In previous articles about WRTNode among other things, we learned, How to add four ports LAN and a port WAN to this small router oriented development related projects with the Internet of things and the Robotics.
The first thing we must do is to connect the bi-color led, or the LEDs two different colors in the pins GPIO0 and GPIO2 just as in the following table and the rear scheme of connection; should be noted that will not need to use resistors due to the low voltages that works WRTNode.
| GPIO0 (GPIO BOARD 57)
| GPIO2 (GPIO BOARD 58)
| GND (GPIO BOARD 55)
If you use two LEDs instead of one bicolor, You must connect a bridge between the cathodes of both; On the other hand, the bi-color led they have one shared by its two anodes which reduces cabling required for this practice.
Now already we can feed our WRTNode, and connect to the Management Console of OpenWRT by means of the serial port as we learned in This previous article, to export the GPIO2, configure it as output, and assign a positive value “1“; Finally we reasignaremos a low value “0” to turn off led.
#Encendemos el led rojo root@OpenWrt:~# echo 2 > /sys/class/gpio/export root@OpenWrt:~# echo out > /sys/class/gpio/gpio2/direction root@OpenWrt:~# echo 1 > /sys/class/gpio/gpio2/value #Apagamos el led rojo root@OpenWrt:~# echo 0 > /sys/class/gpio/gpio2/value
At this point repeat the previous step, This time with the GPIO0 to test the second diode of our bi-color led and check all circuit.
#Encendemos el led verde root@OpenWrt:~# echo 0 > /sys/class/gpio/export root@OpenWrt:~# echo out > /sys/class/gpio/gpio0/direction root@OpenWrt:~# echo 1 > /sys/class/gpio/gpio0/value #Apagamos el led verde root@OpenWrt:~# echo 0 > /sys/class/gpio/gpio0/value
After checking its correct operation, We plasmaremos the the two steps above code in a script, so we will use the default text editor in this case it is VI, and We will stick the following code in our file called blinkleds; It should be noted that the shell by default in OpenWRT ES “Ash“, very similar to “bash” but with certain limitations.
#!/bin/ash #blinkleds #Exportamos los GPIO echo 0 > /sys/class/gpio/export echo 2 > /sys/class/gpio/export #Los definimos como salidas echo out > /sys/class/gpio/gpio0/direction echo out > /sys/class/gpio/gpio2/direction #Los hacemos parpadear while true; do echo 1 > /sys/class/gpio/gpio0/value sleep 1 echo 0 > /sys/class/gpio/gpio0/value sleep 1 echo 1 > /sys/class/gpio/gpio2/value sleep 1 echo 0 > /sys/class/gpio/gpio2/value sleep 1 done
You only need give Execute permissions to the script to finally run it, now the led It will Flash changing color until we interrupt the programme by pressing the key combination “CTRL + c“.
root@OpenWrt:~# chmod +x leds root@OpenWrt:~# ./leds
In this video You can see the operation of the fitting is made; If you like do not forget follow me on YouTube to not miss any of the unpublished videos I'm going to publish, regardless of the articles that I write.
In the following howto We will learn to develop a small program that will allow us to assign each led to a service, and generate visual warnings associated with events that define.
If you like you can follow me on Twitter, Facebook, Google +, LinkedIn, or share it with the buttons under this publication, If you have any questions or suggestions please do not hesitate to comment.