Other Arduino Codes and Videos by Robojax
This code displays the temperature as Celsius, Fahrenheit or Kelvin or humidity on the LCD1602-I2C or LCD2004 displays.
/*
* Display Temperature from HTU21DF on LCD1602-I2C or LCD2004
* Updated by Ahmad Shamshiri on July 13, 2019
* in Ajax, Ontario, Canada
* Watch video instruction for this sketch: https://youtu.be/IF46cqvKijU
**************************************************
*
This is an example for the HTU21D-F Humidity & Temp Sensor
Designed specifically to work with the HTU21D-F sensor from Adafruit
----> https://www.adafruit.com/products/1899
These displays use I2C to communicate, 2 pins are required to
interface
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You can get the wiring diagram from my Arduino Course at Udemy.com
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* Code is available at http://robojax.com/learn/arduino
* This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.*
* This code has been download from Robojax.com
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <Wire.h>
#include "Adafruit_HTU21DF.h"
// Connect Vin to 3-5VDC
// Connect GND to ground
// Connect SCL to I2C clock pin (A5 on UNO)
// Connect SDA to I2C data pin (A4 on UNO)
Adafruit_HTU21DF htu = Adafruit_HTU21DF();
// start of settings for LCD1602 with I2C
#include <LiquidCrystal_I2C.h>
// Set the LCD address to 0x27 for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x3F, 16, 2);
// end of settings for LCD1602 with I2C
void setup() {
lcd.begin();
lcd.backlight();
if (!htu.begin()) {
lcd.print("Robojax HTUD1DF");
lcd.setCursor(0,1);
lcd.print("sensor missing");
while (1);
}else{
// initialize the LCD
lcd.print("Robojax HTUD1DF");
lcd.setCursor(0,1);
lcd.print("Demo");
}
delay(2000);
}
void loop() {
lcd.clear();// clear previous values from screen
lcdDisplay(
// to print Celsius:
0, // character 0
0, // line 0
"Celsius: ",
// to print Celsius
10, // character 10
0, // line 0
getHTU('C'),
'd'
);
lcdDisplay(
// to print Fahrenheit:
0, // character 0
1, // line 1
"Fahrenh.: ",
// to print Fahrenheit
10, // character 9
1, // line 0
getHTU('F'),
'd'
);
delay(5000);
lcdDisplay(
// to print Kelvin:
0, // character 0
0, // line 0
"Kelvin: ",
// to print Celsius
9, // character 10
0, // line 0
getHTU('K'),
'k'
);
lcdDisplay(
// to print humidity text
0, // character 0
1, // line 1
"Humidity.: ",
// to print humidity
10, // character 9
1, // line 1
getHTU('H'),
'%'
);
delay(5000);
}
/*
* @brief returns temperature or relative humidity
* @param "type" is character
* C = Celsius
* K = Keliven
* F = Fahrenheit
* H = Humidity
* @return returns one of the values above
* Usage: to get Fahrenheit type: getHTU('F')
* to print it on serial monitor Serial.println(getHTU('F'));
* Written by Ahmad Shamshiri on July 13, 2019
* in Ajax, Ontario, Canada
* www.Robojax.com
*/
float getHTU(char type)
{
float value;
float temp = htu.readTemperature();
float rel_hum = htu.readHumidity();
if(type =='F')
{
value = temp *9/5 + 32;//convert to Fahrenheit
}else if(type =='K')
{
value = temp + 273.15;//convert to Kelvin
}else if(type =='H')
{
value = rel_hum;//return relative humidity
}else{
value = temp;// return Celsius
}
return value;
}//
/*
* lcdDisplay(int tc, int tr, String title, int vc, int vr, float value)
* displays value and title on LCD1602
* How to use:
* If you wan to diaplay: "Voltage: 13.56mV" starting from first character
* on second row.
* use:
* lcdDisplay(0, 1, "Voltage: ", 13.56,'d')
*
* 'd' is degree symbol
* tc is character number (0)
* tr is row in the lcd (1)
* title is the text (Voltage:)
* vc value for character
* vr value for row or line
* value is the value (13.56)
*/
void lcdDisplay(int tc, int tr, String title, int vc, int vr, float value,char symbol)
{
// Robojax.com LCD1602 for HTU21D Demo
lcd.setCursor (tc,tr); //
lcd.print(title);
lcd.setCursor (vc,vr); //
lcd.print(value);
if(symbol == 'd')
{
lcd.print((char)223);
}else if(symbol =='%')
{
lcd.print("%");
}else if(symbol =='k')
{
lcd.print("K");
}
// Robojax.com LCD1602 for HTU21D Demo
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