Sensors

These are what robots need to know the world around them.

Add a sensor to your robot to bring it to life!

Session 3 Aims:
  • To know what a sensor is
  • Be able to use the EV3 Model to detect lines using a sensor
  • Be able to use a sensor to control action
  • Understand how speed can affect sensing on an EV3 Model

Suggested time for session is 110 minutes (This can be broken into two sessions if needed) and it could be a lot longer!
Time / Activity / Resources needed
5 mins / Introduction and aims of session (Slides 1 and 2)
Discussion - What is a sensor?
How many sensors can students name? Discuss in relation to Slide 3. / “Lesson 3 PPT”
20 mins / Focus – draw students’ attention to the help facility in the EV3 Software (Slide 4)
Discussion – The Colour (and Light) sensor(Slide 5)
Outline explanation of how it works.
Demonstrate how the sensor can be used to detect reflected light.
You can see the readings of the sensor by clicking on the Port View in the bottom right corner of the EV3 software. (NB: Values will only show if you are connected via Bluetooth/WIFI or a physical cable).
The block you will use is the Wait Block (Slides 6 – 7)
Students practise getting their EV3 Model to STOP at a black line. They need to understand that it is the measurement that the sensor takes that informs the subsequent action – LOGIC OPERATOR.
To support them in this use Robot Educator Activity – Stop at a line / “Lesson 3 PPT”
Colour Sensor
EV3 Software
Robot Educator Activity – Stop at a line
20 mins / Challenge 1 – Parking (stopping at a line)
-Introduce the real world problem. Show the ‘interesting!’ video (Slide 8)
-Students must parallel park the EV3 using the Large motors and Colour/Light sensor. The sensor is simply used to find the stopping line from which they should then reverse and turn from. (Slide 9)
NB: The Training Mat doesn’t have a clear run to the line so students may have to adjust their program so the EV3 Model doesn’t stop at the printed ruler.
Extension – they could always introduce a reverse parking sound into their programs – lots of great noise! It will also introduce them to the idea of multitasking. There is a great example of this in Robot Educator Activity – multitasking, which they can then apply to their program. / “Lesson 3 PPT”
Training mat 1
2 plastic cups
EV3 software
EV3 Model
Robot Educator Activity – multitasking
20 mins / Challenge 2 – Following a line(Slide 10)
Students to use the Switch block to program the EV3 Model to follow the black circle on Training Mat 2.
Robot Educator Activity – Switch is a great way to support students in this challenge. / “Lesson 3 PPT”
Training mat 2
EV3 software
EV3 Model
Robot Educator Activity – Switch
20 mins / Challenge 3 – Knockout Challenge (Speed vs. Control)(Slide 11)
Students to work out the optimum speed they can go while using a sensor.
-10 minutes to program/calculate
- 10 minutes (it can take much longer!) to run the competition – you may want to mark out your own track (black insulating tape) and run multiple robots – winner is the first robot to get back to its starting point!
Students must learn that full power isn’t necessarily the fastest when using a sensor, as the sensor needs time to pick up a reading. / “Lesson 3 PPT”
Training mat 2
EV3 Core set
Black insulating tape (optional)
20 mins / Challenge 4 – Detect and React(Slide 12)
Using the Colour sensor, students must program the EV3 Model to detect and read out the matching colour. Use Training Mat 3 as shown on the demo video. / “Lesson 3 PPT”
EV3 software
EV3 Model
Training Mat 3
Extension(Slide 13)
Demonstrate the Colour Sorter. You could build the model or simply show the video in the EV3 Software – Model Core Set – Model Instructions – Colour Sorter. / “Lesson 3 PPT”
Model Core Set – Model Instructions – Colour Sorter (video).
5 mins / Plenary(Slide 14)
Draw out key learning points about using sensors to control actions.
Video of engineers solving the real world problem of parking by using a range of sensors and technology. / “Lesson 3 PPT”