OLED How to display QR code

#1

Can I display QR code in the OLED dysplay?

For example this library:

#2

@jasonXu friend do you think is possible generate QR code with devEUI and show over OLED ?

#3

Yes, I think this can be achieved.

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But you need the High pixel OLED screen to display the QR code.

#4

The included screen will not meet the requirements to show QR code ?

#5

yes, the AB02’s screen is Too narrow.

1 Like
#6

QR code generation is possible on Heltec ESP32 kit that comes with OLED. However due to the display size limitation, the maximum number of characters that it can convert to a QR code is also much less. The tests I did so far could only code less than 15 characters. Here is the code that works. Courtesy: https://eugeniopace.org/qrcode/arduino/eink/2019/07/01/qrcode-on-arduino.html

Install this library: https://github.com/ricmoo/QRCode

#include "qrcode.h"
#include "heltec.h"

void setup() {
    Serial.begin(115200);
    Heltec.begin(true, false, true);
    Heltec.display->clear();

    // Create the QR code
    QRCode qrcode;
    const int qrcodeVersion = 3; 
    const int pixelsPerSquare = 2; 
    const int ecc_low = 0;
    
    uint8_t qrcodeData[qrcode_getBufferSize(qrcodeVersion)];
    qrcode_initText(&qrcode, qrcodeData, qrcodeVersion, ecc_low, "HELLO WORLD");

    for (uint8_t y = 0; y < qrcode.size; y++) {
        for (uint8_t x = 0; x < qrcode.size; x++) {
          //If pixel is on, we draw a ps x ps black square
          if (qrcode_getModule(&qrcode, x, y)) {
            for(int xi = x*pixelsPerSquare + 2; xi < x*pixelsPerSquare + pixelsPerSquare + 2; xi++){
              for(int yi= y*pixelsPerSquare + 2; yi < y*pixelsPerSquare + pixelsPerSquare + 2; yi++){
                Heltec.display->setPixel(xi, yi);
              }
            }
          } 
        }
    }
    Heltec.display->display();
}

void loop() {
}