# Case 08: Run Along the Black Line

## Purpose
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- The  [Cutebot](https://shop.elecfreaks.com/products/elecfreaks-micro-bit-smart-cutebot-kit-without-micro-bit-board?_pos=1&_sid=4c6909119&_ss=r) runs along the black line.

## Materials 
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- 1 x [Cutebot kit](https://shop.elecfreaks.com/products/elecfreaks-micro-bit-smart-cutebot-kit-without-micro-bit-board?_pos=1&_sid=4c6909119&_ss=r)
- 1 x Line-tracking Map(Homemade or enclosed in the  [Cutebot kit](https://shop.elecfreaks.com/products/elecfreaks-micro-bit-smart-cutebot-kit-without-micro-bit-board?_pos=1&_sid=4c6909119&_ss=r)

## Software Platform 
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[MicroSoft makecode](https://makecode.microbit.org/#)

## Programming
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### Step 1

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

![](./images/cutebot-pk-1.png)

- A codebase is required for  [Cutebot](https://www.elecfreaks.com/micro-bit-smart-cutebot.html) programming, click “Add Package” at the bottom of the drawer, search ` [Cutebot](https://www.elecfreaks.com/micro-bit-smart-cutebot.html)` in the dialogue box and download it.

![](./images/cutebot-pk-11.png)

***Note:*** If you met a tip indicating incompatibility of the codebase, you can continue with the tips or build a new project there.

### Step 2

- Choose "show icon" in the `On start`brick.

![](./images/case_01_02.png)

### Step 3

- Drag three `if` bricks into the `Forever` brick.
- Judge if the status of line-tracking sensors is  ○ ●, saying the left probe doesn't detect the black line while the right probe detects the black line.
- Set the left wheel speed to `50` and right to `25`,  make a right turn by the different speed of the two wheels and go back to the black line.
- Judge if the status of line-tracking sensors is  ● ○ and make a left turn to go back to the black line.
- When the status is ● ● that means the  [Cutebot](https://www.elecfreaks.com/micro-bit-smart-cutebot.html) runs along with the black line at the speed of `50`. 

![](./images/case_08_01.png)


### Programming

Links: [https://makecode.microbit.org/_1A0PqrDTDTp3](https://makecode.microbit.org/_1A0PqrDTDTp3)

You can also 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:https://makecode.microbit.org/_1A0PqrDTDTp3" frameborder="0" sandbox="allow-popups allow-forms allow-scripts allow-same-origin">
</iframe>
</div>  


## Result
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- The  [Cutebot](https://www.elecfreaks.com/micro-bit-smart-cutebot.html) runs along the black line and will adjust to run back to the black line if any deviation happens.

## Exploration
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- How to program to make the  [Cutebot](https://www.elecfreaks.com/micro-bit-smart-cutebot.html) run in the  white background of the map excluding the black line circle part? 

## FAQ
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## Relevant Files
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