DHT11 connected to Raspberry Pi to measure Room Temperature & Humidity

As always the difficult part while interfacing a device especially sensors is  the signal decoding. I always felt difficult to understand the specifications of a electronic device.

DHT11 decoding code and instructions I got from the below link 

http://www.uugear.com/portfolio/dht11-humidity-temperature-sensor-module/

Raspberry Pi and DHT11 connection Diagram:

I just followed the instructions and finially I measured my room temperature and humidity.

Ordered a DHT11 to connect with Raspberry Pi

Today I have ordered DHT11 in ebay.Just need to do some experiment with GPIO pins on Raspberry Pi in input mode.

DHT11 Temperature and Humidity Sensor features a calibrated digital signal output with the temperature and humidity sensor complex. Its technology ensures the high reliability and excellent long-term stability. A high-performance 8-bit microcontroller is connected. This sensor includes a resistive element and a sense of wet NTC temperature measuring devices. It has excellent quality, fast response, anti-interference ability and high cost performance advantages

DHT11 timing diagram:

DHT11 connection Diagram:

Waiting for it to come.................................

Object Game in Raspberry Pi using Pygame

It is easy to build falling balls in Pygame and try to use the sleep function to delay the balls.

Video in youtube:

Remote Desktop to Raspberry Pi from Windows 7

How to log in as Remote Desktop to Raspberry Pi from Windows 7 PC

In order to remote log in RaspberryPi , we have to install xrdp. Following steps can be used for install the software .

Install the xrdp software in  Raspberry Pi

sudo apt-get install xrdp

in order to know the status of xrdp , we can use the following command

/etc/init.d/xrdp status

For starting , use the below command

/etc/init.d/xrdp start

For stoping , /etc/init.d/xrdp stop

make sure your xrdp running in Raspberry Pi

In windows 7 PC, we will be getting the 'Remote Desktop Connection' from the start menu.

Enter the IP address of your raspberry pi in the computer field, and connect.

Raspberry Pi connecting with Joystick in Pygame

Programming Joystick gaming with Raspberry pi

Install joystick using the command below:

sudo apt-get install joystick

after installation you can find file js0 in the directory:

/dev/input/

sudo cat /dev/input/js0

sudo cat /dev/input/js0 | hexdump

Pygame program to read joystick buttons

joystick = pg.joystick.Joystick(0)
joystick.init()

pg.joystick.joystick(0) returns the joystick object and init() function initialize the device values.

 button1 = joystick.get_button(0) retrives the button(0)

below program includes functions to read the keyboard input and mouse inputs. 

Pygame Joystick program:

import pygame as pg
# initialize pygame
pg.init()

# use an image you have (.bmp  .jpg  .png  .gif)
image_file = "ball"
# RGB color tuple for screen background
black = (0,0,0)
# screen width and height
sw = 640
sh = 480
# create a screen
screen = pg.display.set_mode((sw, sh))
# give the screen a title
pg.display.set_caption('image follows mouse click position')
# load an image
# convert() unifies the pixel format for faster blit
image = pg.image.load(image_file).convert()
# get the rectangle the image occupies
# rec(x, y, w, h)
start_rect = image.get_rect()
image_rect = start_rect
running = True
joystick = pg.joystick.Joystick(0)
joystick.init()
while running:
    event = pg.event.poll()
    keyinput = pg.key.get_pressed()
    button3 = joystick.get_button(2)
    button1 = joystick.get_button(0)
    # exit on corner 'x' click or escape key press
    if keyinput[pg.K_ESCAPE]:
        raise SystemExit
    elif event.type == pg.QUIT:
        running = False
    elif keyinput[pg.K_LEFT]:
        image_rect.left = image_rect.left - 1
        image_rect.right = image_rect.right-1
        print "corner coordinates --> (%d, %d, %d, %d)" % \
            (image_rect.left, image_rect.top, image_rect.right,
            image_rect.bottom)

        screen.fill(black)

    elif keyinput[pg.K_RIGHT]:
        image_rect.left = image_rect.left + 1
        image_rect.right = image_rect.right+1
        screen.fill(black)
        screen.blit(image, image_rect)
        pg.display.flip()
    elif keyinput[pg.K_DOWN]:
        image_rect.top = image_rect.top + 1
        image_rect.bottom = image_rect.bottom+1
        screen.fill(black)
        screen.blit(image, image_rect)
        pg.display.flip()

    elif keyinput[pg.K_UP]:
        image_rect.top = image_rect.top - 1
        image_rect.bottom = image_rect.bottom-1
        screen.fill(black)
        screen.blit(image, image_rect)
        pg.display.flip()

    elif button3:
        print("Joystick up pressed")
        image_rect.top = image_rect.top - 1
        image_rect.bottom = image_rect.bottom-1
        screen.fill(black)
        screen.blit(image, image_rect)
        pg.display.flip()

    elif button1:
        print("Joystick down pressed")
        image_rect.top = image_rect.top + 1
        image_rect.bottom = image_rect.bottom+1
        screen.fill(black)
        screen.blit(image, image_rect)
        pg.display.flip()
 

Pygame built with Raspberry Pi & Joystick 

Trying owncloud in Raspberry Pi

I am trying owncloud in Raspberry pi following the instructions .  succeeded to lauch owncloud in Raspberry.


install it using following steps

sudo /etc/init.d/php5-fpm restart
sudo /etc/init.d/nginx restart



type in browser :  get ip address from ifconfig command

https://192.168.1.10/owncloud

PyGame in Raspberry using Mouse and Keyboard

I was actually trying to write a simple program which reads the input from keyboard and mouse to Pygame python program. when I searched , found its easy and within a few lines of code in Python we can able to control the movements of an image object in python.

The function image.load can load the image to the screen.

image.get.rect() get the rectangle coordinates of the image position. 

Event 'pg.key.get_pressed' reads the key press events and 'ÍF' clause checks which key has been given as inputs in the below program.

The same mouse click event also capturing inside the while loop which runs till the variable 'running' is true.

Based on the key inputs the rectangle image object position coordinates were changed to make movements to the image.

Raspberry Pi Pygame to control Image movements through External Keyboard or mouse