M5StickC 環境光センサ Hat。ロームのBH1750FVを利用 。 https://twitter.com/ksasao/status/1488550499549065218

luminometer.ino

#include <M5GFX.h>
#include <M5StickCPlus.h>
#include <M5_BH1750FVI.h>

M5GFX display;

M5_BH1750FVI sensor;
uint16_t lux;

void setup() {
  M5.begin();
  display.init();
  display.setRotation(1);
  
  sensor.begin();

  //CONTINUOUSLY_H_RESOLUTION_MODE
  //CONTINUOUSLY_H_RESOLUTION_MODE2
  //CONTINUOUSLY_L_RESOLUTION_MODE
  //ONE_TIME_H_RESOLUTION_MODE
  //ONE_TIME_H_RESOLUTION_MODE2
  //ONE_TIME_L_RESOLUTION_MODE
  sensor.setMode(CONTINUOUSLY_H_RESOLUTION_MODE);
}

char txt[64];

void drawText(int lux){
  sprintf(txt,"   %5d", lux);
  display.setTextColor(TFT_WHITE, TFT_BLACK);
  display.setTextWrap(false);
  display.setTextDatum(textdatum_t::top_right);
  display.setTextSize(0.75,1);
  display.setFont(&fonts::Font8);
  display.drawString(txt, 223,10);
  display.setFont(&fonts::lgfxJapanGothic_40);
  display.drawString("lux", 220,85);
}

void loop() {
  lux = sensor.getLUX();
  Serial.println(lux);
  if (!display.displayBusy())
  {
    display.startWrite();
    drawText(lux);
    display.endWrite();
  }
  delay(100);
}