## 3.2.5 Flywheel Bike

---------------

### 3.2.5.1 Overview

![Img](./media/top1.png)

Here we build a flywheel bike with a Micro:bit V2 board, a servo expansion board, two 360° LEGO servos and some LEGO parts. We program to control it to move through the Micro:bit V2 buttons A and B.

![Img](./media/bottom1.png)

---------------

### 3.2.5.2 Materials Required

![Img](./media/A5-0.png)

---------------

### 3.2.5.3 Installation Steps

![Img](./media/2top.png)

![Img](./media/A5-1.png)

![Img](./media/A5-2.png)

![Img](./media/A5-3.png)

![Img](./media/A5-4.png)

![Img](./media/A5-5.png)

![Img](./media/A5-6.png)

![Img](./media/A5-7.png)

![Img](./media/A5-8.png)

![Img](./media/A5-9.png)

![Img](./media/A5-10.png)

![Img](./media/A5-11.png)

![Img](./media/A5-12.png)

![Img](./media/A5-13.png)

![Img](./media/A5-14.png)

![Img](./media/A5-15.png)

![Img](./media/A5-16.png)

![Img](./media/A5-17.png)

![Img](./media/A5-18.png)

![Img](./media/A5-19.png)

![Img](./media/A5-20.png)

![Img](./media/A5-21.png)

![Img](./media/A5-22.png)

![Img](./media/A5-23.png)

![Img](./media/A5-24.png)

![Img](./media/A5-25.png)

![Img](./media/A5-26.png)

![Img](./media/A5-27.png)

![Img](./media/A5-28.png)

![Img](./media/A5-29.png)

![Img](./media/A5-30.png)

![Img](./media/A5-31.png)

![Img](./media/A5-32.png)

![Img](./media/A5-33.png)

![Img](./media/A5-34.png)

![Img](./media/A05.png)

![Img](./media/wiring5.png)

![Img](./media/A5-35.png)

![Img](./media/A5-36.png)

![Img](./media/A5-37.png)

![Img](./media/A5-38.png)

![Img](./media/A5-39.png)

![Img](./media/A5-40.png)

![Img](./media/A5-41.png)

![Img](./media/2bottom.png)

---------------

### 3.2.5.4 Test Code

<span style="color: rgb(255, 76, 65);">The speed values of 40 and 100 in the code can be adjusted according to your needs.</span>

![Img](./media/couj05.png)

⚠️ **<span style="color: rgb(255, 76, 65);">Special reminder: You can obtain the sample code through the following two methods.</span>**

#### **Method 1: drag and drop code blocks to build the sample code**

**1. MakeCode programming environment**

The online version of MakeCode: <u>[MakeCode editor](https://makecode.microbit.org/#editor)</u>

**2. Makecode extension library**

⚠️ **<span style="color: rgb(255, 76, 65);">Special reminder: </span>** Copy and paste the link: `https://github.com/keyestudio2019/pxt-creative-inventors-kit-master.git` into the search box to import the library.

![Img](./media/Animation-4.gif)

**3. Write the sample code**

![Img](./media/dongtu-05.gif)

#### **Method 2: download the sample code file directly**

**1. Download the code file**

Click to download the code file: <u>[3_3_5_Flywheel_Bike](./Codes/3_3_5_Flywheel_Bike.hex)</u>

**2. MakeCode programming environment**

The online version of MakeCode: <u>[MakeCode editor](https://makecode.microbit.org/#editor)</u>

**3. Load the sample code**

Drag and drop the sample code to the MakeCode editor.

![Img](./media/Animation-0001.gif)

![Img](./media/line1.png)

---------------

### 3.2.5.5 Test Result

![Img](./media/4top.png)

Wire up and power on through Micro USB cable, and connect an external power source (four AAA-1.5V batteries installed in the battery box, ensuring sufficient power).

To download the sample code using an online browser, you need to send the downloaded "**.hex**" file to the Micro:bit V2 board. There are two ways as follows:  

**① Download through WebUSB**

For browsers like **Google Chrome / Microsoft Edge**, you need to click "**Connect Device**" to pair the device first. After that, click "**Download**" to load the sample code to the Micro:bit V2 board.

![Img](./media/Animation-05.gif)

**② Download without WebUSB**

For browsers like **Safari / Firefox / Other**, download and send the sample code to the Micro:bit V2 board.

![Img](./media/Animation-005.gif)

After downloading the sample code, unplug the Micro USB cable to the Micro:bit V2 board.

Turn the DIP switched to the RGB and ON.

![Img](./media/CBA01.png)

Press button A on the Micro:bit V2 board and release it, the flywheel bike moves with its flywheel spinning, these SK6812 RGB LEDs emit colorful light and the 5×5 LED matrix displays ![Img](./media/ab3.png).

Press button B on the Micro:bit V2 board and release it, the flywheel bike and its flywheel stop, and these SK6812 RGB LEDs and the 5×5 LED matrix turn off.

![Img](./media/dongtu-005.gif)

![Img](./media/4bottom.png)

---------------