QR code reader – i2c

Tiny Code Reader: QR code reader on an I2C bus

Useful Sensors’ Tiny Code Reader is a tiny, low-cost hardware module capable of reading QR codes. It is designed to be a simple way to provision a system, such as by providing the Wi-Fi network name and password or by providing input when a keyboard is not available.

The Tiny Code Reader board incorporates an image sensor and a small microcontroller, but these are not visible, making it easier to integrate into various projects. The board returns information on all QR codes it detects via an I2C connection.

The board uses a standard STEMMA QT / Qwiic connector for the I2C interface. If you are using a standard connector, the wire colours are yellow for SCL, blue for SDA, red for 3.3V and black for GND. The sensor supports I2C bus speeds of up to 400k baud with a 3.3 V power supply. Please note: other voltage levels (such as 5V) are not supported.

Remember to ensure that the target has a clear line of sight, as the sensor in this QR code reader uses an internal image sensor. The board can be mounted in any orientation, which should not affect the quality of code recognition. Furthermore, if you do not wish to use a QT connector but would prefer to connect it directly, you can do so using a mounting hole for a screw at the top left and some alternative pads. The edges of these pads are designed to be detached, should you need to further reduce the sensor’s dimensions.

Useful documents and links:

• CircuitPython sample code
• Tiny Code Reader Developer Guide
• Datasheet
• Adafruit “Reading QR Codes with the Tiny Code Reader” Tutorial

Adafruit name: Tiny Code Reader from Useful Sensors (ADA5744)