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使用 millis() 消抖

用短暂的稳定时间窗口过滤噪声

使用 millis() 消抖 是 CoddyKit 上的免费 Arduino & IoT Academy 课时。这是第 2 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Arduino & IoT Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Arduino & IoT Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Why Not Just delay()?

You could pause with delay() after a press, but that freezes your whole board. The smarter tool for clean buttons is millis().

millis() Is a Stopwatch

millis() returns how many milliseconds your board has been running. You compare two readings to measure elapsed time without stopping.

unsigned long now = millis();

The Debounce Plan

The idea is simple: when the pin changes, start a timer. Only trust the new state if it holds steady past a short window.

Pick a Debounce Window

A delay of about 50 milliseconds is the classic choice. It's long enough to outlast bounce, yet far too fast for you to notice.

const unsigned long DEBOUNCE = 50;

Remember the Last Change

You need a variable to store when the pin last flipped. Compare it to the current time on every loop pass.

unsigned long lastChange = 0;

Track Two States

Keep the raw reading and the confirmed stable state separately. The raw one is noisy; the stable one is what your logic trusts.

int lastRaw = HIGH;
int stable = HIGH;

Detect a Flip

Each loop, read the pin. If it differs from the last raw value, the signal just moved, so reset your timer.

int raw = digitalRead(BTN);
if (raw != lastRaw)
  lastChange = millis();

Wait for Stillness

If enough time has passed since the last flip, the reading has settled. Now it is safe to accept it as the real state.

if (millis() - lastChange > DEBOUNCE) {
  stable = raw;
}

Act on the Edge

To fire once per press, watch for the stable state changing to LOW. That single edge is your clean, debounced press.

if (stable == LOW && lastStable == HIGH)
  Serial.println("clean press");

Update for Next Time

At the loop's end, save the current readings into your last variables. This keeps the comparison fresh on every pass.

lastRaw = raw;
lastStable = stable;

Non-Blocking Wins

Because millis() never pauses the board, your sensors and outputs keep running. You debounce while everything else stays alive. 🚀

Quick Check

Let's check how millis() debouncing decides a press is real.

Recap: Clean Presses

You used millis() to ignore bounce without freezing the board, accepting a press only once it settles. Solid, professional input! ✅

常见问题解答

「使用 millis() 消抖」课时是免费的吗？

是的 — 「使用 millis() 消抖」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Arduino & IoT Academy 课程的其余内容，请升级到 CoddyKit PRO。 Arduino & IoT Academy 课程共包含 4 节课。

「使用 millis() 消抖」这节课中我会学到什么？

用短暂的稳定时间窗口过滤噪声你通过在浏览器中直接运行的动手代码来练习 Arduino & IoT Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Arduino & IoT Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Arduino & IoT Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 2 节课，共 4 节。

「使用 millis() 消抖」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Arduino & IoT Academy 课中编写并运行代码吗？

能。每节 Arduino & IoT Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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