Application note - fitlet2 controlling front LEDs

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  • This document provides an example to control the fitlet2's front LEDs.
  • fitlet2 has 2 LEDs, LED1 and LED2. Each of them has GREEN and YELLOW parts that can be controlled separately.
  • This document is applicable to fitlet2 running Linux or Windows.


  • Download the driver from - Link

The package contains:

  • Driver\fitlet2.LED.Driver.exe - Driver installer.
  • Sample Applications\SetLed\ - Sample application demonstrates the LED control (VS project)

There are 2 options for LED control:

1. Use the pre-made applications for LED control:

   Led1Green.exe: Turn on the LED1 green
   Led1Yellow.exe: Turn on the LED1 yellow
   Led1Off.exe: Turn off the LED1
   Led2Green.exe: Turn on the LED2 green
   Led2Green.exe: Turn on the LED2 yellow
   Led1Yellow.exe: Turn off the LED2
   After the driver installation, all these applications can be found in the C:\Program Files (x86)\LED\ folder.

2. Develop an application using the DLL and LIB files.

After the driver installation, the LED.dll, LED.lib and LED.h files be found in the C:\Program Files (x86)\LED\ folder.


In Linux kernel there are 4 related GPIOs: GPIO435, GPIO436, GPIO437, GPIO438.

  • GPIO435 - LED1 GREEN
  • GPIO437 - LED2 GREEN

To control the GPIOs need to login as root (root password required):

$ su

To control for example LED1 GREEN part:

$ echo 435 > /sys/class/gpio/export
$ echo out > /sys/class/gpio/gpio435/direction
$ echo 1 > /sys/class/gpio/gpio435/value
# LED1 should be GREEN now
$ echo 0 > /sys/class/gpio/gpio435/value
# LED1 should be OFF now
$ echo 435 > /sys/class/gpio/unexport

The GPIO framework and GPIO sysfs interface are documented in