# Case 27: The Distance Indicator

## Introduction 

This is a distance detection device. In order to prevent the spread of the epidemic, people should maintain a certain social distance in public. This device can display the distance between the carrier and the person in front of it on the screen.

![](./images/case_27_01.png)

## Quick Start 



### Materials Required


Nezha expansion board × 1

micro:bit V2 × 1

sonar sensor  × 1

Bricks × n

***Tips: You may need to purchase [Nezha Inventor's Kit](https://shop.elecfreaks.com/products/elecfreaks-micro-bit-nezha-48-in-1-inventors-kit-without-micro-bit-board?_pos=2&_sid=ed1b6fbd2&_ss=r) if you want all the above compoents.***

### Connection Diagram 

Inset the micro:bit, and connect the sonar:bit to J1 port on Nezha expansion board. 


![](./images/case_27_03.png)



### Assembly Video


Video link: [https://youtu.be/0HgP_YVgNJU](https://youtu.be/0HgP_YVgNJU)

<iframe width="560" height="315" src="https://www.youtube.com/embed/0HgP_YVgNJU" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>


### Assembly Steps

![](./images/case_step_27_01.png)

![](./images/case_step_27_02.png)

![](./images/case_step_27_03.png)

![](./images/case_step_27_04.png)

![](./images/case_step_27_05.png)


## MakeCode Programming 



### Step 1


Click "Advanced" in the MakeCode drawer to see more choices. 

![](./images/case_01_10.png)




We need to add a package for programming. Click "Extensions" in the bottom of the drawer and search with "nezha" to download it. 

![](./images/case_03_09.png)

***Note:*** If you met a tip indicating the codebase might be deleted due to incompatibility, you may continue as the tips say or create a new project in the menu. 

### Step 2


### Programme as the pictures indicate


![](./images/case_27_10.png)



### Reference

Link: [https://makecode.microbit.org/_Vb69KzLR3Dhe](https://makecode.microbit.org/_Vb69KzLR3Dhe)

You may download it directly below: 

<div style="position:relative;height:0;padding-bottom:70%;overflow:hidden;"><iframe style="position:absolute;top:0;left:0;width:100%;height:100%;" src="https://makecode.microbit.org/#pub:_Vb69KzLR3Dhe" frameborder="0" sandbox="allow-popups allow-forms allow-scripts allow-same-origin"></iframe></div>  


### Result
After powering on, the detected distance displays on the micro:bit. 

![](./images/case-gif-27.gif)