What is a Raspberry pi ?

The Raspberry Pi is a series of credit card-sized single-board computers. It can be used to build hardware along with software system . It essentially acts like a mini computer where we can install our programs and work on them pretty much like a regular computer . However the applications of Rpi is really diversifies from making robots to kiosks , surveillance system to remote control agents etc .

Yes the new model B+ is out yet I have an old B model and I am trying ot most of the things using it before making the investment of purchasing a  new one .

(images from : http://www.adafruit.com/products/998)

Configuration :

• The design is based around a Broadcom BCM2835 SoC, which includes an ARM1176JZF-S 700 MHz processor, VideoCore IV GPU, and 512 Megabytes of RAM.
• The design does not include a built-in hard disk or solid-state drive, instead relying on an SD card for booting and long-term storage.
• This board is intended to run Linux kernel based operating systems.
• Generic USB keyboards and mice are compatible with it .
• It does not come with a real-time clock, so an OS must use a network time server, or ask the user for time information at boot time to get access to time and date info for file time and date stamping. However a real time clock (such as the DS1307) with battery backup can be easily added via the I2C interface.

Physical architecture :

Pin Model :

Rpi model B startup

Requirements for boot

1. Power supply
2. HDMI cable to connect to HDMI tv or HDMI to VGA adapterto connect to monitor
3. power charger ( micro USB same as phone )
4. SD card upto 8 GB ( in case its a micro SD card then SD card adpater as well)
5. monitor
6. keyboard
7. mouse
8. internet through ethernet
9. ethernet wire

Steps:

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 RPI model B to LED glow using timers in python

Aim :

First time booting Raspbian on Raspberry pi Model B . Connecting it to LED ( series with resistor ) and controlling the on -off process using timer logic written in python .

Requirements :

1. Rs(RaspberryPi)
2. Power supply
3. Ethernet wire(3m)
4. SDcard or micro SD card with adpater
5. Breadboard
6. LED(7)
7. resistors(1k )(7)
8. button
9. breadboard wires

Steps :

1. Manual ON and OFF of LED on Rpi GPIO

To manually make the LED turn ON and OFF ,  make a serial connection of two GPIO pins with a LED  and resistor ( shown in the picture )

• Open terminal and sudo su  to :/home/pi#
• #echo25>/sys/class/gpio/export
• File manager -> /home/pi -> sys -> class ->gpio -> gpiochip0 -> device -> gpio ->gpio25 , Change directory to this location
• #cd /sys/class/gpio/gpiochip0/device/gpio/gpio25
• List all files , with gpio#ls

To give output to LED through the pin 25 :

• echo out>direction ( set this pin as output)
• To tuen ON the LED , write 1 to the value of pin echo 1> value

To take input through pin 24 through a button

• connect button to pin 24 of Rpi as earlier
• echo in >direction
• see the changes on pressing the button on cat value

2. GPIO control with WiringPi library

• Install git , sudo apt-get innstall git-core
• Get the sourcecode with :sudo git clone git://git.drogon.net/wiringpi
• cd wiringPi
• ./build
• $gpio -v
• $gpio readall

To turn ON or OFF the first LED wiring pin 0 , set the pin as an output  -> gpio mode 0 out

• To turn ON LED  -> $gpio write 0 1
• To turn OFF  -> $gpio write 0 0

To read from a digital switch on wiringPin no

• $ gpio read 0

Applications:

1.  Timer based control

Following are the steps to make and execute a LED  control using timers in python .

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 Machine control through RPi via Mobile app on Internet

Aim :

Controlling a machine via Rpi hub connected to internet . Users can control machine behavior through a web page or mobile app .

Steps:

1. Install Raspbian wheezy ( details of installation are provided in the 1fisrt application on this page )

2. Get win32 Disk-manager 0.25 and dump into raspberry

3. Connect the Rpi via Ethernet wire to internet router . Find IP address of Rpi client by checking the router default console .

4. Connect the Rpi to remote machine

For Linux remote machine OS –Install tightVNC server

• ssh  raspberrypi_username@ipaddress
• sudo apt-get updates
• sudo apt-get install tightvncserver
• During installation supply a username and password example , username pi  , password altanai.

The viewer for VNC could be Remmina VNC viewer on linux

• Incoming VNC server .
• Enter username and password

For Windows  remote machine OS –Install putty

• Enter Rpi_ip:port
• login as pi given password  for example altanai

5. For the webpage

• Install a web server  :sudo apt-get install apache2 php5 libapache2-mod-php5
• transfer the web page for machine control  to Rpi inside /var/www
• index.phpo :  <?php phpinfo(); ?>
• ctrl+ o to save , ctrl + x to exit
• change permission fr user pi :  chown -R pi /var/www
• test the webpage at http://rpi_address

6. For the android app

7. To control real machine like fan , tubelight , washing machine  , connect the output of Rpi to relay.

8. To control the machines from anywhere on the internet , this page need to be on public DNS . There fore host the website on public server like amazon Ec2 instance .

Github Repo for Rpi setup

https://github.com/altanai/Ramudroid/tree/master/robot_controller_rpi_setup

Github project page

http://altanai.github.io/Ramudroid/

Demo video

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Ref :

1. http://www.adafruit.com/products/998
2. http://www.raspberrypi.org/
3. http://www.instructables.com/id/Simple-and-intuitive-web-interface-for-your-Raspbe/

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