GPIO_RaspberryPi

#9/3,Shree Lakshmi complex,2nd

Floor,Opp,To Vivekananda Park,Girinagar,Bangalore-560085.www.tenettech.com

2014

Author: P N KIRAN

Email ID:[email protected]

Getting Started with Raspberry Pi and interfacing with an Universal GPIO board



Introduction:

This easy step by step guide will help you set up your raspberry pi and get started

Hardware requriment:

Raspberry pi

8GB Micro sd card

Software requriment :

Raspbian Debian Wheezy

Raspberry pi :

The Raspberry Pi is a credit-card sized computer that plugs into your TV and a keyboard. It is a

capable little computer which can be used in electronics projects, and for many of the things that your

desktop PC does, like spreadsheets, word-processing and games. It also plays high-definition video.

We want to see it being used by kids all over the world to learn how computers work, how to

manipulate the electronic world around them, and how to program.. for more info please visit the link

click here.

Raspbian: The “officially recommended” official distribution from the Foundation,based on Debian.

Note that raspbian.org is a community site, not operated by the Foundation. If you’re looking for the

official distribution, visit the downloads page at raspberrypi.org.

Getting Started

Step 1:

Download Raspberry pi official Operating system Raspbian . For downloading this

OS please visit the link click here

Step 2:

Prepare your SD Card:

Plug an micro sd card in to an card reader and plug in to an pc format this micro sd

card using sd formater. For downloading this sd formater please visit the link click

here

SD card setup (copying the image to an SD card using on windows)

o Extract the image file 2013-09-09-wheezy-raspbian.img from the downloaded

.zip file.

o Write an downloaded OS in to an micro SD card using win32 disk imager .for

downloading this win32 disk imager please click here.

http://www.raspberrypi.org/

http://www.raspberrypi.org/downloads/

https://www.sdcard.org/downloads/formatter_4/eula_windows/

https://www.sdcard.org/downloads/formatter_4/eula_windows/

http://sourceforge.net/projects/win32diskimager/files/latest/download



o Extract the executable from the zip file and run the Win32DiskImager utility.

You may need to run the utility as Administrator

o Insert the SD card into your SD card reader and check what drive letter it was

assigned.

o You can easily see the drive letter (for example F:) by looking in the left

column of Windows Explorer.

o If the card is not new, you should format it; otherwise Win32DiskImager may

hang.

o Select the 2013-09-09-wheezy-raspbian.img image file you extracted earlier

o Select the drive letter of the SD card in the device box.

o Be careful to select the correct drive; if you get the wrong one you can destroy

your computer's hard disk! .

o Click Write

o And wait for the write to complete.



Step 3 :

Prepare and Connect

Insert your prepared micro SD Card in to an Raspberry pi Micro SD card slot .

Plug the HDMI output into your TV or monitor. Make sure your monitor is on.

Plug in the power supply. In general, try to make sure everything else is

hooked up before connecting the power.

Turn raspberry pi board on by plugging the micro usb Power cabel(5v,1A dc)

Step 4 :

Then Raspberry Pi, power it on, and it should boot up. There is an option in the configure script

that comes up to expand the partitions to use all of the SD card if you have used one larger than

8GB..

It will ask login id and password

start the graphical interface:

o raspberrypi login: pi

o Password: raspberry

o pi@raspberrypi ~ $ startx



Interfacing 8 LED’s with Raspberry Pi:

Let’s start with a quick introduction to the Raspberry Pi GPIO (General Purpose Input Output).There

are 26 GPIO pins in total including 3.3V (2), 5V (2) and GND (4). Raspberry Pi can set to HIGH

(taking the value 1) by connecting it to a voltage supply, or set to LOW (taking the value 0) by

connecting it to the ground and treat it as an output or it can detect the pin and treat as an input.

Raspberry Pi GPIO PIN OUT

Hardware:

Raspberry Pi Model B

Power Cable

LED – 8

Breadboard

Jumper wires—Male to Female

If you do not have any of these components, make and online order from the following link.

www.tenettech.com

Connections:

http://www.tenettech.com/



Raspberry Pi :

GPIO Board:



Pin Configurations:

Pi GPIO BOARD

3 L1

5 L2

7 L3

8 L4

10 L5

11 L6

12 L7

13 L8

2 VCC

6 GND



Code:

import RPi.GPIO as GPIO

from time import sleep

GPIO.setmode(GPIO.BOARD)

from array import *

a = array('i',[3,5,7,8,10,11,12,13])

for i in range(0,8):

GPIO.setup(a[i],GPIO.OUT)

GPIO.output(a[i],GPIO.LOW)

sleep(0.04)

while 1:


GPIO.output(a[i],GPIO.HIGH)

sleep(0.04)

GPIO.output(a[i],GPIO.LOW)

sleep(0.04)


GPIO.output(a[7-i],GPIO.HIGH)

sleep(0.04)

GPIO.output(a[7-i],GPIO.LOW)

sleep(0.04)

Open Your Leafpad or nano editor from your LXterminal:

sudo leafpad filename.py

Type the above code in the editor and save the file. To run the code type the following command.

Once started running the programming led blinks from left to right and right to left.

sudo python filename.py



Interfacing Push button with Raspberry Pi:

Push Button is a simple switch mechanism for controlling some aspect of a machine or a

process.Pushbutton is a component that connects two points in a circuit when you press it. For

example turns on an LED when you press the button.

Raspberry Pi Pinout:







Hardware:


Power Cable

Push Button – 4


Connections:

Raspberry Pi:



GPIO BOARD :

Pin Configurations:

Pi GPIO BOARD

8 SW1

10 SW2

11 SW3

12 SW4

2 VCC

6 GND



Code:


GPIO.setmode(GPIO.BOARD)

GPIO.setup(8,GPIO.IN)




while True:

if GPIO.input(8):

print “First button has been pressed”

elif GPIO.input(10):

print “Second button has been pressed”

elif GPIO.input(11):

print “Third button has been pressed”

else:

print “Fourth button has been pressed”




Once




Interfacing 7 SEGMENT with Raspberry Pi 7 SEGMENT:

A seven-segment display (SSD), or seven-segment indicator, is a form of electronic display device

for displaying decimal numerals that is an alternative to the more complex dot matrix displays.

Application Areas:

Digital Clocks,

Electronic meters

Electronic Devices for Displaying Numerical Informations.






Hardware:


Power Cable

7 Segment

Jumper wires—Female to Female



Connections:

GPIO BOARD:



Pin configurations:

Pi GPIO BOARD

22 A

17 B

27 C

4 D

18 E

23 F

24 G

25 DP

CODE:


import time

GPIO.setmode (GPIO.BCM)

GPIO.setup(22, GPIO.OUT)








while True:

GPIO.output(4, GPIO.LOW)

time.sleep(.5)


time.sleep(.5)




time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)

GPIO.output(24, GPIO.HIGH)

time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)


time.sleep(.5)




time.sleep(.5)


time.sleep(.5)


time.sleep(.5)



Type the above code in the editor and save the file. To run the code type the following

command. Once started running the programming led blinks from left to right and right to left.




Interfacing Buzzer with Raspberry Pi:

Buzzer:

Buzzer or Beeper is an audio signaling device which may be mechanical, electromechanical

or piezoelectric.

Application Areas:

Alarm Device

Timer

Microwave Ovens

Household Appliances






Hardware:


Power Cable

Buzzer

Breadboard


If you do not have any of these components, make and online order from the following link.

www.tenettech.com

http://www.tenettech.com/



Circuit Diagram

Code:


from time import sleep

GPIO.setmode (GPIO.BOARD)

GPIO.setup(12,GPIO.OUT)

while 1:

GPIO.output(12,GPIO.HIGH)

sleep(1)

GPIO.output(12,GPIO.LOW)

sleep(1)




Once started running the programming led blinks from left to right and right to left.




Interfacing Potentiometer with Raspberry Pi

Potentiometer:

A potentiometer is a simple knob that provides a variable resistance. By turning the shaft of the

potentiometer, we change the amount of resistance on either side of the wiper which is connected to

the center pin of the potentiometer.

Application Areas:

Audio control

Television

Motion Control






Hardware:


Power Cable

POT




Connections:

Raspberry Pi:



GPIO BOARD:

CODE:


import time

GPIO.setmode(GPIO.BCM)

Input_A=18

Input_B=23

GPIO.setup (input_A, GPIO.IN,pull_up_down=GPIO.PUD_UP)

GPIO.setup (input_B, GPIO.IN,pull_up_down=GPIO.PUD_UP)

old_a=True

old_b=True

def get_encoder_turn():

global old_a,old_b

result=0

new_a = GPIO.input(input_A)

new_b = GPIO.input(input_B)

if new_a !=old_a or new_b != old_b:

if old_a == 0 and new_b != old_b:

result = (old_b * 2 ==1:

elif old_b == 0 and new_b ==1:

result = (old_a * 2 - 1)

old_a,old_b = new_a, new_b

time.sleep(0.001)

return result



x=0

while True:

change = get_encoder_turn()

if change !==0:

x = x + change

print (x)



Type the above code in the editor and save the file. To run the code type the following

command. Once started running the programming led blinks from left to right and right to left.


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GPIO_RaspberryPi

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