Face Detection

Face detection has a wide range of application, we will learn how to do face detection in this tutorial.


Detecting Faces


Load KOI Extension: https://github.com/KittenBot/pxt-koi

Loading Extensions

Blocks for face detection:


Sample Program:


Program Flow

Download the program to the Micro:bit, the pixel on the Micro:bit 把程式下載到Microbit上,可以看到Microbit的點陣隨著人臉的移動而移動。


Mapping coordinates

We can use the map function to map a value to a new range.


Sample Code

Face Detection (Extension0.5.7)

Extension Version and Updates

There may be updates to extensions periodically, please refer to the following link to update/downgrade your extension.

Makecode Extension Update


1: There is no reaction after pressing the buttons on the Micro:bit.

· A: This is because KOI has a longer boot time than Micro:bit. When the power is turned on, Micro:bit has already ran the code for KOI initialization before KOI is ready.

· Solution: Reset your Micro:bit after KOI has been turned on. (The trick is to let KOI power on completely before initialization.)

2: Does KOI work with 3V input?

· A: No, KOI only works with 5V.