Tonight I want to get an LED to flash via nodejs. After quick google search I found a package with a small guide.

After setting things up and attempting to run the quick2wire-gpio-admin it said it was already setup?

Install the package and get create the sample script

npm install pi-gpio

nano led_flash.js

var gpio = require("pi-gpio");

gpio.open(11, "output", function(err) {
    gpio.write(11, 1, function() {
        gpio.close(11);
    });
});

I was using pin 11 for my setup

run it

node led_flash.js

I ran into an error that was described in this troubleshooting guide

The Guide
gpio-admin: failed to change group ownership of /sys/devices/virtual/gpio/gpio22/direction: No such file or directory

This is a know issue and there is currently a PR on the quick2wire-gpio-admin repo that addresses it. While we are waiting for that to get pulled in we can fix it ourselves.

On your Pi navigate to:

/home/pi/gpio-admin/src
Open and modify the gpio-admin.c file:

Change this:

int size = snprintf(path, PATH_MAX, "/sys/devices/virtual/gpio/gpio%u/%s", pin, filename);

To this:

int size = snprintf(path, PATH_MAX, "/sys/class/gpio/gpio%u/%s", pin, filename);
Once you are done you will have to rebuid and install gpio-admin. Navigate to /home/pi/gpio-admin and execute the following:

make
sudo make install 

Does it now work?
If I run node led_flash.js, yes it does.

Next I wanted to make sure this is not a fluke and want to do it again with using setTimeOut() so I can offer in a delay.

var gpio = require("pi-gpio");

gpio.open(11, "output", function(err) {
        setTimeout(function(){
                gpio.write(11, 1, function(){
                        gpio.close(11);
                });
        }, 2000);
});

node led_flash.js

If I watch the LED after two seconds it illuminates and then turns off.

Success!

Mental Recap

• I read this package is old and not supported, I must do research on another way to do this interaction. (Maybe rpi-gpio)
• Typing up a node app via ssh and nano is not Ideal I need to find a better way!
• I got a LED to flash via node!
• Pin layout and what a Pin means is confusing?!