2. Project Overview Introduction Frame Build Motion Power Control Sensors
Advanced Sensors
Open design challenges
Project evaluation

3. LESSON 07

4. LESSON 07 STARTER
Describe to your partner how a sensor would help a robot operate, including what information it would take in, and how the robot response would work … In the dark? … underwater? … without a map? … in hazardous circumstances? … to avoid putting too much pressure on a surface?

5. DEVELOPING SENSOR USE
Building programmes and setting scenarios Having learnt about how robots are built and designed, it is now time to focus on programming them. Your tasks for the coming lessons will be to write programmes to upload to the Tumbler, fit sensors to them accurately, and then test and prove a robot behaviour (i.e. you can programme the Tumbler to act or react in a certain way).
Bump Sensor
Limit Switch
Line Follower
In this scenario the Tumbler needs to simply stop when it hits an object. The bump sensors are tough and robust on impact, therefore suitable for this behaviour. A large block of wood will suffice as a blockade.
In this scenario the Tumbler will slow down when it drives over something. The limit switches are or sensitive, and when mounted underneath the robot will trigger when they brush over the sheet of wood on the surface.
In this scenario the Tumbler will follow the black line as it curves around an object. For this to work, a pair of line follower sensors are used, which will track light/tone change of the surface either side of the line which is insulation tape.
Level of challenge: EASY
Level of challenge: Medium
Level of challenge: HARD

6. DEVELOPING SENSOR USE
Programmes in easyC easyC V4 is a programming software package that allows you to control the finest of features, inputs and outputs, of the cortex. Here are the three programmes written for the Tumblers and their behaviours.
Bump Sensor
Limit Switch
Line Follower
Level of challenge: EASY
Level of challenge: MEDIUM
Level of challenge: HARD

7. DEVELOPING SENSOR USE
Programming the line follower (hard) In each scenario here, the video shows the behaviour programmed using the approach shown previously.
Bump Sensor
Limit Switch
Line Follower
Bump Sensor video
Limit Switch video
Line follower video
Level of challenge: EASY
Level of challenge: EASY
Level of challenge: HARD

8. Programme writing for the line follower video
DEVELOPING SENSOR USE
Programming the line follower (HARD) Watch the following tutorial which takes you through the process of writing a programme for the robot fitted with the line follower sensors.
Programme writing for the line follower video

9. DEVELOPING SENSOR USE
Learning objective: Learn how to apply sensors to different scenarios and how sensors can add accurate control Apply sensors to a range of simple challenges.
Build and program a robot with bumper switches to hit a sequence of targets in the fastest time …
Scenario:
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 VEX Tumbler.
Design a program that navigates the robot around the chamber hitting each target in turn in the fastest time. You will need to upload the file to your Tumbler, fit the bumper switches, and prove its outcome.
Extension task:
Adapt the field by adding pads that the Tumbler must avoid, and consider a Tumbler design and easyC program that will work around these pads.

10. Bump challenge outcome
DEVELOPING SENSOR USE
Solution
Video
Watch the video below to see a working outcome. Here is a screen shot of part of the program that will achieve it. Copy this onto the program sheet.
Bump challenge outcome

11. LESSON 07 PLENARY
As a class, let us consider the following questions? A. What elements of your program worked? B. How successful was your design strategy? C. How could you have achieved the outcome better in your program? D. How could you have achieved the outcome better in the Tumbler build?

12. SUMMARY Today you have:
Learning objective: Learn how to apply sensors to different scenarios and how sensors can add accurate control Apply sensors to a range of simple challenges..
Today you have:
Applied sensors in new and challenging contexts.
Problem solved to achieve a control outcome using sensors.
Explored and developed your knowledge of sensors for robotic applications.