lesson-4.md

@@ -112,12 +112,14 @@ A final observation relating to this application is that the robot stopped immed
 It is possible to make a line follower with just one light sensor that follows the line more smoothly and drive faster if a PID regulator is used \[2\]. Try this.
 
 #### Execution ####
-In this exercise, we follow the description of a PID implementation given in the exercise sources<<<<<ref>>>>>.
+In this exercise, we follow the description of a PID implementation given in the exercise sources<<<<<ref>>>>>. We refer to this article for the theoretical reasoning for building a PID algorithm.
 
-##### Big Bang interpretation #####
+##### Big bang interpretation #####
 First, we tried to integrate the entire PID pseudo code solution into our application in one step. As one would expect, this caused the robot to only react slightly to the black line, but mostly spin around in circles. See (the video)<<<ref>>>> for a video of the behaviour.
 ![Spinning](/uploads/2a1008bd4c054047bb04d8ec8f85b9d4/Spinning.m4v)
 
+Given the nature of big bang integration, the cause of this behaviour can be numerous factors. Most likely would be the amount of power given to the robots motors and variables directly translated from the source application.
+
 ### Color Sensor ###
 
 #### Description ####