Raspberry Pi + Relay Board to turn on 220v bulb from python Web page

To play with 220V , we should be a little careful and need to take all precautions with testers to check to 220v supply. This experiment we need to have Raspberry Pi ( already we have) and Relay Board which actually drive the switch and break the ciruit based on the 7th Pin voltage in GPIO pin.

 

Programs which we are gointo use same the Pyhon program we used to blink the LED from Flask python webpage

http://naveendavisv.blogspot.in/2014/07/raspberry-pi-flask-python-web-page-to.html

 

 

Only difference we used the Raspberry Pi GPIO pins 5v(2nd pin),Ground(6th pin), 7th pin to drive the relay a shown in the pictures.

 

 

 

 

 

Raspberry Pi Flask python web page to control the LED

I was searching for how to control the LED from python web page program. I reached in Flask microframework. http://flask.pocoo.org/

http://en.wikipedia.org/wiki/Flask_%28web_framework%29

Flask is lightweight web application framework written in python and its very much suited for Raspberry Pi board.  Controlling the LED connectioned to GPIO pin 7 is easy ,through the python program written importing Flask.

Steps to control LED connected to Raspberry Pi through WebPage

Step1: install Flask in Raspberry Pi.Follow below steps

apt -get install python-pip

pip install Flask

http://flask.pocoo.org/docs/installation/m

Step2. Connect the LED to the GPIO pin 7 through 470ohm resister

Step3: Writing Programs in Python Flask

First you need to create a python program which actually rendor the html templates stored in the 'templates' directory.

1.Create a folder called 'pythonsites' in your home directory  and you can write gpio.py in that folder as below. Refer the Flask site for example programs 

http://flask.pocoo.org/

route() decorator is used to bind a function to a URL. refer http://flask.pocoo.org/docs/quickstart/#routing

3 functions we have written which are  light_on, light_off  & light_blink

We are going to keep 3 links in the html template ,those are Turn On, Turn Off, LED blink

2.Once you have written this program ,should create a folder called 'templates' and keep our html template.

folder path -

pi@raspberrypi ~/naveen/pythonsites/templates $

html page shows in the browser create as light.html

Web page using Flask:

Run gio.py program using python

sudo python gio.py

connect with port to raspberry as follows ,depends on your raspberrypi IP address.

 http://192.168.1.10:5000/

Raspberry Pi LED chain blinking program python