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使用 millis 不调用 delay 实现闪烁

跟踪经过的时间，按计划运行任务

使用 millis 不调用 delay 实现闪烁 是 CoddyKit 上的免费 Arduino & IoT Academy 课时。 这是第 3 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。

A Built-in Stopwatch

The millis function returns how many milliseconds your board has been running since it powered on. It is a free, always-counting stopwatch. ⏱️

unsigned long now = millis();

Why unsigned long

Store millis in an unsigned long. The count grows huge over time, and a plain int would overflow in under a minute.

The Core Idea

Instead of pausing, you remember the last time you acted, then keep checking how much time has passed since then on every loop.

Remember the Last Moment

Keep a variable like previousMillis to store when you last toggled the LED. You will compare it against the current time each pass.

unsigned long previousMillis = 0;

Set Your Interval

Choose an interval, say 1000 milliseconds, as the gap between blinks. Acting only after this much time passes gives a steady rhythm.

const long interval = 1000;

Has Enough Time Passed

Each loop, subtract previousMillis from the current millis. If the gap is at least your interval, it is time to act.

if (millis() - previousMillis >= interval) {

Reset the Timer

The instant you act, set previousMillis to the current time. This restarts the countdown so the next blink waits a full interval again.

previousMillis = millis();

Flip the LED

Inside the timed block you simply toggle the LED, flipping it on if it was off and off if it was on, for a clean blink.

ledState = !ledState;
digitalWrite(ledPin, ledState);

The Loop Never Stops

Between blinks the loop keeps spinning at full speed, free to read sensors or buttons. Nothing is ever frozen waiting.

Subtraction Handles Overflow

After about 49 days millis wraps to zero, but the subtraction trick still gives the right gap, so your timing keeps working.

A Reusable Pattern

This millis pattern works for any repeating task, not just blinking. Change the interval and the action and you can schedule anything.

Quick Check

Why do we store the result of millis in an unsigned long?

Recap

You learned the millis pattern: remember the last time, check the elapsed gap, then act and reset. Now your board blinks while staying fully alert. 🎉

常见问题解答

「使用 millis 不调用 delay 实现闪烁」课时是免费的吗？

是的 — 「使用 millis 不调用 delay 实现闪烁」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 不调用 delay 实现闪烁」这节课中我会学到什么？

跟踪经过的时间，按计划运行任务 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 3 节课，共 4 节。

「使用 millis 不调用 delay 实现闪烁」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。

此课程中的所有课时

  1. Arduino 中的 int、float、bool
  2. 为什么 delay() 会阻塞一切
  3. 使用 millis 不调用 delay 实现闪烁
  4. 同时运行两项任务
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