Knowledge required
This activity assumes that students are already familiar with the ultrasonic sensor and how to use it to measure distances and display lights. It also assumes that the Otto robots for this activity have line sensors connected in digital and also analog ports.
Materials required
- Using the line sensors slides
- Otto Starter robot or only the circuit board with the line sensors
- Computers with internet and/or Bluetooth connection
Optional materials
- Using the line sensors worksheets
Learning Objectives
- Identify the key components of a robot and explain their functions.
- Recognize robotic systems in everyday life and be able to reason about how they help.
- Know that robots use algorithms to perform tasks.
- Write and upload programs that control the robot.
- Understand key concepts of programming (loops, conditionals, variables, and functions) and apply them to write effective programs for the Otto robot.
- Identify the problem to be solved and develop a plan to address it using the Otto robot components.
How do line sensors work?
Start the activity by asking students to share their ideas about how the line sensors work. They can notice that the sensors have some “small bulbs”, another good question can be “what do you think that the small bulbs in the sensors are for?”
Encourage students to share any idea they can think about!
In the second slide, it briefly specifies that Otto can use line sensors to “see” a type of light that we humans cannot.
The next slide provides a concise explanation of infrared lights. As a teacher, you have the freedom to expand upon this explanation using your own resources. Moving to the next slide, there is a short explanation about line sensors.
💡 Consider conducting a little experiment for students to “see” the infrared light through a camera as shown in this video: https://www.youtube.com/watch?v=aoPSX3wYSXo
Activity: using the sensor (digital)
Challenge students to program the line sensors in combination with the ultrasonic sensor lights so that covering the left line sensor will turn on Otto’s left “eye”, and covering the right one will turn on his right “eye”. Show them which blocks they should use (the digital blocks of line sensors) and point out that they can be used in the same way as the ultrasonic sensor to measure distance; but in this case the possible values to compare are 0 and 1.
To use the line sensors, we have four blocks in the Sensing section. Two of them allow us to read the analog value from the left and right sensors, respectively, while the other two allow us to measure the digital value. In this activity, we will be using the digital value.
Although in the Sensing section, the blocks for reading digital values are integrated within the comparison blocks (the green block), these can be used outside of them if desired. Just as the analog blocks—which come outside of the comparison blocks—can be used by connecting them to comparison blocks.
In the next slide there is a solution for the challenge. Engage students in a quick conversation about how that approach works and, if they find other possibles approaches, allow them to share their own solutions.
Possible solution to the challenge:
This program allows the robot’s eyes to react based on what the line sensors detect. In a forever loop, the robot checks the status of its two sensors: if the left sensor detects the line, the left eye lights up blue, and if it doesn’t, that eye turns off; the same happens with the right sensor and eye.
In this way, each eye immediately reflects what the sensor on its side perceives, making it easier for students to visually and directly observe when the robot is detecting the line on the ground.
Digital vs Analog
The next two slides provide a simple explanation about what digital and analog mean in the context of sensors.
Activity: using the sensor (analog)
The last slide shows how to use the serial monitor and the analog line sensor blocks to display the analog values read by the sensors in real time. To make it easier to read, we added a 1 second wait between each reading of the sensors, feel free to add extra time or removing it.
Activity expansion
The next slide shows how to use the serial monitor and the analog line sensor blocks to display the analog values read by the sensors in real time. To make it easier to read, we added a 1 second wait between each reading of the sensors, feel free to add extra time or removing it.
Program to read analog values from line sensors:
12-2_measure-line-sensors.otto
When you run this program and open the serial monitor, you will see the written texts + sensor values appear:
We can see how the values change if, for example, we pick Otto up or move him to a different colored surface.
Removing the wait of 1 second will cause the values on the serial monitor to appear very quickly, making it impossible to read and interpret the data. You can demonstrate this to your students to explain the importance of adding this time delay and also to demonstrate the speed at which the machines operate.
Activity expansion
This last activity could be expanded by adding extra challenges, like:
- As well as with the digital blocks, use the analog blocks to measure values and trigger some actions such as playing sounds or displaying lights. Due to the high quantity of possible values, students can get creative by including a large range of possible actions depending on the value measured.
- Ask your students to share their ideas about “What’s better: digital or analog?”
Lesson Evaluation
- Students participated in discussions about infrared light and its relevance to line sensors.
- Students successfully coded the line sensors using digital blocks to detect light and dark surfaces, integrating this with the lights of the ultrasonic sensor.
- Students understood the differences between Digital and Analog in the context of line sensors.
- Students demonstrated their ability to use the serial monitor and analog line sensor blocks to read and display analog values in real-time.
- Students applied their knowledge effectively to control Otto using both digital and analog outputs from line sensors, demonstrating comprehension of sensor functionality in robotics.
- Lesson objectives were achieved as students successfully used line sensors to detect light and dark surfaces, distinguishing between digital and analog sensor outputs.
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The duration of this lesson is approximately one hour. You can find the definition of learning objectives at the bottom of this guide to align with your curriculum requirements.
Materials required
- Lesson slides
- Lesson worksheets
- TV, projector, or big screen to display the class videos
- Big paper or cardboard (white)
- Tape (black)
- Scissors
Computers, tablets or smartphones are optional, they can be used as digital tools for students to do further research and take additional notes.
Connect
The class begins by displaying the first slide and asking the students “What do you see here?’“
[Pause and wait for students to provide answers, which may include mentions of a robot arm and two wheeled robots moving boxes].
The teacher will then guide the class in a conversation about the nature of robots, exploring questions such as: ‘What is a robot?’ ‘When does something turn into a robot and when is it just a machine?’
Moving on to the second slide, the teacher will introduce the topic of the usefulness of robots to humans. Students should share their ideas about how robots can be useful.
[This conversation is expected to last approximately 4-5 minutes]
Afterwards, on the third slide, the students will watch a video that explains the concept of what a robot is. Following the video, they will have the opportunity to share their personal experiences with robots. The teacher can guide the conversation by asking specific questions, such as: ‘Have you ever played with a robot or built one?’ ‘Do you have any robotic devices at home, like a vacuum cleaner, that you consider to be a robot?’
[The video has a duration of 4 minutes, and the discussion about personal experiences is expected to take an additional 3-5 minutes]
On the next slide, the teacher will organize small groups consisting of 2-3 students. Each group will be assigned a specific robot to investigate. The students can conduct their investigation by using the internet or through provided materials, either digital or physical. Some popular real-life robots for the students to explore are:
As a teacher, feel free to research other robots to add to the list. By the time you teach this lesson, there could be some new and popular robots.
During this activity, students will gather information about their assigned robot and gain knowledge about how robots are being utilized in daily life. At the end of the investigation, each group will give a brief presentation about the robot they investigated.
Here the students will use the first worksheet
[This activity is expected to take approximately 10-15 minutes in total, allowing sufficient time for research and presentations]
Make
On the fifth slide, the teacher will introduce the HP Otto robot by showing a video about its features and capabilities. After watching the video, the teacher will demonstrate a built robot to the students, showcasing its physical components and explaining how they contribute to its functionality.
[To further engage the students, the teacher can connect the robot to the Otto web control app, demonstrating how to operate and control the robot using the app’s interface.]
On the next slide, a diagram displaying the internal connections of the robot will be shown. Using the web control app, the teacher will demonstrate how each component of the robot works.
To engage the students, the teacher can actively involve them in the activity. For example:
- Buzzer: The teacher can play various sounds available on the app and ask students to suggest or choose which sound they would like to hear.
- LED ring: The teacher can ask students (up to a maximum of 12) about their favorite colors and display them on the LED ring.
- Ultrasonic sensor: The teacher can activate the avoidance function and make the robot move around the classroom. Students can participate by intercepting the robot’s path with their hands, observing how the robot changes its direction in response.
- Line sensors: Although the line tracking activity will be conducted later, the teacher can explain how the infrared sensors work at this stage.
In the next activity, the entire group will work together to define a racing track circuit for the robot to navigate. The teacher will guide the students in this process, but it is important to allow the students to make the decisions in order to foster their creativity and engagement. The goal is to define a circuit that includes specific landmarks or areas within the classroom for the robot to move around.
For example, the students may decide to start the circuit in front of the teacher’s desk, then describe a square around James’ seat, move in a zigzag pattern between Eva and Raidy’s seats, and finally return to the teacher’s desk. [To maintain efficiency, the teacher should encourage the students to make quick decisions, aiming to complete the circuit definition within 1-2 minutes]
[Optional]: As an additional challenge, the teacher can allow students to take turns controlling the robot and measure their individual completion times. This can add an element of friendly competition among the students.
The next activity is similar to the previous one, but this time the students will create a line track using ‘tape’ on a large white piece of paper or cardboard.
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