11. Case 10: Speed Adjustable Car

11.1. Introduction

To make a speed adjustable car with a micro:bit.

../../_images/case_10_01.png

11.2. Quick Start

Materials Required

Nezha expansion board × 1

micro:bit × 1

Potentiometer × 1

Motors × 2

RJ11 wires × 1

Bricks details

../../_images/Bricks_case_10.png

Build the body parts of the car:

../../_images/case_10_02.png

Speed controller build-up

../../_images/case_10_03.png

Connection Diagram

  • Connect the potentiometer to J1, the two motors to M1&M4 on the Nezha expansion board as the picture shows.

../../_images/case_10_04.png

Assembly

  • Build a device as the picture shows:

../../_images/case_11_05.png

../../_images/case_11_06.png

../../_images/case_11_07.png

../../_images/case_11_08.png

../../_images/case_11_09.png

../../_images/case_10_13.png

../../_images/case_10_14.png

../../_images/case_10_15.png

../../_images/case_10_16.png

../../_images/case_10_17.png

../../_images/case_10_18.png

Video reference: https://youtu.be/bVa5-wrcoeA

11.3. MakeCode Programming

Step 1

Click “Advanced” in the MakeCode to see more choices.

../../_images/case_01_10.png

For programming, we need to add a package: click “Extensions” at the bottom of the MakeCode drawer and search with “PlanetX” in the dialogue box to download it.

../../_images/case_01_11.png

For programming, we need to add a package: click “Extensions” at the bottom of the MakeCode drawer and search with “nezha” in the dialogue box to download it.

../../_images/case_03_09.png

Notice: If you met a tip indicating that some codebases would be deleted due to incompatibility, you may continue as the tips say or create a new project in the menu.

Step 2

Code as below:

../../_images/case_10_19.png

Reference

Link：https://makecode.microbit.org/_cTDgmegXA5ip

You may also download it directly below:

---

Result

  • The speed of the car could be adjusted by the potentiometer.