Micro:bit Project 03 – Speed Control Fan – Information Technology Course

01

Overview

1.1 Introduction

Summer is here, and the weather is a bit hot. Let’s make a small fan with the micro:bit to help cool us down.

1.2 Course Objectives

• 【Scientific Knowledge】Understand the difference between analog signals and digital signals.
• 【Programming Knowledge】Master the use of functions.
• 【Hardware Knowledge】Master the control methods of motors, including: forward, reverse, stop, accelerate, and decelerate.

02

Item List

Small particle building blocks	Several
micro:bit main board	x 1
micro:bit expansion board	x 1
Motor driver module	x 1
M motor	x 1
5V power box	x 1
Power cable	x 1
2P DuPont wire	x 2

03

Assembly Process

04

Program Explanation

4.1 Wiring

• LEGO power cable: One end is a LEGO quick connector, connected to the power box; the other end is a DC head, plugged into the DC port of the expansion board.
• Red and black 2P DuPont wire: One end connects to the power of the expansion board, red connects to 5V, black connects to GND; the other end connects to the motor driver module, black connects to G, red connects to V.
• Blue and white 2P DuPont wire: One end connects to the P0 and P1 pins of the expansion board; the other end connects to the A1 and A2 pins of the motor driver module.
• The motor plug: Insert into the MotorA interface of the motor driver module.

Note: The red connects to the positive terminal, and the black connects to the negative terminal; do not connect them incorrectly, as it may damage the main board. If it feels hot, quickly cut off the power.

4.2 Program 1: Make the Fan Spin

Program Explanation:

By sending corresponding signals to A1 and A2, the motor will start running.

Forward: Write digital signal 1 to P0, and digital signal 0 to P1.

Reverse: Write digital signal 0 to P0, and digital signal 1 to P1.

Stop: Write digital signal 0 to P0, and digital signal 0 to P1.

4.3 Program 2: Control the Speed of the Fan

Program Explanation: By writing analog signals to the corresponding pins, speed control can be achieved. Here we used a function to encapsulate the motor operation, monitorRun is the function name, speed is the speed value from 0 to 1023, reverse equals true for forward, and reverse equals false for reverse.

4.4 Program 3: Three-Speed Fan

Program Explanation:

Set three speed values: low speed = 300, medium speed = 600, high speed = 1000.

The default start is -1, and the fan does not spin.

When button A is pressed, the gear increases by 1, and the speed increases; when in high speed gear, pressing button A again stops the fan.

When button B is pressed, the gear decreases by 1, and the speed decreases; when in low speed gear, pressing button B again stops the fan.

05

Product Display

Students who need accessories can go to my Taobao store with the same name to purchase.