How to Control an LED with Raspberry Pi Webserver using Apache

Controlling an LED with Raspberry Pi Webserver using Apache

In this tutorial, we will install Apache web server in Raspberry Pi to control the LED from a webpage that can be accessed from anywhere over the internet. This is a basic tutorial with minimum features and it can be further modified to use this method in IoT-based home automation, remote control automation, robotics, etc.

Here we control an LED connected to Raspberry Pi by using Apache web server. For this, we create an HTML/php web page which has two buttons - one for turning on the LED and the second for turning off the LED.

 

Components Required

  1. Raspberry pi board (With Raspbian operating system)
  2. LED
  3. 250-ohm resistor
  4. Jumper Wires

 

An SSH client (Putty) is used to connect the Raspberry pi using a Laptop or computer. For this, the raspberry pi needs to be connected to a network via LAN or Wi-Fi. If you have a separate monitor for your raspberry pi, then it's better to connect raspberry pi with the monitor and you don’t have to use any SSH client.

 

Controlling LED using Raspberry Pi Webserver

Step 1: Connections

Raspberry Pi LED Connection Circuit

The connections in this project are quite simple - the positive pin of LED is connected to GPIO 27 pin and the negative pin to a 270 ohm resistor, the other side of which is connected to GND pin.

 

Step 2: Installing WiringPi Library

WiringPi is a PIN-based GPIO access library written in C for the BCM2835, BCM2836, and BCM2837 SoC devices used in all Raspberry Pi versions. It’s released under the GNU LGPLv3 license and is usable from C, C++, and RTB (BASIC) as well as many other languages with suitable wrappers.

1. First we will update our Pi with the latest versions of Raspbian using the command:

sudo apt-get update

 

2. Now we will install git by using this command:

sudo apt-get install git-core

 

3. Now obtain WiringPi using git by this command:

git clone git://git.drogon.net/wiringPi

 

4. Then install WiringPi library using:

cd wiringP./build

 

Step 3: Installing a Web Server

Apache is a very popular webserver, designed to create web servers that have the ability to host one or more HTTP-based websites. Apache Web Server can be enhanced by manipulating the code base or adding multiple extensions/add-ons. In our project, we are using an HTTP server and its PHP extension.

To Install Apache web server, we will use the following commands:

First, update the available packages:

sudo apt-get update

 

Now, install the apache2 package by using this command in the terminal:

sudo apt-get install apache2 -y

 

To test the web server whether it is working or not, go to your browser and type the Pi’s IP address in the tab.

To find the Pi's IP address, type ifconfig at the command line.

By default, Apache puts a test HTML file in the web folder. This default web page is served when you browse to http://192.168.1.31 (whatever the Pi's IP address is) from another computer on the network.

Browse to the default web page either on the Pi or from another computer on the network and you will see the following:

Apache2 Webserver

This means the Apache web server is working.

 

Now we will see how to change the default web page with your own HTML page

This default web page is just an HTML file on the filesystem. It is located at var/www/html/index.html.

Navigate to this directory in a terminal window and have a look at what's inside:

cd  var/www/html
ls -al
This will show you:
total 12
drwxr-xr-x  2 root root 4096 Jan  8 01:29 .
drwxr-xr-x 12 root root 4096 Jan  8 01:28 ..
-rw-r--r--  1 root root  177 Jan  8 01:29 index.html

 

This shows that by default there is one file in /var/www/html/ called index.html and it is owned by the root user. To edit the file, you need to change its ownership to your own username. Change the owner of the file using:

Sudo chown pi: index.html.

 

You can now try editing this file and then refresh the browser to see the web page change.

 

Install PHP in Raspberry Pi  

Now if we want to use PHP code along with HTML, then we have to further install the PHP extension in Raspberry pi. Using PHP code, we can create shell commands to control the LED from the PHP script.

To allow the Apache server to edit PHP files, we will install the latest version of PHP and the PHP module for Apache. Use the following command in terminal to install these:

sudo apt-get install php libapache2-mod-php -y

 

Now remove the default index.html file:

sudo rm index.html

 

And create your own index.php file:

sudo nano index.php

 

Now enter the below code in index.php to test the PHP installation.

<?php phpinfo(); ?>

 

Save it by pressing CTRL + X and the ‘y’ and enter. Now refresh the webpage in your browser, you will see a long page with lots of information about PHP. This shows that the PHP extension is installed properly. If you have any problem with the pages or if the pages do not appear, try reinstalling the apache server and its PHP extension.

 

Step 5: Start Coding for controlling GPIO pin using this Raspberry Pi Webserver

Now delete the previous code in index.php (<?php phpinfo(); ?>) file and insert below PHP code to control GPIO pins inside body of HTML code.

Below is the complete code for creating two buttons to turn on and off the LED connected to Raspberry Pi.

<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Raspberry Pi WiFi Controlled LED</title>
</head>
       <body>
       <center><h1>Control LED using Raspberry Pi Webserver</h1>      
         <form method="get" action="index.php">                
            <input type="submit" style = "font-size: 14 pt" value="OFF" name="off">
            <input type="submit" style = "font-size: 14 pt" value="ON" name="on">
         </form>​​​
                         </center>
<?php
    shell_exec("/usr/local/bin/gpio -g mode 27 out");
    if(isset($_GET['off']))
        {
                        echo "LED is off";
                        shell_exec("/usr/local/bin/gpio -g write 27 0");
        }
            else if(isset($_GET['on']))
            {
                        echo "LED is on";
                        shell_exec("/usr/local/bin/gpio -g write 27 1");
            }
?>
   </body>
</html>

Raspberry Pi Webserver

In the above code there is a PHP script which checks which button is pressed by using below code and then turns on and off the LED accordingly.

<?php
    shell_exec("/usr/local/bin/gpio -g mode 27 out");
    if(isset($_GET['off']))
        {
                        echo "LED is off";
                        shell_exec("/usr/local/bin/gpio -g write 27 0");
        }
            else if(isset($_GET['on']))
            {
                        echo "LED is on";
                        shell_exec("/usr/local/bin/gpio -g write 27 1");
            }
?>

 

Here we have used shell_exec() command in php code, this command is used to run the shell command from the PHP script. Learn more about shell_exec here. If you run the command inside shell_exec directly form the terminal of Raspberry pi, you can directly make GPIO pin 27 low or high. Below are two commands to test the LED directly from terminal.

/usr/local/bin/gpio -g write 27 0
/usr/local/bin/gpio -g write 27 1

 

After completing this, run the code in your browser by typing the IP address of raspberry pi in the browser. You will see 2 buttons - ON, OFF to control your LED by clicking these buttons.

 

I hope you liked this article. You can also check out our other Internet of Things projects.

759 Comments

I got the webserver running the buttons refresh correctly.
I have an LED connected to pin 16(on the pi) or 24 (mapped) and I can control it using a python script.
When I press the button in browser the state changes text shows correctly but LED doesn't light up.
When I try username@raspberrypi:~$ shell_exec() /usr/local/bin/gpio -g write 24 1 it gives:
-bash: syntax error near unexpected token `/usr/local/bin/gpio'

Does anyone know why this happens?

Weight Vest Training: Benefits of Weighted Vests | iamazonsurmountwayweightedvest_2021 What are the best weighted vests for CrossFit, running, hiking, and walking? ... Best Budget Weighted Vest for Home Gym Training And Calisthenics.Using weighted vests or backpacks to increase intensity to a standard flat.This Weighted Vest To Let You Increase The Difficulty Of Your Wods And Bodyweight Exercises.his is simply hiking with additional weight other than your body weight.

Undeniably consider that that you stated. Your favorite reason appeared
to be at the net the easiest factor to take into accout
of. I say to you, I definitely get annoyed even as people consider issues that they
just do not realize about. You managed to hit the nail upon the top as well as defined out the whole thing without having side-effects , other folks could take a signal.
Will probably be back to get more. Thanks

Hey there just wanted to give you a quick heads up.
The words in your post seem to be running off the screen in Chrome.
I'm not sure if this is a format issue or something to
do with browser compatibility but I thought I'd post to
let you know. The design look great though! Hope you get the problem fixed soon. Thanks

I don't even understand how I stopped up here, but I believed this submit was good.
I don't understand who you are but definitely you are going to a famous blogger in case you aren't already.
Cheers!

I know this if off topic but I'm looking into
starting my own weblog and was curious what all is required to get setup?
I'm assuming having a blog like yours would cost a pretty penny?

I'm not very internet savvy so I'm not 100% sure. Any tips or advice would be
greatly appreciated. Thanks

Magnificent items from you, man. I have remember your stuff previous to and you're simply too magnificent.
I really like what you have acquired here, certainly like what you're stating and the best way by which you say it.
You are making it entertaining and you still care for to stay it wise.
I can't wait to learn much more from you. This is actually
a tremendous website.

Having read this I believed it was really enlightening. I appreciate you taking
the time and energy to put this informative article together.
I once again find myself personally spending a lot of time both reading and posting comments.
But so what, it was still worth it!

Nice post. I used to be checking constantly this blog and I'm impressed!
Very helpful information particularly the last phase :) I care for such info a lot.
I used to be looking for this particular information for a
long time. Thank you and best of luck.

We are a group of volunteers and opening a
new scheme in our community. Your site provided us with valuable information to work on. You have done
an impressive job and our whole community will be grateful to you.

Thanks for ones marvelous posting! I seriously enjoyed reading it, you can be a great author.I will ensure that I bookmark your blog
and will come back later on. I want to encourage that you continue your great job,
have a nice holiday weekend!

I'm not sure why but this weblog is loading incredibly slow for me.

Is anyone else having this problem or is it a problem on my end?

I'll check back later and see if the problem still exists.

I think this is one of the such a lot vital information for me.

And i'm glad reading your article. But wanna statement on few basic
things, The website taste is great, the articles is in point of fact excellent : D.

Excellent process, cheers

This is the right blog for anybody who wants to find out about this
topic. You realize so much its almost tough to argue with you (not that I
personally will need to…HaHa). You certainly put
a new spin on a topic that's been written about for
decades. Wonderful stuff, just excellent!

Fantastic website you have here but I was curious
if you knew of any community forums that cover the
same topics discussed in this article? I'd really love to be a part of group where I
can get comments from other knowledgeable individuals that share the same interest.
If you have any recommendations, please let me know. Thanks a lot!

Having read this I thought it was rather informative.

I appreciate you spending some time and effort to put
this information together. I once again find myself
spending a significant amount of time both reading and leaving comments.
But so what, it was still worth it!

I am extremely impressed with your writing skills as well as with the format for your weblog.
Is this a paid theme or did you customize it yourself?

Either way stay up the excellent quality writing, it is
uncommon to see a great blog like this one these days..

Hi, I do think this is an excellent website. I stumbledupon it
;) I am going to come back once again since I bookmarked it.
Money and freedom is the best way to change, may you be rich and continue to help others.

Thanks for one's marvelous posting! I quite enjoyed reading it, you
can be a great author.I will be sure to bookmark your blog and may come back down the road.
I want to encourage you to continue your great job, have a nice holiday weekend!

Add new comment

The content of this field is kept private and will not be shown publicly.

Plain text

  • No HTML tags allowed.
  • Lines and paragraphs break automatically.
  • Web page addresses and email addresses turn into links automatically.