Obstacles Assignment #5

1. What did the robot do?
    - It moved around the table and when it bumped objects it would backup a little bit and then turn and keep going.

2. What caused the robot to stop?
    - it was programmed to stop when it touched something.

3. Do you think it’s a good idea for the robot to run into obstacles and stop?
    - No, because the object could fall on the robot. The robot should move out of the way.

4. What are the  benefits and drawbacks of this behavior?
    - The benefit of using a touch sensor is that you will definitely know where the object is, but a drawback is that you could end up knocking the objet over or moving it.

5. What did the robot do?
    - The robot moved around the table and stayed about 50 cm away from the walls and the objects.

6. What caused the robot to stop?
    - The robot would stop when it got too close to an object.

7. How far away from the obstacle did the robot stop?
    - 50 cm.

8. What are the benefits and drawbacks of this behavior?
    - The benefit of using an ultrasonic sensor is you don't have to touch the object, but a drawback is that you don't know for sure if that's how far away the object is.

9. How reliable is this sensor as opposed to the touch sensor?
    - It's not. The ultrasonic sensor could be a bit off and then you think something is far off when really it's rapidly approaching and then it hits your robot and kills it!
    Well, the ultrasonic sensor could be better than the touch sensor because you don't affect the object, it doesn't touch, it just senses it. Like a ninja.

10. Think about the Construct Phase that you just completed and compare using the touch and ultrasonic sensors.
    a. What is the main difference between the two programs?
        - The touch sensor has to be right by an object while the ultrasonic sensor can be programmed to be any amount of distance away.
So I guess the difference is the distance the objects can be from the robot before the robot senses it.

    b. What is the main difference in the robot’s behavior when you use each of the different sensors?
        - The main difference is the time it took the robot to figure out it couldn't go in a certain direction. Using the touch sensor the robot would go until it hit the wall, but when using the ultrasonic sensor the robot was able to see that the wall was close and it changed its course.
11. The ultrasonic sensor allows you to stop before you reach an object, rather than after you’ve run into it. What are the benefits and drawbacks of this behavior?

12. The touch sensor only has two settings, pressed and not pressed. The ultrasonic sensor, on the other hand, can sense any distance between 0 and 200 centimeters. 
    a. Why do you need to set a threshold level for the ultrasonic sensor, but not for the touch sensor?
    - Because for the ultrasonic sensor there are different distances, but with the touch sensor there is only pressed and not pressed.

    b. What happens to the robot’s behavior as you change that threshold level for the ultrasonic sensor?
        - If i make the threshold higher, it stays farther away from objects. And when I lower the threshold the robot gets closer to objects before it stops.

13.
    a. List three reasons why you would want to use a touch sensor on a real world robot to detect obstacles.
        1.) A touch sensor would be more preferable to some people because it's easier to hit something and make sure that it worked instead of waving your hand in front of an ultrasonic sensor.
        2.) It would be more battery efficient than an ultrasonic sensor because it wouldn't sense when something went by it. It would have to be touched, and that would save battery life.
        3.) There could be different reactions depending on if the sensor was pressed or bumped or released.

    b. What kind of robots could use touch sensors in this way? Describe at least two.
          - a robot kitten. I had one when I was little.
          - a sink. The water dispenser on the kitchen sink. You could just touch it instead of having to lift or twist the knobs.

    c. Describe at least one situation where a touch sensor could NOT be acceptably used as an obstacle detector.
          - A touch sensor wouldn't work in an race because it would take too long to bump in to something and then get back on track. It would be easier to sense something with the ultrasonic sensor.

14.
    a. List three reasons why you would want to use an ultrasonic sensor on a real world robot to detect obstacles.
        1.) The robot wouldn't have to touch anything with the ultrasonic sensor.
        2.) The robot could actually tell you how far away something is.
        3.) A blind person could use an ultrasonic sensor and have a better understanding of their surroundings.

    b. Does the ultrasonic sensor provide reliable detection for every type of possible obstacle.
          - No. If the obstacle is slanted toward your robot, and the ultrasonic sensor picks up the bottom, the farthest part, you could end up bumping your robots head.

    c. Describe at least one situation where an ultrasonic rangefinder could be acceptably used as an obstacle detector.
          - If you are trying to find something but you can't physically see it. Like if you are in a boat trying to find a man eating shark beneath you in the dark abyss.

    d. Describe at least one situation where an ultrasonic rangefinder cannot be acceptably used as an obstacle detector.
          - If you are looking for something too small to be detected.

15. What other kinds of sensors could be used to detect obstacles, and how would you use them?
          - Another sensor is a sound sensor. It detects sounds and can be programmed to speed up or slow down depending on the noise level.

16. What does the sensor show when it has difficulty detecting anything?
          - ???

17. Does the shape or curvature of an object make a difference?
    -Yes, depending on what area gets touched, it could be more of a distance or less of a distance away from the actual bulk of the object.

18. Does the sensor detect soft or hard objects better? Why do you think this is?
          - I think the touch sensor detects hard objects better, because there's less time to squish, I guess.

19. What is the smallest object detected?
          - In class? A pencil.

20. Does the sensor detect thin objects well?
          - No, it won't detect it accurately if it's moving.

21. Turn the sensor 90 degrees on its side so it is positioned “upright.” Does it detect?
          - Not as well as when it's the way it's supposed to be.