Give the shield a voice

You will make a repeating pair of short notes. The first is 440 hertz and the second is 660 hertz. Which will sound higher? Does doubling a note’s duration make its pitch higher, or just make it last longer?

By the end, you should be able to control pitch, note length and silence independently.

Before you begin

Read milliseconds and know a function can receive a parameter.

Your goal: Call a function with a parameter. Show this with a prediction, a tested change and an explanation using the program’s names.

Retrieve one idea: what input, state or output did you change in the previous project?

Need a reminder? Make a button remember.

The onboard piezo sounder is connected to D3 through its removable jumper. With USB disconnected, check that the jumper joins both pins. Reconnect USB for programming. No external speaker is needed.

To work quietly, unplug USB before removing the jumper and keep it somewhere safe. The program and its LED indicator still work when the buzzer is disconnected.

The piezo element flexes when driven by a changing electrical signal. tone sets how quickly that signal repeats: frequency determines pitch. Its third argument limits how long the sound plays.

tone starts the sound and returns immediately. Our explicit wait lets that note finish before the next instructions stop it. A delay alone does not create a new note or change its pitch.

Read this part of the actual starter

void loop() {
  beep(440);
  beep(660);
  delay(800);
}

beep(frequency) is a reusable function. Its unsigned parameter receives 440 or 660 on each call. tone sets frequency and duration; the subsequent delays control when the next code runs. noTone stops output explicitly.

Work through one case

First beep: 120 ms tone + 80 ms gap. Second beep: another 200 ms. The final 800 ms pause makes the sequence approximately 1200 ms long.

Your turn: complete the trace

beep(660) puts ___ into frequency; the note lasts ___ ms and its following gap ___ ms.

If your answer differs

Separate the parameter in hertz from the constants in milliseconds.

Change only the second frequency to 880 and compare the interval. Next restore 660 and change NOTE_MS to 240; the notes become longer, not higher. Finally add beep(550); to invent a three-note “ready” signal.

Keep a record of the three frequencies and durations so a partner can reproduce your pattern.

Run a controlled experiment

Create a distinguishable three-note alert with a visual equivalent. Explain which value changes pitch and which changes duration.

1. Save a copy of the working starter. Reset the board so stored state begins from the declared values.
2. Write the expected result before editing. Change only the named factor; keep wiring and other settings fixed.
3. Edit the C++ in the editor, Verify, then Upload to the connected Uno. The starter simulation does not execute your edited C++.
4. Repeat the same input sequence. Record input, expected output, observed output and an explanation. Use labelled serial values where the sketch provides them.
5. If the result differs, inspect the relevant condition and pin before changing another factor. Restore and upload the saved starter to recover.

Core task: explain one changed case. Optional extension: choose a boundary or timing case and justify the extra test. Use a paper trace or annotated screenshot when physical manipulation is inaccessible; distinguish predictions from measurements.

Explain the difference between a 600-hertz note and a 600-millisecond note. Then change the long pause without changing either pitch.

• D12 flashes but there is no sound: inspect the buzzer jumper with power disconnected.
• Sound is continuous: keep both the note duration and noTone call.
• The program will not verify: make sure each call has parentheses, a comma between arguments, and a semicolon.

Independent check — try before revealing

If NOTE_MS becomes 200 and GAP_MS stays 80, how long is one call, and has pitch changed?

Frequency changes pitch, not volume. Provide a visual option and agree a comfortable classroom sound level.

If your explanation missed a condition or stored value, add that column to your trace and try a new input. A working upload alone does not answer this check.