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Week 4 — Variables & Thresholds with Sensors
Focus Concept: Variables & Thresholds
Mini-Project: Smart Plant Monitor (light + temperature sensors)
Objectives
- Understand what a variable is in coding.
- Learn what a threshold means and how it controls decisions.
- Explore how the light and temperature sensors on the micro:bit work.
- Create a simple monitor that warns when it’s too dark or too cold.
Success Criteria
- I can explain what a variable is and why it’s useful.
- I can use a variable to store a sensor value.
- I can compare sensor values with a threshold.
- I can make the micro:bit give a warning when the threshold is crossed.
Key Vocabulary
- Variable — a “box” in memory that stores a value which can change.
- Threshold — a limit or boundary we compare against (e.g. “if temp < 15°C”).
- Sensor — a device that measures something from the environment, like light or temperature.
- Input — information coming into the micro:bit (e.g. from a sensor).
- Output — how the micro:bit reacts (e.g. LEDs, sound, message).
- Logic — rules that decide what happens (e.g. if…then…else).
- Loop — instructions that repeat automatically. A loop can run forever or stop when a condition is met.
Resources
- Micro:bit MakeCode: link
- Simple times tables quiz: MakeCode Code
- Sensor overview (light, temp): link
- How temperature affect plants: Short ¦ In depth
- KS3 Photosynthesis: video
- Generating beautiful patterns using times tables: video
- The Map of Mathematics: video
- The Surprising map of plants: video
Equipment
- BBC micro:bits + USB cables.
- Chromebooks with internet access.
Safety & Setup Notes
- Sensors are built-in, no extra hardware needed.
- Avoid touching USB ends with damp hands (remind pupils as “plant monitor” is discussed).