Micro:bit Decision Maker

Overview

Students are introduced to the micro:bit by designing and testing a simple “weather advice” program. They will use input, variables, branching and iteration to make a digital system respond to data. Unplugged planning and paired roles ensure students can participate regardless of prior access to technology at home.

Learning intentions

Students will:

• understand that an algorithm is a precise sequence of instructions
• design an algorithm using input, a variable, branching and iteration
• implement and test a visual program on a micro:bit
• communicate design decisions using appropriate technical language
• work safely and collaboratively with unfamiliar technology

Success criteria

• I can explain what input, variable, condition, branch and loop mean.
• I can design steps that respond differently to at least two possible inputs.
• I can create and run a micro:bit program that gives appropriate feedback.
• I can test my program, identify an error and improve it.

Curriculum links

• Digital Technologies: design algorithms involving multiple alternatives and iteration.
• Digital Technologies: implement algorithms as visual programs involving control structures, variables and input.
• Design and Technologies: generate, iterate and communicate design ideas using technical terms and graphical representations.
• NSW Technology Mandatory Stage 3: designing, producing and evaluating digital solutions collaboratively.

Lesson structure (60 minutes)

1. 0–5 min · Hook and context. Open with the hook and learning goals and show a micro:bit displaying a happy or concerned face. Ask, “How could this small device decide what advice to give?” Students make a prediction with a partner and share examples of digital systems that respond to data.

2. 5–13 min · Explicit teaching and demonstration. Use the key vocabulary and worked example to introduce input, variable, condition, branch, loop and output. Model the algorithm: “Ask for the soil moisture value; store it in moisture; if moisture is less than 30, show ‘WATER’; otherwise show ‘OK’.” Explain that the micro:bit’s buttons, shake gesture or radio message can provide input. Demonstrate a simple MakeCode program using button A as input: when A is pressed, set moisture to 20, then show “WATER” if it is below 30, otherwise show “OK”. Students identify the input, variable, condition and two possible outputs using hand signals.

3. 13–23 min · Unplugged algorithm design. Distribute the micro:bit algorithm planning sheet. Students work in pairs to plan a “rural garden helper” program using this structure: input → store value in a variable → decision → output. They choose one input method—button A, button B, shake or a number supplied by the teacher—and complete a flowchart or numbered algorithm. Example: “When button A is pressed, set rain to 10. If rain is less than 20, show a water-drop icon. Otherwise, show a sun icon.” Circulate and ask, “What happens in the other branch?” and “What should happen if the input changes?”

4. 23–40 min · Guided programming. Organise 19 students into pairs, with one triad if required. Provide one micro:bit and computer or tablet per pair where available. Students use MakeCode to build their planned program, initially copying the teacher’s structure and then changing the variable name, value, condition and images or messages. Students without a device at a particular moment act as “code reviewers”, checking the worksheet against the screen; rotate roles every five minutes: driver, navigator and tester. Students should first test fixed inputs, then add a loop such as “repeat 3 times” to display the advice or collect three button presses.

5. 40–51 min · Test, debug and improve. Refer to the testing checklist and debugging prompts. Pairs predict the expected behaviour before running the program, then test both branches. They record one result on the worksheet: “When ___ happens, I expected ___, but ___ occurred.” Model debugging by deliberately changing < 30 to > 30, asking students to locate the error and explain the correction. Each pair makes at least one improvement, such as changing the threshold, adding a clearer icon or repeating the output.

6. 51–57 min · Pair share and evaluation. Invite three or four pairs to demonstrate their micro:bit or simulated program. Students explain their input, variable, condition, outputs and any loop. Classmates give one specific comment using the prompts on the demonstration and feedback slides: “The program responds well when…” and “A useful improvement could be…”

7. 57–60 min · Exit reflection. Students complete the final section of the micro:bit algorithm planning sheet: define one key term, name one bug they found or could find, and complete “A variable is useful because…”. Collect worksheets as evidence of algorithm design and understanding.

Resources

• Micro:bits, USB cables and battery packs
• Computers or tablets with MakeCode installed
• the micro:bit introduction and teaching deck
• the micro:bit algorithm planning sheet
• Projector or interactive display
• Headphones if available
• Board and markers
• Device labels and charging/storage container

Assessment

• During modelling, check whether students can identify input, variable, condition, branch and output in the worked example.
• Review pair plans and question whether both branches are complete and logically connected to the input.
• Observe testing and debugging. Use the worksheet and exit reflection to assess whether students can predict behaviour, locate an error and describe an improvement.

Differentiation

• Support students with a partially completed flowchart, a word bank, icon choices and sentence starters such as “If the value is…, then…” Pair students strategically and keep the driver/navigator roles explicit.
• For students with limited prior technology experience, use the unplugged algorithm first and provide a starter MakeCode file or teacher-created block sequence. Allow simulation on screen when a physical micro:bit is unavailable.
• EAL/D students may explain ideas through labelled diagrams, gestures and oral rehearsal before writing. Read instructions aloud and display each block sequence visually.
• Extend confident students by adding a third outcome using if/else if, collecting several inputs in a loop, or changing the program so it calculates an average before making its decision.