(I will answer your questions to my best ability. I'm quite new to programming and only know the basics. I have been getting ideas from the samples I see around the net and use them to add them to my projects.)
1.Used to manipulate the frequency (in micro seconds) as which I would like to see measurements.
2. Makes it so that the HC-SR04 sends the pulse and measure the amount of time taken to return to get the distance.
3. Tells the servo to rotate with a certain speed in one direction. 1500 being no movement. One is 1400 and the other is 1600 because the servos are opposite in the way they have been positioned.
4. Approximately 2cm-500cm
5. Effectual angle is <15°
I am extremely appreciative of the time you are taking to view my project. You really don't know how much this means to me. Thought you should know.