# 夜灯

## 第 1 步：制作

### 它是什么？

A nightlight that lights up your BBC micro:bit’s LED display in the dark.

### 编程指南

This project uses the micro:bit’s LEDs as a light sensor input to make a light that switches on automatically when it gets dark.

The micro:bit’s light sensor measures light in a range from 0 (very dark) to 255 (very bright).

### 工作原理

• An infinite loop in the code keeps the micro:bit checking light levels.
• It uses logic to decide whether to turn the LEDs on or off. A conditional instruction (if… then… else) makes the decision to turn the LED lights on or off.
• If the light level falls below 100, then it lights up the LEDs on the micro:bit’s display. Else (otherwise), it clears the screen to turn the LED lights off.
• Test it out by covering the display or shining a light on it, and see if the LEDs light up when it’s dark.
• You may need to change the 100 number depending on the light levels around you. Larger numbers will make the light come on more easily. Smaller numbers will make the light only come on when it’s very dark.

### 所需材料

• micro:bit或者是MakeCode模拟器
• MakeCode 或者 Python 编辑器
• 电池盒（选配）
• 光源和覆盖micro:bit的东西

## 第 2 步：编程

``````1from microbit import *
2
3while True:
5        display.show(Image(
6        "99999:"
7        "99999:"
8        "99999:"
9        "99999:"
10        "99999"))
11    else:
12        display.clear()
13    sleep(2000)
14``````

## 第3步：完善

• 更改图像以在黑暗的环境下显示月亮或星星。
• 将micro:bit装在你的包包或衣服上，以在步行或骑自行车时将其用作额外的安全灯 – 你能否使其闪烁以加强效果？
• Try this MakeCode project that makes the LED display get lighter and darker depending on the amount of light falling on the micro:bit. 你还能在其他地方看到以这种方式对光做出反应的事物吗？