Raspberry-Pi

Content Layout
 Raspberry Pi
o Introduction
o Types & Specifications
o OS
o Architecture
o GPIO Pins
o Hardware & Connectivity
o Use of PI
 Wireless Display over Bluetooth using Pi and Android Phone
 Video
o Raspberry Pi based FM Transmitter
o Difference between Raspberry Pi & Arduino

What is Raspberry Pi?
Raspberry Pi is a single board computer which is the size as small as a credit card.
 Developed by Raspberry Pi foundation in UK
 Costs around US$25 to $35
KEY FEATURES
• Connect to the TV via HDMI interface
• For learning programming
• Act as a media centre for video playback or gaming functions
 The Raspberry Pi measures 85.60mm x 56mm x 21mm (or roughly 3.37″ x 2.21″ x 0.83″) & It weighs 45g

Types& Specification Of Raspberry Pi
There are two types of Raspberry Pi :
Model A Model B

OPERATING SYSTEM USED IN RASPBERRY PI
 First you have to write it to a suitable (2GB or 4GB) SD card using the UNIX tool dd.
Windows users can use Win32 Disk Imager.
 Install NOOBS in your primary PC
 List of OS
Raspbian “wheezy”
OpenELEC
Occidentalis v0.2
Pidora
RaspBMC
RISC OS
Arch
Linux based OS

PINSLAYOUT
• 17 GPIOpins
• most have alternated functions
• two pins for UART; two for I2C; six for
SPI
• All 17 pins can be GPIO (i.e., INPUT or
OUTPUT)
• all support interrupts
• internal pull-ups & pull-downs for each
pin
•Pins are 3.3V not 5V like on the Arduino
•They are connected directly to the
Broadcom chip
•Sending 5V to a pin may kill the Pi
•Maximum permitted current draw from a
3.3V pin is 50mA

Diagram includes BCM GPIO references (GPIO.BCM), common
functions, WiringPi pin references, and Pin numbers (GPIO.BOARD).
The Bigger Picture

Hardware & Connectivity inside the Pi
COMPONENTSOFA RASPBERRY PI

POWER
5v micro
USB
connector
(Similar to the one on a lot of mobile phones!)

A/V (AUDIO/VIDEO)
HDMI Audio & Video
(works with modern TVs and DVI monitors)

A/V (AUDIO/VIDEO)
RCA Video
(works with
most older
TVs)
HDMI Audio & Video

A/V (AUDIO/VIDEO)
RCA Video
(works with
most older
TVs)
HDMI Audio & Video
3.5mm Audio
Standard
headphone
socket

CONNECTIVITY
2 x USB 2.0
ports

CONNECTIVITY
2 x USB 2.0
ports
10/100Mb
Ethernet

CONECTIVITY
2 x USB 2.0
ports
10/100Mb
Ethernet
GPIO
(General
Purpose
Input &
Output)

INTERNALS
SOC (System On a Chip)
Broadcom BCM2835 700Mhz & 256Mb / 512Mb RAM

INTERNALS
LAN Controller

INTERNALS
JTAG
(debug ports)
LAN Controller

INTERNALS
JTAG
(debug ports)
LAN Controller
CSI
(camera interface)

INTERNALS
JTAG
(debug ports)
LAN
Controller
CSI
(camera interface)
DSI
(display interface)

STORAGE
SD Card Slot
(supports SD cards up to 32GB)

WIRELESSDISPLAY OVER BLUETOOTH
USING PI AND ANDROID PHONE

PROJECT OVERVIEW
 Goal is to build a system using Raspberry Pi and an Android phone to
get the wireless display over Bluetooth and setup a Virtual Network
connection between them
 The basic idea is to set up Bluetooth networking with the Pi, and use
SDL VNC viewer to display the X screen on the Android device
 Virtual NetworkComputing (VNC) is a graphical desktop sharing
system that uses the Remote Frame Buffer protocol (RFB) to remotely
control another computer. It transmits the keyboard and mouse events
from one computer to another, relaying the graphical screen updates
back in the other direction, over a network.

MOTIVATION
 The basic idea of connecting a raspberry pi and an android
over Bluetooth and VNC
 Give usera flexibility to access and workremotely overthe phone
 Can help save and store data over the pi and phone. The
phone can be accessed completely over the Raspberry Pi
 The Raspberry Pi is a pretty powerful device, but much of its
benefits come when it's connected to the Internet. If we want
to utilize the Pi for mobility, we should try this method of
tethering it to our smartphones to get it online anywhere we
have mobile data

SYSTEM ARCHITECTURESystem Architecture:
An overall view of the system is as below:
Ping
On Pi Android Phone
Bluetooth network setup
UtilityVNC Set-up

BLUETOOTH NETWORK SETUP
 The Raspberry pi is not equipped with the built in Bluetooth,
so we need to follow the below steps:
 Bluetooth dongle (We used version 2.0)
 Install drivers
 Commands on the command editor of pi to scan the devices
over Bluetooth. This is needed only for first time
 Connect

VNC SETUPFOR RASPBERRY PI
 Using commands, we installed
TightVNCServer over Raspberry Pi
 Set the pixel format and
geometry settings as for the
Android display screen
 Install client over android
 Connect to Raspberry pi

LEARNING
 Basic Raspberry Pi setup and connection
 Connecting Raspberry Pi and android phone over Bluetooth and access
the data and folders of Android from pi
 Establishing the Virtual Network connection between the Pi and Android
 This enables the users to remotely access the Raspberry pi system over a phone
 Once completely installed, the Pi should automatically mount and
connect to our mobile device when we plug it in, without having to fiddle
around in the command
 Can be enhanced and improved for future works like live
demonstrations, programming and learning

Controlling a Servo with the Pi
• Controlling the servos requires PWM, aka Pulse Width Modulation
– The Arduino program has complete control of the microcontroller
• when it is running loop() nothing else can use the CPU
– Except for interrupt handlers written as part of the Arduino
program
– On the Raspberry Pi, your program runs within a Linux OS
• The Linux OS may switch to running another program!
– But you can change your program’s scheduling priority
• Some ways of getting the Pi to give the impression that it is a real time
system and to do PWM ‘properly’:

Connect a Parallax Servo
Servo Connector:
Black – Pi’s ground
Red – Pi’s 5V
White – signal on GPIO 17
Image credit: http://www.parallax.com/
NOTE: For a single small servo you can take the 5 volts for it from the Pi header,
but doing anything non-trivial with four servos connected pulls the 5 volts down
far enough to crash the Pi

Using WiringPi’s servo example
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <wiringPi.h>
#include <softServo.h>
int main () {
if (wiringPiSetup () == -1) { // setup to use Wiring pin numbers
fprintf (stdout, "oops: %sn", strerror (errno)) ;
return 1 ;
}
softServoSetup (0, 1, 2, 3, 4, 5, 6, 7) ; // wiringPi pin numbers
for (;;) {
softServoWrite (0, 0) ; // wiringPi pin 0 is BCM_GPIO 17
delay (1000) ;
softServoWrite (0, 500) ;
delay (1000);
softServoWrite (0, 1000) ;
delay (1000);
}

Running servo.c
• To compile: gcc -Wall -o servo servo.c
wiringPi/wiringPi/softServo.c  compile softServo.c
-IwiringPi/wiringPi  path to softServo.c
-lwiringPi  include wiring library
• To run: sudo ./servo
• Calling softServoWrite () ;
– The 1st
input is the pin number
– The 2nd
input refers to the number of microseconds of the pulse.
• An input of 0 produces a 1000uSec (1mSec) pulse (hard left)
• An input of 1000 produces a 2000uSec (2mSec) pulse (hard right)
• An input of 500 produces a 1500uSec (1.5 mSec) pulse (stop)

Raspberry-Pi

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