Robotics 1.0 Lesson Plan
Lesson 17: Sun Seeker

Purpose: Automate a plant pot to rotate toward better light using a servo motor and a pan tilt mechanism.

No. of. Classes

1 - (Time : 1:30 minutes, each group maximum 4 children).

Materials Required

Laptop or desktop with Mu Editor installed.

CircuitPython installed on CPX board.

Circuit express board (CPX), Crickit, USB cable and 5v battery.

Photoresistor sensor.

Servo.

Jumper wires.

Pan tilt kit for mounting the pot.

Curriculum Content 6.10 Photoresistor (external).
7.1 Servo Motors
7.5.2 Motion Types - Rotational
Prior knowledge

Understanding of photoresistors (light sensors), servo motors and how they move to different angles, basic CircuitPython control of servos, and safe use of external power with Crickit.

Exercises

Exercise:1


  • Assemble a pan tilt with a servo using this video and use a tape to mount the pot on top of it


  • Click here to view the connection diagram for the servo motor and light sensors. You will need to attach two light sensors to two sides of the pot for this exercise

  • Implement the pseudocode in this document. Recall the code for servo motors from previous lessons.


    • Solution


  • Click here to see the solution video for Exercise 1.
  • Click here to see the solution document for the code for Exercise 1.
  • Click here to view the code explanation for Exercise 1.
    • Teacher's Instruction
    1. Explain the goal of the activity, which is to rotate the plant pot toward the brighter light.
    2. Show how two photoresistor sensors are placed on the left and right sides to compare light levels.
    3. Demonstrate how the pan tilt mechanism holds the pot and how the servo moves it left or right.
    4. Explain how the program reads light values from both sensors and decides which direction the pot should turn.
    5. Ask students to shine a torch or move their hand over one sensor and observe how the pot reacts.
    6. Discuss why checking sensor values continuously is important for smooth and responsive movement.
    7. Ask students to unplug the power and carefully remove the wires after the activity.
    8. Teachers can show this animation so students can visualize how systems follow light. View Solar Energy Animation
    9. Are two light sensors enough to accurately find the best direction of light or would adding more sensors make the plant turn more smoothly and accurately? Why or Why not?
    10. How could you change the system so the plant turns slowly and smoothly instead of jumping to fixed angles like 0°, 90°, and 180° when the light changes?
    11. Can we use a DC motor instead of a servo motor for turning the plant? What changes will you make for that? Discuss