So after attending the 2 meet-ups for IOT-Pune. I got a Raspberry Pi and decided to play around with it a little bit. The following post will walk you through the steps needed to turn on/off a light bulb.
Things needed
1. Raspberry Pi
2. Relay switch
3. light bulb with wire to plug into main power supply
Lets us start!!!
- sudo apt-get install python-dev python-setuptools
- sudo pip install django
- django-admin.py startproject mysite
- cd mysite/
- django-admin.py startapp ledblink
- cd mysite
- open file named setting.py and add the ledblink app in the INSTALLED_APPS so that it looks like this
INSTALLED_APPS = (
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'ledblink',
# Uncomment the next line to enable the admin:
'django.contrib.admin',
# Uncomment the next line to enable admin documentation:
# 'django.contrib.admindocs',
)
- add this to the templates dir make sure you add import os at the top of the page
TEMPLATE_DIRS = (
os.path.join(os.path.dirname(__file__), 'templates').replace('\\','/'),
# Put strings here, like "/home/html/django_templates" or "C:/www/django/templates".
# Always use forward slashes, even on Windows.
# Don't forget to use absolute paths, not relative paths.
)
- cd ledblink
- open the views.py file and change it to this
from django.shortcuts import render
from django.http import HttpResponse
import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BOARD)
GPIO.setup(18,GPIO.OUT)
def blinker(request):
if 'on' in request.POST:
GPIO.output(18,1)
elif 'off' in request.POST:
GPIO.output(18,0)
return render(request,'control_page.html')
- Let us add the template control pages so go ahead and create a templates directory in your ledblink app and add the following html code and name it control_page.html
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<form action="" method="post">{% csrf_token %}
<input type="submit" name="on" value="on" />
<input type="submit" name="off" value="off" />
</form>
</body>
</html>
- now let us create a url that links to this view. Goto the urls.py file in mysite directory cd ../mysite
from django.conf.urls import patterns, include, url
from ledblink.views import blinker
# Uncomment the next two lines to enable the admin:
# from django.contrib import admin
# admin.autodiscover()
urlpatterns = patterns('',
url(r'^ledblink/$',blinker),
# Examples:
# url(r'^$', 'mysite.views.home', name='home'),
# url(r'^mysite/', include('mysite.foo.urls')),
# Uncomment the admin/doc line below to enable admin documentation:
# url(r'^admin/doc/', include('django.contrib.admindocs.urls')),
# Uncomment the next line to enable the admin:
# url(r'^admin/', include(admin.site.urls)),
)
- Goto main folder of the project where the manage.py file is located and run the following command
sudo python manage.py runserver 192.168.0.106:8000
open up a web browser and type http://192.168.0.106:8000/ledblink/ in the address bar and you should have the following result
now lets get to the part where we connect every thing to the raspberry pi.
- Sorry I couldn't get a better picture even though Nishant suggested to take the book out. :P But yoy connect the 5V out of the Pi that is pin 2 to the positive on the relay . The ground pin 6 to the regative of the relay and finaly GPIO18 to the corresponding pin on the relay board.
- Plug the bulb in the main power supply. Go ahead and try turning on the bulb from the web Browser
