### Project 8：Light Detection

![](./media/Python_b855274f.png)

1\.  **Description**

In this project, we will focus on the light detection function of the Micro: Bit main board. It is achieved by the LED dot matrix since the main board is not equipped with a photoresistor.

2\.  **Preparation**

A. Attach the micro:bit main board to your computer via the USB cable

B. Open the offline version of Mu.

3\.  **Test Code**

Enter Mu software and open the file“Detect Light Intensity by Microbit\.py”to import the code. You can also input code in the edit window yourself.

(**Note: All English words and symbols must be written in English.**)

![](./media/Python_b4f06503.png)

```python
from microbit import *

while True:

    Lightintensity = display.read_light_level()

    print("Light intensity:", Lightintensity)

    sleep(100)
```
Click“Check”to examine errors in the code. The program proves wrong if underlines and cursors are shown. 

![](./media/Python_b41eeb0f.png)

If the code is correct, connect the micro:bit to your computer and click“Flash”to download code to the micro:bit board.

![](./media/Python_7baa2190.png)

4\.  **Test Result**

After downloading the code to the board successfully, **power on via micro USB cable or external power supply(turn the DIP switch to ON)**. Click“REPL”and press the reset button on micro:bit.

![Img](./media/Python_bb3e1312.png)

Then REPL window will show the light intensity value, as shown below.

When the LED dot matrix is covered by hand, the light intensity showed is approximately 0; when the LED dot matrix is exposed to light, the light intensity displayed gets stronger with the light.

![](./media/Python_778d89d6.png)

5\.  **Code Explanation**

![Img](./media/Python_dcdc4536.png)