Lesson5.md

@@ -20,19 +20,28 @@ We will experiment with using a PID controller for getting the robot to stand up
 
 We plan (or hope) to finish the activities within 5 hours.
 
-For these exercises Camilla will be taking notes, Nicolai will be programming and Emil and Ida will be in charge of the experiments.
+For these exercises Ida will be taking notes, Nicolai will be programming and Emil and Camilla will be in charge of the experiments.
 
 ## Results
 ### Self balancing robot with light sensor 
 ---
-We started out by rebuilding the robot with respect to the building instructions in [2]. 
+We started out by rebuilding the robot with respect to the building instructions in [1]. After this rebuild the robot now only had two wheels as seen in Figure 1. 
 
-We started by running Bagnall's program [2] without modifications, in the large working space in the Zuse building. This didn't give a good result: The robot just rushed ahead, either upright or sliding around on its "back", never holding its balance and standing still. The only reason that the robot was sometimes able to keep upright was that when tilting forwards, it landed on its light sensor which then held up the robot like a crutch (as seen in Video 1).
+![rebuild two wheel robot] (TODO) 
+*Figure 1: Robots new look after rebuild
+
+We started by running Bagnall's program [2] without modifications, on the floor in the large working space in the Zuse building. This didn't give a good result: The robot just rushed backwards, either 'standing upright' leaning on the sensor placed at the front, or sliding on it's back, and therefore never holding its balance
+(as seen in Video 1).
 
 [![Robot performing poorly using Bagnall's program](SOMEURL.jpg)](video IMG_2238.MOV)
 
 *Video 1: Robot racing around and resting on its light sensor.* 
 
+Going backward on its back is expected behavior, as the sensor in this situation measures a hgih raw value of reflected light and therefore assumes that the sensor is far away from the ground and tries to flip itself up by setting full speed backwards on its motors. This doesn't work as the robot doesn't have enouyght power.  
+
+Going backwards on its front is however not expected behavior, as the robot should in fact try to catch its weight by driving forward as it does until the sensor hits the ground. When leaning on the floor the sensor must therefore see a high raw value which means that it doesn't see any reflected light and thinks that it is in fact leaning backwards instead of forward and thereby trying to go backwards. 
+
+
 With the goal of obtaining a better understanding of the significance of the physical environment, we then tried to take Hurbain's reccomendations for environmental conditions [1] into account. According to Hurbain, the NXTway requires the following conditions to be satisfied:
 
 1. The lighting must not interfere with light sensor. Hurbain suggests trying out the robot in a dark room or a room lit only by fluorescent light.