1. Obstacle Detection

2. Opening Activity
If you were blindfolded, what senses would you use to find things in the room?

3. Your robot can detect objects with “touch” by using its Touch Sensor
Opening Activity
You would probably use your hands to feel around to find things by touch
Your robot can detect objects with “touch” by using its Touch Sensor

4. Opening Activity
If you were a bat, you would not have to run into things, or touch them, to find them
(sound)
(sound)
A bat sends sound signals out
The signal returns to the bat, telling it the distance to the object.
The sound signals bounce off objects in the surrounding area

5. This sensor is called the Ultrasonic Sensor
Opening Activity
Your robot can also use sonar to send ultrasonic sound waves out and detect objects
This sensor is called the Ultrasonic Sensor

6. Discussion Questions
Why does the Ultrasonic Sensor have two openings in the front ?
One opening is for sending out the sound waves
One opening is for receiving the returning sound waves

7. Discussion Questions
What is the difference between the Ultrasonic Sensor and the Touch Sensor ?
The Touch Sensor must touch an object
in order to detect it
The Ultrasonic Sensor does not have to touch an object to detect it

8. Review
In previous activities we told the robot to “wait” for different conditions.
Wait for the robot to “hear” a sound
Wait for the Rotation Sensor to read 720 degrees

9. Preview
Then we will wait for the Ultrasonic Sensor to come near an object
Now we will tell the robot to wait for the Touch Sensor to be pressed

10. Preview
Don’t forget that the Ultrasonic Sensor can read both inches and centimeters, so check which one you have selected.

11. Preview
As you complete the activity, think about when you would want to use the Ultrasonic Sensor or the Touch Sensor.