Newbie here trying to print from DHT sensor to I2C, 20x4 display. I am combining two library sketches DHT tester and liquid crystal I2C. I know things have to be in the correct order but I am having difficulty getting that part right. I have removed much of the code to pare it down to just temp *F and humidity%. I have tried to make the line less than 20 characters and have also tried to make the display two separate lines thinking I may have issues because I sent too much code to the display. I get no response on the LCD so far no matter which order I place things in the code. I currently can still get data on the serial monitor from the DHT sensor. Earlier, I moved things around and lost that ability, but have never gotten anything to display on the LCD. I have no significant experience with an LCD either. I can currently still manually input data to the LCD by typing into the serial monitor.
I can make the serial display sketch work as designed by manually inputting data into the serial monitor, but I want to take it a step further and have it display data as it becomes available on the serial bus. Any advice would be appreciated.
Mod edit: code tags
I can make the serial display sketch work as designed by manually inputting data into the serial monitor, but I want to take it a step further and have it display data as it becomes available on the serial bus. Any advice would be appreciated.
C:
// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain
#include "DHT.h"
#define DHTPIN 2 // what digital pin we're connected to
// Uncomment whatever type you're using!
#define DHTTYPE DHT11 // DHT 11
//#define DHTTYPE DHT22 // DHT 22 (AM2302), AM2321
//#define DHTTYPE DHT21 // DHT 21 (AM2301)
// Connect pin 1 (on the left) of the sensor to +5V
// NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1
// to 3.3V instead of 5V!
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor
// Initialize DHT sensor.
// Note that older versions of this library took an optional third parameter to
// tweak the timings for faster processors. This parameter is no longer needed
// as the current DHT reading algorithm adjusts itself to work on faster procs.
DHT dht(DHTPIN, DHTTYPE);
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,20,4); // set the LCD address to 0x27 for a 20 chars and 4 line display
void setup() {
Serial.begin(9600);
Serial.println("DHT");
dht.begin();
lcd.init(); // initialize the lcd
lcd.backlight();
}
void loop() {
delay(2000);
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h = dht.readHumidity();
// Read temperature as Celsius (the default)
//float t = dht.readTemperature();
// Read temperature as Fahrenheit (isFahrenheit = true)
float f = dht.readTemperature(true);
// Check if any reads failed and exit early (to try again).
if (isnan(h) || isnan(f)) {
Serial.println("Failed to read from DHT sensor!");
return;
}
Serial.print("H: ");
Serial.print(h);
Serial.print(" %\t");
Serial.print("T: ");
Serial.print(f);
Serial.println(" *F\t");
// when characters arrive over the serial port...
if (Serial.available()) {
// wait a bit for the entire message to arrive
delay(100);
// clear the screen
lcd.clear();
// read all the available characters
while (Serial.available() > 0) {
// display each character to the LCD
lcd.write(Serial.read());
// Wait a few seconds between measurements.
}
}
}
Last edited by a moderator: