I have a project that i implemented in my work for me and my colleges, witsh consistes on an Arduino Nano with 4 DS18B20 connected to the pc to read several temperatures in serial monitor.
The project now needs to evolve to an equipment that does not need the computer by adding a 20x4 I2C Display.
That's where the problem starts, i found a sketch on the internet, but the display only turns on and off the backlight, and doesn't print anything on the display.
Can anyone help me to try and understand what is wrong.
Thank you.
/* YourDuino.com Example: Multiple DS18B20 Temperature Sensors
Displayed on 4x20 character LCD display
DS18B20 Pinout (Left to Right, pins down, flat side toward you)
- Left = Ground
- Center = Signal (Pin 10): (with 3.3K to 4.7K resistor to +5 or 3.3 )
- Right = +5 or +3.3 V
/*-----( Import needed libraries )-----*/
// Get 1-wire Library here: http://www.pjrc.com/teensy/td_libs_OneWire.html
#include <OneWire.h>
//Get DallasTemperature Library here: http://milesburton.com/Main_Page?title=Dallas_Temperature_Control_Library
#include <DallasTemperature.h>
// Wire (I2C) Library
#include <Wire.h>
// LCD Library
#include <LCD.h>
#include <LiquidCrystal_I2C.h> // F Malpartida's NewLiquidCrystal library
//Download: https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads
// Move original LiquidCrystal library elsewhere, copy this in it's place
/*-----( Declare Constants and Pin Numbers )-----*/
// Data wire is plugged into port 10 on the Arduino (can be changed)
#define ONE_WIRE_BUS 10 // NOTE: No ";" on #define
#define I2C_ADDR 0x27 // Define I2C Address for the PCF8574A on the LCD Backpack board
//---(Following are the PCF8574 pin assignments to LCD connections )----
// This are different than earlier/different I2C LCD displays
#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
/*-----( Declare objects )-----*/
// Setup a oneWire instance to communicate with any OneWire devices
// (not just Maxim/Dallas temperature ICs)
OneWire oneWire(ONE_WIRE_BUS);
// Pass address of our oneWire instance to Dallas Temperature.
DallasTemperature sensors(&oneWire);
// Start the LCD display library
LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);
/*-----( Declare Variables )-----*/
// Assign the addresses of your 1-Wire temp sensors.
// See the tutorial on how to obtain these addresses:
// http://arduino-info.wikispaces.com/Brick-Temperature-DS18B20#Read%20individual
// WP 1
DeviceAddress Probe01 = { 0x28, 0x9A, 0x80, 0x40, 0x04, 0x00, 0x00, 0xD5 }; // "4"
DeviceAddress Probe02 = { 0x28, 0xE1, 0xC7, 0x40, 0x04, 0x00, 0x00, 0x0D }; // "5"
DeviceAddress Probe03 = { 0x28, 0x9A, 0x80, 0x40, 0x04, 0x00, 0x00, 0xD5 }; // "4" Again for test
DeviceAddress Probe04 = { 0x28, 0x10, 0xA4, 0x57, 0x04, 0x00, 0x00, 0xA9 };
void setup() /****** SETUP: RUNS ONCE ******/
{
//------- Initialize the Temperature measurement library--------------
sensors.begin();
// set the resolution to 10 bit (Can be 9 to 12 bits .. lower is faster)
sensors.setResolution(Probe01, 10);
sensors.setResolution(Probe02, 10);
sensors.setResolution(Probe03, 10);
sensors.setResolution(Probe04, 10);
//---------------- Initialize the lcd ------------------
lcd.begin (20,4); // 20 characters, 4 lines
// Switch on the backlight
lcd.setBacklightPin(BACKLIGHT_PIN,NEGATIVE);
lcd.setBacklight(LED_ON);
}//--(end setup )---
void loop() /****** LOOP: RUNS CONSTANTLY ******/
{
sensors.requestTemperatures(); // Send the command to get temperatures
lcd.clear(); // Reset the display
lcd.home();
lcd.backlight(); //Backlight ON if under program control
// Print our characters on the LCD
// NOTE: Line number and character number start at 0 not 1
lcd.setCursor(0,0); //Start at character 0 on line 0
lcd.print("1: ");
displayTemperature(Probe01);
lcd.setCursor(0,1); //Start at character 0 on line 1
lcd.print("2: ");
displayTemperature(Probe02);
lcd.setCursor(0,2); //Start at character 0 on line 2
lcd.print("3: ");
displayTemperature(Probe03);
lcd.setCursor(0,3); //Start at character 0 on line 3
lcd.print("4: ");
displayTemperature(Probe04);
delay(2000);
}//--(end main loop )---
/*-----( Declare User-written Functions )-----*/
void displayTemperature(DeviceAddress deviceAddress)
{
float tempC = sensors.getTempC(deviceAddress);
if (tempC == -127.00) // Measurement failed or no device found
{
lcd.print("Temperature Error");
}
else
{
lcd.print("C=");
lcd.print(tempC);
lcd.print(" F=");
lcd.print(DallasTemperature::toFahrenheit(tempC)); // Convert to F
}
}// End printTemperature
//*********( THE END )***********
