Raspberry PWM LED Control

https://electronicshobbyists.com/raspberry-pi-pwm-tutorial-control-brightness-of-led-and-servo-motor/

We'll use GPIO 24/ Pin 18 to drive the LED as in the default configuration of rc-dukes.

We are going to use the Servoblaster software see Self_Driving_RC_Car#Servo Interface - Servoblaster

cat /run/servoblaster.status 
p1pins=7,11,12,13,15,16,18,22
p5pins=

Servo mapping:
     0 on P1-7           GPIO-4
     1 on P1-11          GPIO-17
     2 on P1-12          GPIO-18
     3 on P1-13          GPIO-27
     4 on P1-15          GPIO-22
     5 on P1-16          GPIO-23
     6 on P1-18          GPIO-24
     7 on P1-22          GPIO-25

GPIO 24 has Servoblaster Id 6 so

echo 6=120 > /dev/servoblaster

will set the LED to half bright