QR code display the CO2 values over last 24h

Press the button for 5+ seconds to show a QR code containing each the co2 values of 1h. Up to 24 QR codes will be stored. Measurements are only stored  and displayed in battery mode.

OpenCO2_Sensor.ino

@@ -65,11 +65,11 @@ Adafruit_DotStar strip(1, 40, 39, DOTSTAR_BRG); // numLEDs, DATAPIN, CLOCKPIN
 SensirionI2CScd4x scd4x;
 
 RTC_DATA_ATTR bool initDone = false;
-RTC_DATA_ATTR extern bool BatteryMode = false;
-RTC_DATA_ATTR extern bool comingFromDeepSleep = false;
+RTC_DATA_ATTR bool BatteryMode = false;
+RTC_DATA_ATTR bool comingFromDeepSleep = false;
 RTC_DATA_ATTR int ledbrightness = 5;
 RTC_DATA_ATTR bool LEDalwaysOn = false;
-RTC_DATA_ATTR extern int HWSubRev = 1; //default only
+RTC_DATA_ATTR int HWSubRev = 1; //default only
 RTC_DATA_ATTR float maxBatteryVoltage;
 
 /* TEST_MODE */
@@ -374,6 +374,52 @@ void rainbowMode() {
   }
 }
 
+RTC_DATA_ATTR uint8_t hour = 0;
+RTC_DATA_ATTR uint8_t halfminute = 0;
+RTC_DATA_ATTR uint16_t measurements[24][120];
+void saveMeasurement(uint16_t co2){
+  if (halfminute == 120) {
+    halfminute=0;
+    hour++;
+  }
+  if (hour == 24) {
+    for (int i=0; i<23; ++i) memcpy(measurements[i], measurements[i + 1], sizeof(uint16_t) * 120);
+    hour = 23;
+  }
+
+  measurements[hour][halfminute] = co2;
+  halfminute++;
+}
+
+int qrcodeNumber = 0;
+void fiveSecPressed() {
+  //rainbowMode();
+
+  //DEMO DATA:
+  /*hour = 2;
+  for (int i=0; i<120; i++) {
+    measurements[0][i] = 400+i;
+    measurements[1][i] = 520+i;
+    measurements[2][i] = 1000+i;
+  }
+  halfminute = 120;*/
+
+  qrcodeNumber = hour; // start at current hour
+  extern int refreshes;
+  refreshes = 1; // force full update
+  for (int i=0; i<200; i++) {
+    if (digitalRead(GPIO_NUM_0) == 0) {  //goto next qr code
+      displayQRcode(measurements);
+      goto_light_sleep(500);
+      if (qrcodeNumber == hour) qrcodeNumber = 0;
+      else qrcodeNumber++;
+      i = 0; //display qrcode again for 20 sec
+    }
+    delay(100);
+  }
+  refreshes = 1; // force full update
+}
+
 void setup() {
   pinMode(DISPLAY_POWER, OUTPUT);
   pinMode(LED_POWER, OUTPUT);
@@ -402,7 +448,10 @@ void setup() {
     pinMode(GPIO_NUM_0, INPUT_PULLUP);
     int secPressed = 0;
     while (digitalRead(GPIO_NUM_0) == 0) {
-      if (secPressed == 4) rainbowMode();
+      if (secPressed == 4) {
+        fiveSecPressed();
+        return;
+      }
       secPressed++;
       delay(1000);
     }
@@ -489,6 +538,7 @@ void loop() {
     errorToString(error, errorMessage, 256);
     displayWriteError(errorMessage);
   } else {
+    if (BatteryMode) saveMeasurement(new_co2);
     /* dont update in Battery mode, unless CO2 has changed by 3% or temperature by 0.5°C */
     if (!TEST_MODE && BatteryMode && comingFromDeepSleep) {
       if ((abs(new_co2 - co2) < (0.03*co2)) && (fabs(new_temperature - temperature) < 0.5)) {
@@ -572,7 +622,7 @@ void loop() {
       scd4x.setTemperatureOffset(0.8);
       scd4x.startLowPowerPeriodicMeasurement();
     }
-    goto_deep_sleep(29000);
+    goto_deep_sleep(29500);
   }
 
   goto_light_sleep(4000);

epd_abstraction.h

@@ -14,5 +14,6 @@ void displayWriteTestResults(float voltage, uint16_t sensorStatus, uint16_t seri
 void displayBattery(uint8_t percentage);
 void updateDisplay();
 void displayRainbow();
+void displayQRcode(uint16_t measurements[24][120]);
 
 #endif /* EPD_ABSTRACTION_H */

epd_abstraction.ino

@@ -19,6 +19,9 @@
 
 RTC_DATA_ATTR int refreshes = 1;
 RTC_DATA_ATTR UBYTE *BlackImage;
+extern bool BatteryMode;
+extern bool comingFromDeepSleep;
+extern int HWSubRev;
 
 sFONT big=bahn_big; //gotham_big nothing_big bahn_big
 sFONT mid=bahn_mid; //gotham_mid nothing_mid bahn_mid
@@ -196,6 +199,63 @@ void displayWriteMeasuerments(uint16_t co2, float temperature, float humidity) {
 #endif
 }
 
+#include "qrcode.h"
+#define ESP_QRCODE_CONFIG() (esp_qrcode_config_t) { \
+    .display_func = draw_qr_code, \
+    .max_qrcode_version = 26, \
+    .qrcode_ecc_level = ESP_QRCODE_ECC_LOW, \
+}
+
+void draw_qr_code(const uint8_t * qrcode) {
+  int qrcodeSize = esp_qrcode_get_size(qrcode);
+  int scaleFactor = 1;
+
+  if (qrcodeSize < 24)      scaleFactor = 7;
+  else if (qrcodeSize < 28) scaleFactor = 6;
+  else if (qrcodeSize < 34) scaleFactor = 5;
+  else if (qrcodeSize < 42) scaleFactor = 4;
+  else if (qrcodeSize < 56) scaleFactor = 3;
+  else if (qrcodeSize < 84) scaleFactor = 2;
+
+  int Start = (200 - (qrcodeSize *scaleFactor)) / 2;
+  Paint_Clear(WHITE);
+  for (int y=0; y < qrcodeSize; y++) {
+    for (int x=0; x < qrcodeSize; x++) {
+      if (esp_qrcode_get_module(qrcode, x, y)) {
+        if (scaleFactor > 1) Paint_DrawRectangle(Start + x * scaleFactor,
+                                                 Start + y * scaleFactor,
+                                                 Start + x * scaleFactor + scaleFactor, 
+                                                 Start + y * scaleFactor + scaleFactor,
+                                                 BLACK, DOT_PIXEL_1X1, DRAW_FILL_FULL);
+        else Paint_SetPixel(x + (200-qrcodeSize)/2, y + (200-qrcodeSize)/2, BLACK);
+      }
+    }
+  }
+
+  if (qrcodeNumber+1 >= 10) Paint_DrawNum(200-5*11, 200-16, qrcodeNumber+1, &Font16, BLACK, WHITE);
+  else Paint_DrawNum(200-4*11, 200-16, qrcodeNumber+1, &Font16, BLACK, WHITE);
+  Paint_DrawString_EN(200-3*11, 200-16, "/", &Font16, WHITE, BLACK);
+  Paint_DrawNum(200-2*11, 200-16, hour+1, &Font16, BLACK, WHITE);
+  updateDisplay();
+}
+
+void displayQRcode(uint16_t measurements[24][120]) {
+  char buffer[5*120+1];
+  int numEnties = halfminute;
+  if (hour > qrcodeNumber) numEnties = 120; // display all values included in previous hours
+
+  for (int i=0; i<numEnties; i++) {
+    char tempStr[6];
+    snprintf(tempStr, sizeof(tempStr), "%d", measurements[qrcodeNumber][i]);
+
+    if (i == 0) snprintf(buffer, sizeof(buffer), "%s", tempStr);
+    else snprintf(buffer + strlen(buffer), sizeof(buffer) - strlen(buffer), " %s", tempStr);
+  }
+
+  esp_qrcode_config_t cfg = ESP_QRCODE_CONFIG();
+  esp_qrcode_generate(&cfg, buffer);
+}
+
 void displayWriteError(char errorMessage[256]){
   Paint_DrawString_EN(5, 40, errorMessage, &Font20, WHITE, BLACK);
 }