Project 15 Button Controls Servo

1. Description

In the previous project, we learned how to control the servo automatically. In this project, we are going to use the A/B buttons on the Micro:bit mainboard to manually control the rotation of the servo. This mimics how we might control a robot arm using a remote controller.

Button A: Controls rotation in one direction.
Button B: Controls rotation in the opposite direction.

2. Wiring Diagram

3. Test Code

1. Preparations

Insert the Micro:bit into the robot arm’s 16-channel servo shield.
Connect the external power supply.
Connect the Micro:bit to your computer via a Micro USB cable.
Open the MakeCode editor (web or offline version).

Import Hex file, or drag the code manually (add the pca9685 extension first).

2. drag the code manually

Add pca9685 Extension

⚠️ Prerequisite: This project requires importing a specific extension to function. If you are new to this or unsure how to import extensions, please refer to our “General Guide on Importing Micro:bit Extensions” first. Once you are familiar with the process, please return to this tutorial.

Extensions_URL: https://github.com/keyestudio2019/pxt-pca9685-smallest

(Note: The code block above is for display. Please ensure the logic matches: On Button A pressed -> Servo write 0; On Button B pressed -> Servo write 180, or specific angles as required.)

3. Import Hex file

To import the Hex file directly, please locate the downloaded Hex file and drag it into the editor.

🏡Click to download the code for this lesson

After downloading the code, simply drag it directly into the coding area to upload it. (Note: The image below is for demonstration purposes only—please drag in the code you downloaded for this lesson above.)

4. Test Result

Download the code to the Micro:bit and power on using external power. Press the reset button on the Micro:bit board.

Then:

Press Button A → Servo 2 rotates to the left (e.g., 0°).
Press Button B → Servo 2 rotates to the right (e.g., 180°).