Scanning Barcodes and QR Codes

· Barcode is wide adopted in our daily lives, they are found on various products.

· QR Codes are used for data exchange or cashless shopping.

Scanning Barcodes and QR Codes


Load KOI Extension:

Loading Extensions

Blocks for reading codes:


Sample Program


Program Flow

Download the program to the Micro:bit.

  1. Point the KOI at a Barcode and press A on the Microbit, the content of the Barcode will be shown on KOI’s screen.

  2. Point the KOI at a QRCode and press B on the Microbit, the content of the QRCode will be shown on KOI’s screen.

Advanced Program

There may not be enough time to read the contents if we show it on KOI, to improve readability, we can connect an OLED screen.

Connecting an OLED

Connect an OLED panel to the I2C port of your Robotbit/Armourbit.


Sample Program

Load the extension for OLED:


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.

3: KOI fails to recognize my Barcodes/QR Codes.

· A: Make sure the width of the code is at least 3.5cm and the code is entirely within the camera’s view.