Simple WEB GPIO
From emboxit
File:RPI-SIMPLE-WEB-GPIO.jpg
Diagram based on DIVERTEKA-2), shows the setup for simple Raspberry-Pi WEB-controlled GPIO.
Contents
Why
- based on tutorial DIVERTEKA-2)
- This setup is very simple
- No Security, no passwords
- Only 3 simple files needed
- The files are small and easy to understand
- helps to understand:
- GPIO virtual files creation
- GPIO virtual files permissions
- rc.local
- Simple script file (gpio.sh)
- The minimal php program needed
- Is easy to expand for more GPIO lines
Setup of Raspberry-Pi WEB-controlled GPIO
- Copy gpio.sh to directory /etc/rc.local
- This can be done with ftp client but not directly as ther is no permission to access /etc/rc.local
- First brink gpio.sh to /home/pi with FTP
- Then from/home/pi
sudo su cp ./gpio.sh /etc/
Now gpio.sh is in /etc directory
- Copy xue1.php to /var/www
cp ./xue1.php /var/www/
- Edit rc.local
sudo nano /etc/rc.local
at the end of the file should be like this
fi # Pin GPIO14 (OUT) echo “14″ > /sys/class/gpio/export chmod 777 -R /sys/class/gpio/gpio14 echo “out” > /sys/class/gpio/gpio14/direction # Pin GPIO8 (IN) echo “8″ > /sys/class/gpio/export chmod 777 -R /sys/class/gpio/gpio8 echo “in” > /sys/class/gpio/gpio8/direction exit 0
The call to gpio.sh from rc.local did not work, but having the script inside the rc.local, as above, works!
Source code
xue1.php
<php> <?php
$lectura=exec("cat /sys/class/gpio/gpio8/value");
if (isset($_POST['button1']))
{
exec("echo \"1\" > /sys/class/gpio/gpio14/value");
}
if (isset($_POST['button2']))
{
exec("echo \"0\" > /sys/class/gpio/gpio14/value");
}
if (isset($_POST['button3']))
{
$lectura=exec("cat /sys/class/gpio/gpio8/value");
}
?>
<html> <head>
<title> ** GPIO Control ** </title>
</head>
<body bgcolor="#c0c0c0">
== GPIO Control - XUE001 Board ==
<form method="post">
DIGITAL (OUTPUT) => <button name="button1">ON </button> <button name="button2">OFF</button>
</form>
<form method="post">
DIGITAL (INPUT) <button name="button3"> READ </button> <input type="text" name="valor" value= "<?php echo $lectura; ?>" >
</form>
</body>
</html>
</php>
gpio.sh
#!/bin/sh # # # GPIO-Pin 14 (OUT) echo "14" > /sys/class/gpio/export chmod 777 -R /sys/class/gpio/gpio14 echo "out" > /sys/class/gpio/gpio14/direction # GPIO-Pin 8 (IN) echo "8" > /sys/class/gpio/export chmod 777 -R /sys/class/gpio/gpio8 echo "in" > /sys/class/gpio/gpio8/direction
rc.local
#!/bin/sh -e # # rc.local # # This script is executed at the end of each multiuser runlevel. # Make sure that the script will "exit 0" on success or any other # value on error. # # In order to enable or disable this script just change the execution # bits. # # By default this script does nothing. # Print the IP address _IP=$(hostname -I) || true if [ "$_IP" ]; then printf "My IP address is %s\n" "$_IP" fi # GPIO export script # /etc/gpio.sh # GPIO-Pin 14 (OUT) echo "14" > /sys/class/gpio/export chmod 777 -R /sys/class/gpio/gpio14 echo "out" > /sys/class/gpio/gpio14/direction # GPIO-Pin 8 (IN) echo "8" > /sys/class/gpio/export chmod 777 -R /sys/class/gpio/gpio8 echo "in" > /sys/class/gpio/gpio8/direction exit 0
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