Wireless Radio Basics

Overview

Students connect real-world wireless communication to the Micro:bit radio feature by modeling message sending/receiving. The lesson then moves into MakeCode with a two-way message sender that shows received text on the LED grid. Throughout, students interpret “opposites” and “distance on a number line” to reason about signal strength and message delivery as understandable numerical ideas.

Learning intentions

Students will be able to:

• Explain how radio communication uses shared rules (radio groups) to prevent mixed messages.
• Describe signal strength as a measurable idea (e.g., strong vs. weak) and relate it to “distance” concepts.
• Interpret incoming messages as rational-number data (e.g., signal strength values) and explain what opposite values mean in context.
• Build a MakeCode program that sends a text message and displays the received text.

Success criteria

• I can state what a radio group does and why it matters for sending/receiving correctly.
• I can explain how signal strength affects whether messages are received, using “distance” language.
• I can identify what “opposite” quantities mean in a signal context (for example, +strength vs. –strength or strong vs. weak).
• I can write a working two-way radio program that displays received text on the LED grid.

Curriculum links

• The Number System — additive inverses and interpreting sums in real-world contexts (opposites combine to 0).
• The Number System — subtraction as adding the additive inverse, and interpreting distance as absolute value of a difference.
• The Number System — division sign rules interpreted in context (if used when modeling signal/no-signal thresholds).
• The Number System — extending multiplication to signed numbers and interpreting products in context (optional reasoning when comparing strength changes).

Lesson structure (45 minutes)

1. 0–5 min · Hook (unplugged). Teacher shows two sealed “mail boxes” labeled A and B, and a set of message cards with numbers for signal strength (e.g., 3, 1, 0, -1). Students quickly predict which box will “receive” each card when a “radio group” key is matched.
2. 5–12 min · Mini lesson: how wireless works. Teacher explains: radio groups act like shared stations; messages are sent as packets; devices listen and filter for the group. Students take 3 quick notes on: group rules, packets, and why interference happens.
3. 12–20 min · Unplugged simulation (signal strength & distance). Teacher sets up two zones on the floor: “near” and “far.” Students work in pairs: one is the sender, one is the receiver. The sender “broadcasts” a packet card that includes a signal value. The receiver accepts it only if the signal meets the threshold.

• Teacher pauses and draws a simple number line on the board, asking: “If our distance from the sender is larger, what happens to signal? How could absolute value represent how far apart we are?”
• Students answer using one sentence each: “Distance affects delivery because the difference/absolute value changes.”

4. 20–28 min · Micro:bit connection (radio blocks preview). Teacher demonstrates a MakeCode radio setup at the front: choose a radio group, send a message, and handle incoming messages to display them on the LED grid. Students turn and talk: “What block pairs match sender vs. receiver?”
5. 28–38 min · Build: two-way message sender (MakeCode). Students build the program:

• Set radio group (same on all devices).
• On button press (A or B): send a short text message (e.g., “HI”).
• On radio received: store the received text and display it on the LED grid (using basic text/LED options available in the class environment). Teacher circulates with a checklist: radio group matches, send block triggers, receive event runs, display updates.

6. 38–43 min · Test & troubleshoot. Students swap roles with another pair and test: “near vs. far,” “matching vs. non-matching radio groups.” Teacher prompts students to explain one fix using number language: “We needed the distance/difference to be small enough” or “Opposites cancel to 0 in our model.”
7. 43–45 min · Exit ticket. Students answer 2 prompts:

• “What does a radio group do?”
• “In one sentence, explain how signal delivery relates to distance/difference and why opposite values might represent weak vs. strong.”

Resources

• Micro:bits with USB cables
• MakeCode (class accounts or offline access as used by the school)
• LED display reference printout (what the chosen letters/symbols look like)
• Unplugged materials: message cards (some labeled with signal values like 3, 1, 0, -1), two “mail boxes,” floor tape for near/far zones
• Student handout: radio checklist (group, send trigger, receive display)
• Timer for pair rotations

Assessment

• During simulation: teacher listens for students using “distance/difference” and “absolute value” language to justify why messages did/did not arrive.
• During building: quick observation checklist for correct radio event flow (send → received handler → display).
• Exit ticket: radio group explanation + one-sentence number/context connection (distance/opposites).

Differentiation

• Support:
• Provide sentence starters: “Radio group keeps messages from ___.”
• Offer a pre-made MakeCode template with only the message text and group number to change.
• Use a word bank: packet, group, signal strength, near, far, receive, display.
• Extension:
• Challenge students to add a simple “signal strength comment” by displaying a symbol depending on received signal value (e.g., show a checkmark when strong, an X when weak).
• EAL/SEN:
• Allow verbal responses or drawing for the exit ticket first draft; teacher can then prompt for one completed sentence.
• Pair students strategically so a confident builder supports the partner’s navigation of blocks.