# 3.32 Ultrasonic Ranger

## 3.32.1 Overview

In this project, we combine the ultrasonic sensor and the OLED module to build a distance meter, whose detection range is 4-300CM.

## 3.32.2 Test Code

### 3.32.2.1 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 `3-32-rangeFinder.sb3`

**Manually build blocks:**

1. Build the two basic blocks:![6-1-4-1-1](./media/6-1-4-1-1.png)
2. Initialize OLED module by ![j53](./media/j53.png)
3. Add a ![j54](./media/j54.png) and set text size to 12x16
4. Declare a variable *distance* and assign the value detected by the ultrasonic sensor to *distance*

![QQ_1722046131988](./media/6-32-2-1-1.png)

5. Add a ![j58](./media/j58.png) to clear the logo displayed on OLED

6. Add an OLED module to display “Distance:” on the first line and show the value of *distance* on the second line. Add the unit of “CM” after the value. 

7. At last, add a refresh block.

   ![QQ_1722046707083](./media/6-32-2-1-2.png)

**Complete Test Code**

![6-32-1-2](./media/6-32-1-2.png)

### 3.32.2.2 Test Result

After uploading code, “Distance:” will be displayed on the first line. What followed is the distance value in “CM” in the second line.

![6-32-2-2](./media/6-32-2-2.png)