If you are familiar with linux, you may know that everything in linux is a file. You can talk to a hardware as if you are writing to a file. There are 4 on board LEDs in BBB. You can play with that LED. Go to /sys/class/leds/beaglebone:green:usr3/ cd /sys/class/leds/beaglebone:green:usr3/ If you write a '1' to the file corresponding to LED3, then it will light that LED. Writing '0' will switch off the LED. echo 1 > brightness It will switch on the LED forever. :-) If you want to switch off it again type echo 0 > brightness Let's do it in c. First ssh into your BBB (refer here ). Then create a directory to work with. mkdir helloworld cd helloworld Open your favourite texteditor. nano LEDBlink.c Then type this program. #include<stdio.h> int main() { FILE *LEDHandler=NULL; char *LEDPath="/sys/class/leds/beaglebone:green:usr3/brightness"; if(LEDHandler=fopen(LEDPath,"r+")){