

 open the serial monitor and enter the code given down below.

Code: 

#include <ESP8266WiFi.h>
	const char* ssid = "aneesh";
	const char* password = "raspberry";
	const char* host = "www.google.com";
	void setup() {
	Serial.begin(115200);
	delay(100);
	// We start by connecting to a WiFi network
	Serial.println();
	Serial.println();
	Serial.print("Connecting to ");
	Serial.println(ssid);
	WiFi.begin(ssid, password);
	while (WiFi.status() != WL_CONNECTED) {
	delay(500);
	Serial.print(".");
	}
	Serial.println("");
	Serial.println("WiFi connected");
	Serial.println("IP address: ");
	Serial.println(WiFi.localIP());
	}
	int value = 0;
	void loop() {
	}

Arduino on PI

• The first step is to load the Arduino environment to PI, by using the following commands

 sudo apt–get update

 sudo apt–get dist–upgrade

• Next, Install Arduino IDE with,

sudo apt–get install Arduino (Click Y to add any dependencies)

•  To disable the serial login (for Raspberry- Pi 3),

 sudo systemctl stop serial–getty@ttyS0.service

 sudo systemctl disable serial–getty@ttyS0.service

•  The next step is to disable the boot info, for this we need to edit the             /boot/cmdline.txt file by deleting the “console=serail0,115200″ as shown.

 dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p6 rootfstype=ext4 elevator=deadline rootwait 

To link the serial port to the Arduino IDE, we create a permanent link that maps AMA0 to S0.

• Now create a file by “ sudo nano"

Enter the following code in the newly created file

KERNEL==“ttyAMA0”, SYMLINK+=“ttyS0”,GROUP=“dialout”,MODE:=0666
KERNEL==“ttyACM0”, SYMLINK+=“ttyS1”,GROUP=“dialout”,MODE:=0666

and save it to: /etc/udev/rules.d/

And then to link the new avrdude-autoreset to avrdude so that the new version runs instead.

sudo ln –s /usr/bin/avrdude–autoreset /usr/bin/avrdude

• Adding the sleepy Pi to the Arduino environment, to run the Arduino environment we need to create the sketchbook folder and then “hardware” & “Sleepy_pi ” in sketchbook.

 mkdir /home/pi/sketchbook
 mkdir /home/pi/sketchbook/hardware
 mkdir /home/pi/sketchbook/hardware/Sleepy_pi

• Now create another file “boards.txt” in Sleepy_pi folder and the file contains the following code,

sleepypi.name=Sleepy Pi

sleepypi.upload.protocol=arduino

sleepypi.upload.maximum_size=30720

sleepypi.upload.speed=57600

sleepypi.bootloader.low_fuses=0xFF

sleepypi.bootloader.high_fuses=0xDA

sleepypi.bootloader.extended_fuses=0x05

sleepypi.bootloader.path=arduino:atmega

sleepypi.bootloader.file=ATmegaBOOT_168_atmega328_pro_8MHz.hex

sleepypi.bootloader.unlock_bits=0x3F

sleepypi.bootloader.lock_bits=0x0F

sleepypi.build.mcu=atmega328p

sleepypi.build.f_cpu=8000000L

sleepypi.build.core=arduino:arduino

sleepypi.build.variant=arduino:standard

8. As a final step, Reboot the Pi to complete and load all changes.

 sudo reboot

HTTP Server on PI

 HTTP Webserver on Pi to host a full website or to display some information to other machines on our network. There are various web server that are available with different advantages and usage. Among them, I choose Apache, which is a popular web server application and install it on Pi.

• Install Apache2 package by ” sudo apt–get install apache2 –y”
• To Test the webserver,
• We have a test HTML file in Apache folder, so when we type our Pi’s IP address (like http://198.162.10.22) we will get a default web page as shown in the following figure.

If we see the default page in the browser, it means that the Apache is working.

References:

• http://spellfoundry.com/sleepy-pi/setting-arduino-ide-raspbian/
• https://www.raspberrypi.org/documentation/remote-access/web-server/apache.md

IN CLASS HOST-Access Point SETUP

In this experiment, the aim is to make raspberry pi as an access point of Wifi.


Items Required:

• Raspberry Pi. 
• Ethernet cable.
• WiFi adapter.
• SD Card with Raspbian installed in it.
• Power supply for your Pi & a Micro USB cable.

This post is about the experience of Host access point setup in class:

• Connect Raspberry Pi to the router.
• Change the password into desired one from "raspberry" which is by default.

Now getting into the protocols and type out commands in the command-line interpreter of the Raspberry Pi:

• The first step is to install the required packages for setting up access point by 

"sudo apt-get install dnsmasq hostapd "

( 'hostapd' - This is the package that allows you to use the built in WiFi as an access point. 'dnsmasq' - This is a combined DHCP and DNS server that's very easy to configure).

• Since I have used Raspberry Pi-3 which has very latest version of the RaspianThe interface configuration is handled by dhcpcd. It shall ignore wlan0, as we will be configuring it with a static IP address elsewhere. we do this by opening dhcpcd configuration file with "Sudo nano /etc/dhcpcd.conf" and add the following line in the dhcpcd "denyinterfaces wlan0".

• Static IP needs to be configured, with “sudo nano /etc/network/interfaces” and edit the wlan0 section should look as follows:

allow-hotplug wlan0  

iface wlan0 inet static  

    address 172.24.1.1

    netmask 255.255.255.0

    network 172.24.1.0

    broadcast 172.24.1.255

#    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

Now, restart dhcpcd with sudo service dhcpcd restart and then reload the configuration for wlan0 with sudo ifdown wlan0; sudo ifup wlan0.

• Next step is to configure hostapd by creating a new configuration file sudo nano /etc/hostapd/hostapd.conf with the following contents:

# This is the name of the WiFi interface we configured above

interface=wlan0

# Use the nl80211 driver with the brcmfmac driver

driver=nl80211

# This is the name of the network

ssid=Pi3-AP

# Use the 2.4GHz band

hw_mode=g

# Use channel 6

channel=6

# Enable 802.11n

ieee80211n=1

# Enable WMM

wmm_enabled=1

# Enable 40MHz channels with 20ns guard interval

ht_capab=[HT40][SHORT-GI-20][DSSS_CCK-40]

# Accept all MAC addresses

macaddr_acl=0

# Use WPA authentication

auth_algs=1

# Require clients to know the network name

ignore_broadcast_ssid=0

# Use WPA2

wpa=2

# Use a pre-shared key

wpa_key_mgmt=WPA-PSK

# The network passphrase

wpa_passphrase=raspberry

# Use AES, instead of TKIP

rsn_pairwise=CCMP

"sudo /usr/sbin/hostapd /etc/hostapd/hostapd.conf" can be used to verify if the hostapd is working.

Until this stage was the work done in the class and rest was done as a homework assignment. The post followed by this post will clearly explain how it is done.

Open up the default configuration file with sudo nano /etc/default/hostapd and find the 

line #DAEMON_CONF="" and replace it with DAEMON_CONF="/etc/hostapd/hostapd.conf"

•  To Configure DNSMASQ create a new file with

sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig

sudo nano /etc/dnsmasq.conf

and paste the file with the contents as follows:

interface=wlan0      # Use interface wlan0  

listen-address=172.24.1.1 # Explicitly specify the address to listen on  

bind-interfaces      # Bind to the interface to make sure we aren't sending things elsewhere  

server=8.8.8.8       # Forward DNS requests to Google DNS  

domain-needed        # Don't forward short names  

bogus-priv           # Never forward addresses in the non-routed address spaces.  

dhcp-range=172.24.1.50,172.24.1.150,12h # Assign IP addresses between 172.24.1.50 and 172.24.1.150 with a 12 hour lease time.

• Now the next step is to Setup IPv4 forwarding

This step enables packet forwarding

open up the sysctl.conf file with sudo nano /etc/sysctl.conf, and remove the # from the beginning of the line containing net.ipv4.ip_forward=1. This will enable it on the next reboot, but because we are impatient, activate it immediately with: 

sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"

need to share our Pi's internet connection to our devices connected over WiFi by the configuring a NAT between our wlan0 interface and our eth0 interface. We can do this using the following commands:

sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE  

sudo iptables -A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT 

sudo iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT  

we need these rules to be applied every time we reboot the Pi, so run  sudo sh -c "iptables-save > /etc/iptables.ipv4.nat" to save the rules to the file /etc/iptables.ipv4.nat. Now we need to run this after each reboot, so open the rc.local file with sudo nano /etc/rc.local and just above the line exit 0, add the following line:

" iptables-restore < /etc/iptables.ipv4.nat "

Now we are done with setting up our wifi on Raspberry Pi. This can be hosted using the following commands:

sudo service hostapd start

sudo service dnsmasq start

To check if we have got everything configured correctly reboot with “sudo reboot”

References:

• https://frillip.com/using-your-raspberry-pi-3-as-a-wifi-access-point-with-hostapd/