2. Using the Bumper switch
LESSON 04
Using the Bumper switch

3. The Bumper switch
The purpose of this lesson is to introduce students to the Bumper Switch and how they are used to control the robot.

4. Programming using a Bumper switch
Learning objective: Students will know how Bumper Switch sensors can be used to control a robots movement
When the Bumper Switch sensor is pressed, it closes an electrical circuit, allowing current to flow.
If the Bumper Switch is released, the circuit is broken and no current flows. The flow (or lack) of current is detected by the VEX IQ, allowing it to determine the Bumper Switch is pressed

5. Fitting a Front Bumper switch
Learning objective: Students will understand how to attach the Bumper Switch sensors to the Basebot
Task 1: The Build – Fitting the Bump Sensor
Fit the Bumper switch as shown on the picture opposite
This can be done using four of the 1x1 connector pins.
Once in position on the robot, connect the Bumper Switch to the Brain using a Smart Cable of appropriate length.
Connect the Bumper Switch into Port 8 of the Brain

6. Matching Exercise Task 2: Boolean Logic
Learning objective: Students will know how Bumper Switch sensors can be used to control a robots movement
Task 2: Boolean Logic
Fill in the missing gaps on your worksheet by using picking words from the word bank at the bottom of the page that match the ROBOTC symbols.

7. Programming using a Bumper switch
Learning objective: Students will know how Bumper Switch sensors can be used to control a robots movement

8. Bumper switch test Task 1: Using the ‘waitUntil’ Command to Stop
Learning objective: Students will be able to program the Basebot using the Bumper Switch sensor and ‘waitUntil’ command
Task 1: Using the ‘waitUntil’ Command to Stop
In this scenario the Basebot needs to simply stop when it hits an object. The Bumper Switch is tough and robust on impact, therefore suitable for this behaviour. A large block of wood or the field perimeter will suffice as a blockade.
Task 2: ‘waitUntil’ Command to Change Direction
In this scenario the Basebot needs to simply change direction when it hits an object.
Using your knowledge of these commands, you must now attempt the challenge and complete it using these different codes.

9. Secret Chamber Challenge
The Challenge: You have found a Secret Chamber at the entrance to a suspected hidden gold store, you can see a number of points in the chamber that need to be pressed in a certain order as quickly as possible to open the chamber door, but the gap can only fit in a small robot – the Basebot – to activate them autonomously.
Design a program that navigates the robot around the chamber hitting each target in turn in the fastest time. You will need to download the file to your Basebot and prove its outcome.

10. Secret Chamber Challenge

11. Secret Chamber Challenge
Sample Solution

12. LESSON - PLENARY As a class, let us consider the following questions?
A. What type of sensor is the Bumper Switch?
B. What type of devices might use a Bumper Switch?
C. Are there any problems that might happen using a single Bumper Switch? D. What improvements could you make to the robot to overcome any problems discussed in the answer to the last question?

13. Summary Today you have: Learned how the Bumper Switch works.
Learning objective: Students will know how Bumper Switch sensors can be used to control a robots movement. Students will understand how to attach the Bumper Switch to the Basebot and then program the Basebot using the ‘waitUntil’ function. Students will be able to design a program for the Basebot to take part in the Secret Chamber Challenge.
Today you have:
Learned how the Bumper Switch works.
Fitted the Bumper Switch to the robot.
Programmed the Basebot using the ‘waitUntil’ and command
Attempted to enter the Secret Chamber by completing the Challenge