Raspberry Pi - My first GPIO LED

Following the directions on these pages:

[1] http://elinux.org/RPi_Tutorial_EGHS:LED_output (Circuit 1 - Basic LED Driving Circuit)
[2] http://elinux.org/RPi_Low-level_peripherals#GPIO_Driving_Example_.28Shell_script.29

See this Simple Guide to the RPi GPIO Header and Pins page for how the Pi's Pin numbers map to the GPIO Pins. The guide's Pin diagram is shown below:

I will use Pin-11 on the Pi, which translates to GPIO-17. Therefore, I use GPIO-17 in the shell.

pi@raspberrypi ~ $ sudo -i
root@raspberrypi:~# echo "17" > /sys/class/gpio/export
root@raspberrypi:~# echo "out" > /sys/class/gpio/gpio17/direction
root@raspberrypi:~# echo "1" > /sys/class/gpio/gpio17/value
root@raspberrypi:~# echo "0" > /sys/class/gpio/gpio17/value

The following picture shows the setup.

The top Red-Rail is Pin-11 (GPIO-17) output. The bottom Red-Rail is Pin-2 (+5V). Both Blue-Rails are Pin-6 (GND).

There's an LED connected between Pin-2 (+5V) and Pin-6 (GND), in series with a 10k-Ohm resistor. This will always be On, and just proves that the Pi is supplying power.

There's an LED connected between Pin-11 (GPIO-17) and Pin-6 (GND), in series with a 10k-Ohm resistor.

The shell commands as specified above, will turn the LED On and Off.

In practice, the LED connected to 5V is brighter than the LED connected to GPIO-17. I assume this is because GPIO voltage levels are 3.3 V.

The GPIO-connected LED wasn't very bright. I think this is a combination of the lower voltage level (3.3V) and using a resistor value 37 times bigger than the 270-Ohm resistor recommended in [1].

To increase the brightness of the GPIO LED, I used 3x10k-Ohm resistors in parallel to decrease resistance to 3.3k-Ohm.