In this article, you will learn:
1. How to use 3D printing to create a micro:bit box with a battery compartment
2. How to create a Pomodoro timer (25-minute countdown alarm) with micro:bit
The micro:bit is a micro-programmable computer launched by the BBC in collaboration with many companies, designed to allow every child to start programming without any prior knowledge of programming languages. For more information, please refer to our previous article on creating a usable compass with micro:bit.
Generally, we go to https://makecode.microbit.org to do web programming. After writing the instructions, we can download them to the micro:bit drive or copy the hex file to the drive.
This time, we will use 3D design software to create a universal box for the micro:bit with a battery compartment, leaving space for two buttons, a display screen, a computer interface, an external battery box interface, and a reset button.
With a universal box, we can program the micro:bit to create various applications. For instance, we will create a Pomodoro timer that starts a 25-minute countdown when button A is pressed, sounds an alarm when the time is up, and stops the alarm when button B is pressed.
Materials and Tools List
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micro:bitMain control board
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Data cable
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Buzzer
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2 AA batteries
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Online programmingwebsite, such as https://makecode.microbit.org
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3D printer and materials
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Aluminum foil and scissors, or wires, solder, and soldering iron
Designing a Universal Box for micro:bit
We used 123D software to create a micro:bit box that can hold the micro:bit board and be powered by 2 AA batteries. The surface of the box has openings for the display, two buttons, the computer interface cable, and the external battery box interface, and has reserved positions for the battery switch and the buzzer.
As shown, the positive terminal of the buzzer connects to pin 0 of the board, and the negative terminal connects to GND.
For the internal circuit connections of the box, we used aluminum foil. When choosing aluminum foil, use the side without glue for the circuit connection. Alternatively, you can use wires and solder them with a soldering iron.
Practical Case of the Universal Box: Pomodoro Timer
The program’s function is to implement a Pomodoro timer. Press button A to start a 25-minute countdown, displaying the elapsed minutes on the screen every minute. At 25 minutes, the buzzer sounds, and pressing button B stops the buzzer/stops the timer. Press button A again to restart the timer. Pressing buttons A and B together changes the countdown time, defaulting to 25 minutes, increasing by one minute with each press, up to a maximum of 30 minutes, after which it resets to 1 minute.
The Pomodoro Technique is a time management method created in the 1980s that uses a timer to break work into 25-minute intervals followed by 5-minute breaks. These intervals are called pomodori, the plural of the Italian word pomodoro (tomato).
There are 5 basic steps:
Decide on the task to be completed
Set the timer for n minutes (usually 25)
Work until the timer goes off, marking an X
Take a 3-5 minute break
After four Xs, take a 15-30 minute break
Future Improvements
The switch position in the 3D model is currently at the bottom of the box. However, since the box is usually placed upright when used as an alarm clock, the switch may affect its placement. We will move the switch to the back of the box in the future. Additionally, when using aluminum foil, there may sometimes be contact issues, making it difficult for the switch to work properly. These can all be improved later. We also hope that teachers can create more fun projects using this box.
Recently, we have launched a series of tutorials on micro:bit. Click the link to learn more:
Create a mobile music remote control with micro:bit
Create a usable compass with micro:bit
Create a Morse code telegraph with micro:bit and 3D printing
Click “Read More” at the end of the article to download the 3D model file for the micro:bit box and the source code for the Pomodoro timer, for reference only.
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