Optical sensors for navigation
Lesson details
Learning outcome
I can describe and use optical reflective sensors to react to an environment.
Key learning points
- Reflective optical sensors detect surface contrast.
- Reflective optical sensors emit infrared light and measure how much is reflected back.
- Light coloured surfaces like white reflect more infrared, while dark surfaces like black lines reflect less.
Keywords
Environment - the surroundings or conditions something exists in or reacts to
Optical - something that relates to light and vision
Reflective - something that bounces back light or other waves like sound
Common misconception
The sensor follows the line like a smart camera.
The sensor sends data back to the microcontroller to say whether light or dark is detected. The written code uses this data to decide how the buggy should respond.
Teacher tip
Engage learners by sharing products that use optical sensors such as a line following robot or a TV remote and IR receiver to physically demonstrate how optical reflective sensors work. Let students interact with the sensor and discuss their ideas for other useful applications of optical sensors.
Equipment
Raspberry Pi Pico, two optical sensors, jumper wires, previous project materials such as a buggy chassis, Thonny software.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What does a sensor do?
Q2.What does an ultrasonic sensor measure?
Q3.What does an ultrasonic sensor use to measure distance?
Q4.Which formula is used by ultrasonic sensors to calculate distance?
Q5.Put these steps in order for how an ultrasonic sensor measures distance:
Q6.What device receives data from sensors and makes decisions based on that data?
Assessment exit quiz
6 Questions
Q1.What does a reflective optical sensor detect?
Q2.What type of light do reflective optical sensors use?
Q3.Match each keyword to its meaning:
related to light and vision
bounces back light
the surroundings or conditions
receives sensor data and makes decisions
Q4.What happens when a reflective optical sensor passes over a white surface?
Q5.What is the main job of the microcontroller in a line-following robot?
Q6.Put these steps in order for how a reflective optical sensor works:
To help you plan your 11 computing lesson on: Optical sensors for navigation, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 11 computing lesson on: Optical sensors for navigation, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 computing lessons from the Using physical computing to create a robot buggy unit, dive into the full secondary computing curriculum, or learn more about lesson planning.