Other Arduino Codes and Videos by Robojax
This displays temperature as bargraph on LCD1602-I2C or LCD2004-I2C
/*
* Display Temperature from HTU21D(F) on LCD as bargraph
* Written and Update by Ahmad Shamshiri on July 18, 2019
* for Robojax in Ajax, Ontario, Canada
Watch Video tutorial for this code :https://youtu.be/kpGvzNWLHuk
Must watch:
1- Introduction to HTU21DF
https://youtu.be/Q5y18rgTAhA
2- LCD1602-I2C video: https://youtu.be/q9YC_GVHy5A
* Original Sources:
* LCD library: https://github.com/fdebrabander/Arduino-LiquidCrystal-I2C-library
* Bargraph library from https://playground.arduino.cc/Code/LcdBarGraph/
*
*
* Robojax Arduino Course on Udemy where you get Schematic Diagram of this sketch
* and many other robotics related lectures and codes. Purchase the course here: http://bit.ly/rj-udemy
- (GND) to GND
+ (VDD) to 3.3V
(WARNING: do not connect + to 5V or the sensor will be damaged!)
*/
#include <Wire.h>
#include "Adafruit_HTU21DF.h"
Adafruit_HTU21DF htu = Adafruit_HTU21DF();
#define maxValue 160 // is the value in celsius or farenheit set in line above
// LCD settings
#include <LiquidCrystal_I2C.h>
byte lcdNumCols = 16; // -- number of columns in the LCD
byte lcdLine = 2; // -- number of line in the LCD
LiquidCrystal_I2C lcd(0x3f,lcdNumCols,lcdLine); //0x3f is address for I2C
// to get I2C address, run I2C Scanner.
//Link is provided (in same page as this code) at http://robojax.com/learn/arduino
// bargraph settings
#include <LcdBarGraphRobojax.h>
LcdBarGraphRobojax robojax(&lcd, 16, 0, 0); // -- creating 16 character long bargraph starting at char 0 of line 0 (see video)
void setup()
{
Serial.begin(9600);//initialize serial monitor
// -- initializing the LCD
lcd.begin();
lcd.clear();
lcd.print("Robojax");
// Initialize the sensor (it is important to get calibration values stored on the device).
if (htu.begin())
{
lcd.setCursor (0,1); //
lcd.print("HTU21DF Bargraph");
}else {
lcd.setCursor (0,1); //
lcd.print("missing HTU21DF");
while(1); // Pause forever.
}
// -- give use some time to read the text above
delay(2000);
lcd.clear();
}// setup
void loop()
{
// Robojax HTU21DF Bargraph main loop
robojax.clearLine(1);// clear line 1 to display fresh temperature
float T = getHTU('H');// get the temperature
float Tgraph=T;
if( Tgraph > maxValue){
Tgraph =0;
}
robojax.drawValue( Tgraph, maxValue);// draw the bargraph
// Print out the measurement:
Serial.print("temperature: ");
Serial.print(T,2);
lcd.setCursor (0,1); //
if(T< maxValue){
lcd.print("Temp.:");
//lcd.print("Humi.:");
}else{
lcd.print("Max.:");
}
lcd.setCursor (7,1); //
lcd.print(T); // print
lcd.print((char)223);// prints degree symbol
//lcd.print("%");// prints degree symbol
lcd.print("C");//
delay(500);
}
/*
* @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')
{
if(rel_hum<0){rel_hum =0;}//prevents it from negative value
value = rel_hum;//return relative humidity
}else{
value = temp;// return Celsius
}
return value;
}//
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