Added AM2302 sensor reading to one of the screens

include/am2302_sensor.h

@@ -0,0 +1,28 @@
+#ifndef AM2302_SENSOR_H
+#define AM2302_SENSOR_H
+
+#include <Arduino.h>
+
+struct Am2302Reading
+{
+  float temperatureC;
+  float humidityPercent;
+  bool valid;
+};
+
+class Am2302Sensor
+{
+public:
+  explicit Am2302Sensor(uint8_t pin);
+
+  void begin();
+  bool update(unsigned long now);
+  Am2302Reading reading() const;
+
+private:
+  uint8_t pin_;
+  unsigned long nextRead_;
+  Am2302Reading reading_;
+};
+
+#endif

include/carousel.h

@@ -15,6 +15,7 @@ public:
   Carousel(Screen *screens, size_t screenCount);
   void draw(U8G2 &u8g2);
   bool consumeDirty();
+  void requestRedraw();
   void nextScreen();
   void update(unsigned long now);
 
@@ -26,4 +27,4 @@ private:
   bool dirty_;
 };
 
-#endif
+#endif

include/screens.h

@@ -3,8 +3,11 @@
 
 #include <U8g2lib.h>
 
+#include "am2302_sensor.h"
+
 void drawScreen1(U8G2 &u8g2);
-void drawScreen2(U8G2 &u8g2);
+void setEnvironmentReading(Am2302Reading reading);
+void drawEnvironmentScreen(U8G2 &u8g2);
 void drawWeatherIconScreen(U8G2 &u8g2);
 
 #endif

src/am2302_sensor.cpp

@@ -0,0 +1,48 @@
+#include "am2302_sensor.h"
+
+#include <DHT.h>
+
+namespace
+{
+const unsigned long sensorReadInterval = 30000;
+
+DHT *dht = nullptr;
+}
+
+Am2302Sensor::Am2302Sensor(uint8_t pin)
+    : pin_(pin),
+      nextRead_(0),
+      reading_{0.0F, 0.0F, false} {}
+
+void Am2302Sensor::begin()
+{
+  static DHT sensor(pin_, DHT22);
+  dht = &sensor;
+  dht->begin();
+}
+
+bool Am2302Sensor::update(unsigned long now)
+{
+  if (now < nextRead_) {
+    return false;
+  }
+
+  nextRead_ = now + sensorReadInterval;
+  const float humidity = dht->readHumidity();
+  const float temperature = dht->readTemperature();
+
+  if (isnan(humidity) || isnan(temperature)) {
+    reading_.valid = false;
+    return true;
+  }
+
+  reading_.temperatureC = temperature;
+  reading_.humidityPercent = humidity;
+  reading_.valid = true;
+  return true;
+}
+
+Am2302Reading Am2302Sensor::reading() const
+{
+  return reading_;
+}

src/carousel.cpp

@@ -22,6 +22,11 @@ bool Carousel::consumeDirty()
   return d;
 }
 
+void Carousel::requestRedraw()
+{
+  dirty_ = true;
+}
+
 void Carousel::nextScreen()
 {
   currentIndex_ = (currentIndex_ + 1) % screenCount_;

src/main.cpp

@@ -2,23 +2,26 @@
 #include <U8g2lib.h>
 #include <Wire.h>
 
+#include "am2302_sensor.h"
 #include "carousel.h"
 #include "screens.h"
 
 U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R2, U8X8_PIN_NONE);
 
 int lastButtonNextState = LOW;
-uint8_t buttonNext = A3;
+uint8_t buttonNext = A4;
+Am2302Sensor am2302(A3);
 
 Screen screens[] = {
   { drawScreen1 },
-  { drawScreen2 },
+  { drawEnvironmentScreen },
   { drawWeatherIconScreen }
 };
 Carousel carousel(screens, sizeof(screens) / sizeof(screens[0]));
 
 void setup() {
   pinMode(buttonNext, INPUT);
+  am2302.begin();
 
   u8g2.begin();
   u8g2.clearBuffer();
@@ -29,6 +32,11 @@ void loop(){
   const unsigned long now = millis();
   carousel.update(now);
 
+  if (am2302.update(now)) {
+    setEnvironmentReading(am2302.reading());
+    carousel.requestRedraw();
+  }
+
   const int currentButtonState = digitalRead(buttonNext);
   if (lastButtonNextState == LOW && currentButtonState == HIGH) {
       carousel.nextScreen();

src/screens.cpp

@@ -2,6 +2,8 @@
 
 namespace
 {
+Am2302Reading environmentReading = {0.0F, 0.0F, false};
+
 void drawSun(U8G2 &u8g2, uint8_t x, uint8_t y)
 {
   u8g2.drawDisc(x, y, 11);
@@ -31,10 +33,29 @@ void drawScreen1(U8G2 &u8g2)
   u8g2.drawStr(0, 20, "Screen 1");
 }
 
-void drawScreen2(U8G2 &u8g2)
+void setEnvironmentReading(Am2302Reading reading)
 {
+  environmentReading = reading;
+}
+
+void drawEnvironmentScreen(U8G2 &u8g2)
+{
+  u8g2.setFont(u8g2_font_6x12_tr);
+  u8g2.drawStr(0, 12, "AM2302");
+
+  if (!environmentReading.valid) {
+    u8g2.setFont(u8g2_font_ncenB14_tr);
+    u8g2.drawStr(0, 40, "No data");
+    return;
+  }
+
   u8g2.setFont(u8g2_font_ncenB14_tr);
-  u8g2.drawStr(0, 40, "Screen 2");
+  u8g2.setCursor(0, 34);
+  u8g2.print(environmentReading.temperatureC, 1);
+  u8g2.print(" C");
+  u8g2.setCursor(0, 60);
+  u8g2.print(environmentReading.humidityPercent, 0);
+  u8g2.print(" %");
 }
 
 void drawWeatherIconScreen(U8G2 &u8g2)