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libraries/DHT20/examples/DHT20_lcd/DHT20_lcd.ino

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+//
+//    FILE: DHT20_lcd.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: Demo for DHT20 I2C humidity & temperature sensor
+//     URL: https://github.com/RobTillaart/DHT20
+//
+//  Always check datasheet - front view
+//
+//          +--------------+
+//  VDD ----| 1            |
+//  SDA ----| 2    DHT20   |
+//  GND ----| 3            |
+//  SCL ----| 4            |
+//          +--------------+
+
+
+#include "DHT20.h"
+
+DHT20 DHT;
+
+uint8_t count = 0;
+
+uint32_t stop, start;
+
+
+///////////////////////////////////////////////////////////////////////////
+
+#include <Wire.h>
+#include <LCD.h>
+#include <LiquidCrystal_I2C.h>
+
+#define BACKLIGHT_PIN   3
+#define En_pin          2
+#define Rw_pin          1
+#define Rs_pin          0
+#define D4_pin          4
+#define D5_pin          5
+#define D6_pin          6
+#define D7_pin          7
+
+#define  BL_OFF         0
+#define  BL_ON          1
+
+/*
+  #define BACKLIGHT_PIN  7
+  #define En_pin  4
+  #define Rw_pin  5
+  #define Rs_pin  6
+  #define D4_pin  0
+  #define D5_pin  1
+  #define D6_pin  2
+  #define D7_pin  3
+
+  #define LED_OFF 0
+  #define LED_ON  1
+*/
+
+int displayAddress = 0x27;
+
+//  LCD object is created as a placeholder as the actual address is determined in setupDisplay()
+//  constructor needs an I2C address. Better solution would be a function to set the address
+//  runtime in the class.
+LiquidCrystal_I2C  lcd(displayAddress);
+
+void setupDisplay()
+{
+  lcd = LiquidCrystal_I2C(displayAddress, En_pin, Rw_pin, Rs_pin, D4_pin, D5_pin, D6_pin, D7_pin);
+  lcd.begin(20, 4);
+  //  lcd.setBacklightPin(BACKLIGHT_PIN, NEGATIVE);
+  lcd.setBacklightPin(BACKLIGHT_PIN, POSITIVE);
+  lcd.setBacklight(BL_ON);
+}
+
+
+void display()
+{
+  lcd.clear();
+  lcd.setCursor(0, 0);
+  lcd.print("TEMP:");
+  lcd.setCursor(6, 0);
+  lcd.print(DHT.getTemperature());
+
+  lcd.setCursor(0, 1);
+  lcd.print("HUM:");
+  lcd.setCursor(6, 1);
+  lcd.print(DHT.getHumidity());
+
+  lcd.setCursor(0, 3);
+  lcd.print("TIME:");
+  lcd.setCursor(6, 3);
+  lcd.print(stop - start);
+}
+
+
+
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("DHT20 LIBRARY VERSION: ");
+  Serial.println(DHT20_LIB_VERSION);
+  Serial.println();
+
+  Wire.begin();
+  DHT.begin();    //  ESP32 default pins 21 22
+
+  setupDisplay();
+
+  delay(1000);
+}
+
+
+void loop()
+{
+  if (millis() - DHT.lastRead() >= 1000)
+  {
+    //  READ DATA
+    start = micros();
+    int status = DHT.read();
+    stop = micros();
+
+    display();
+
+    if ((count % 10) == 0)
+    {
+      count = 0;
+      Serial.println();
+      Serial.println("Type\tHumidity (%)\tTemp (°C)\tTime (µs)\tStatus");
+    }
+    count++;
+
+    Serial.print("DHT20 \t");
+    //  DISPLAY DATA, sensor has only one decimal.
+    Serial.print(DHT.getHumidity(), 1);
+    Serial.print("\t\t");
+    Serial.print(DHT.getTemperature(), 1);
+    Serial.print("\t\t");
+    Serial.print(stop - start);
+    Serial.print("\t\t");
+    switch (status)
+    {
+      case DHT20_OK:
+        Serial.print("OK");
+        break;
+      case DHT20_ERROR_CHECKSUM:
+        Serial.print("Checksum error");
+        break;
+      case DHT20_ERROR_CONNECT:
+        Serial.print("Connect error");
+        break;
+      case DHT20_MISSING_BYTES:
+        Serial.print("Missing bytes");
+        break;
+      case DHT20_ERROR_BYTES_ALL_ZERO:
+        Serial.print("All bytes read zero");
+        break;
+      case DHT20_ERROR_READ_TIMEOUT:
+        Serial.print("Read time out");
+        break;
+      case DHT20_ERROR_LASTREAD:
+        Serial.print("Error read too fast");
+        break;
+      default:
+        Serial.print("Unknown error");
+        break;
+    }
+    Serial.print("\n");
+  }
+}
+
+
+//  -- END OF FILE --