# 3.24 Button Control Fan

## 3.24.1 Overview

In this experiment, we program to control the fan by a button.

## 3.24.2 Test Code

### 3.24.2.1 Code Flow

![6-24-2-1](./media/6-24-2-1.png)

### 3.24.2.2 Build Code

There are two ways to upload the code: directly open the code file we provide; or manually build blocks.

**Directly open the code file we provide:**

1. Click ![](./media/j68.png) and choose `Load from your computer`

![](./media/j67.png)

2. We have already downloaded the codes on computer desktop, so open the file and choose `3-24-electricFan.sb3`

**Manually build blocks:**

1. Build the two basic blocks:

![6-1-4-1-1](./media/6-1-4-1-1.png)

2. Declare a variable and name to *item*, and assign the analog value read by ADKey to it.

![](./media/6-24-2-2-1.png)

3. Add a ![j25](./media/j25.png) to determine the value of *item*. When item > 3500 (the red button is pressed), the fan stops. When item > 2000 & item < 3000 (the yellow button is pressed), the fan rotates.
3. At last, add a delay of 0.3s.

![6-24](./media/6-24-2-2-2.png)

**Complete Test Code**

![6-24](./media/6-24-2-2-3.png)



### 3.24.2.3 Test Result

After uploading code, when we press the yellow button, the fan will turn on. When we press the red button, the fan stops working.