Backlight on/off

system · October 10, 2014, 6:34am

Hello, first at all sorry for my bad english.
I built a weather station with the arduino. It has two DTH (IN/OUT) sensors, pressure sensor, RTC clock, SD card data logging and photoresistor. Everything works perfectly. But there is one problem. I have a button which I want to turn on the backlight of the display. For some reason code found here: http://blog.rastating.com/toggling-the-backlight-of-hd44780-lcds-with-an-arduino-uno/ does not work in my program (display backlight and display itself doesnt turn on when button pressed. But thic code works properly when loaded separately. What could be the reason? The following program code is my code for weather station, probably has many flaws but it works, at the moment I'm interested in the inclusion of the backlight button. Im sure that hardware connections are correct. Thanks for any help.

/Libs
#include <LiquidCrystal.h> //LCD
#include <DHT.h> //DHT
#include <Wire.h> //1-Wire
#include <Adafruit_Sensor.h> //Sensors
#include <Adafruit_BMP085_U.h> //BMP180
#include <RTClib.h> //RTC
#include <SPI.h> //SPI
#include <SD.h> //SD card

#define DHT1PIN 8 //DHT IN pin
#define DHT2PIN 9 //DHT OUT pin

#define DHT1TYPE DHT11 //DHT IN type
#define DHT2TYPE DHT22 //DHT OUT type

#define LCD_LIGHT_PIN A2 //This is backlight pin

const int buttonPin = A1;  //Button pin  
int buttonState = 0;

DHT dht1(DHT1PIN, DHT1TYPE);
DHT dht2(DHT2PIN, DHT2TYPE); 

//Icons
byte t[8] = 
{
  0b00100,
  0b01010,
  0b01010,
  0b01110,
  0b01110,
  0b11111,
  0b11111,
  0b01110
};

byte w[8] = 
{
  0b00100,
  0b00100,
  0b01010,
  0b01010,
  0b10001,
  0b10001,
  0b10001,
  0b01110
};

byte sto[8] = {
	0b00110,
	0b01001,
	0b01001,
	0b00110,
	0b00000,
	0b00000,
	0b00000,
	0b00000
};

byte mc[8] = {
	0b00000,
	0b00111,
	0b01001,
	0b10001,
	0b10001,
	0b10001,
	0b10001,
	0b11111
};

Adafruit_BMP085_Unified bmp = Adafruit_BMP085_Unified(10085);
RTC_DS1307 rtc;
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //Piny wy?wietlacza
const int chipSelect = 53; //Pin CS karty SD 
File logfile;



void setup() {
  lcd.begin(20, 4);

//Turn off display
     lcd.noDisplay();

  // Set the button pin as an input.
  pinMode(buttonPin, INPUT);

   // Set the LCD display backlight pin as an output.
  pinMode(LCD_LIGHT_PIN, OUTPUT);

  // Turn off the LCD backlight.
  digitalWrite(LCD_LIGHT_PIN, LOW);

  dht1.begin();
  dht2.begin();
  bmp.begin();
  //rtc.adjust(DateTime(__DATE__, __TIME__));
 Serial.begin(9600);

 
  
 
  
  lcd.createChar(0, t);
  lcd.createChar(3, sto);
  lcd.createChar(5, w);
  lcd.createChar(7, mc);
  
   // initialize the SD card
  Serial.print("Initializing SD card...");
  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
  pinMode(10, OUTPUT);
  
  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    error("Card failed, or not present");
  }
  Serial.println("card initialized.");
    lcd.setCursor(19, 0);
    lcd.write(byte(7));

  // create a new file
  char filename[] = "LOGGER00.CSV";
  for (uint8_t i = 0; i < 100; i++) {
    filename[6] = i/10 + '0';
    filename[7] = i%10 + '0';
    if (! SD.exists(filename)) {
      // only open a new file if it doesn't exist
      logfile = SD.open(filename, FILE_WRITE); 
      break;  // leave the loop!
    }
  }
  
  if (! logfile) {
    error("couldnt create file");
  }
  
  Serial.print("Logging to: ");
  Serial.println(filename);

}



//Wysy?anie danych do portu szeregowego
void serialread(){
  delay(2000);
  sensors_event_t event;
  bmp.getEvent(&event);
  Serial.print("Cisnienie: ");
  Serial.print(event.pressure);
  Serial.print(" hPa\n");
  float temperature;
  bmp.getTemperature(&temperature);
  Serial.print("Temperatura: ");
  Serial.print(temperature);
  Serial.print("C\n");
  float seaLevelPressure = SENSORS_PRESSURE_SEALEVELHPA;
  Serial.print("Wysokosc: "); 
  Serial.print(bmp.pressureToAltitude(seaLevelPressure, event.pressure)); 
  Serial.print(" m\n");
  
  float h1 = dht1.readHumidity();
  Serial.print("Wilgotnosc IN: ");
  Serial.print(h1);
  Serial.print("%\n");
  
  float t1 = dht1.readTemperature();
  Serial.print("Temperatura IN: ");
  Serial.print(t1);
  Serial.print("C\n");
  
  float h2 = dht2.readHumidity();
  Serial.print("Wilgotnosc OUT: ");
  Serial.print(h2);
  Serial.print("%\n");
  
  float t2 = dht2.readTemperature();
  Serial.print("Temperatura OUT: ");
  Serial.print(t2);
  Serial.print("C\n");
  
  Serial.print("Natezenie swiatla");
  Serial.print(analogRead(A0));
  Serial.println();
}

void error(char *str)
{
  Serial.print("error: ");
  while(1);
}

//Wilgotno?? i temperatura IN
void htIN(){ 
  delay(2000);
  int h1 = dht1.readHumidity();
  float t1 = dht1.readTemperature();
  float temperature;
  bmp.getTemperature(&temperature);
  lcd.setCursor(0, 1);
  lcd.print("I: "); 
  lcd.write(byte(5));
  lcd.print(h1);
  lcd.print("% ");
  lcd.write(byte(0));
  lcd.print((t1+temperature)/2);
  lcd.write(byte(3));
  lcd.print("C"); 
}

//Wilgotno?? i temperatura OUT
void htOUT(){
  delay(2000);
  int h2 = dht2.readHumidity();
  float t2 = dht2.readTemperature();
  lcd.setCursor(0, 2);
  lcd.print("O: "); 
  lcd.write(byte(5));
  lcd.print(h2);
  lcd.print("% ");
  lcd.write(byte(0));
  lcd.print(t2);
  lcd.write(byte(3));
  lcd.print("C");
}

//Ci?nienie i temperatura IN
void ptIN(){
  sensors_event_t event;
  bmp.getEvent(&event);
  //float temperature; //Nie wyswietlamy temperatury
  lcd.setCursor(0, 3);
  lcd.print("O: ");
  lcd.print(event.pressure);
  lcd.print("hPa ");  
  //bmp.getTemperature(&temperature); //Nie wyswietlamy temperatury
  //lcd.print(temperature); //Nie wyswietlamy temperatury
  //lcd.print("C"); //Nie wyswietlamy temperatury
}  

//Czas i data
void cl(){
   DateTime now = rtc.now();
   lcd.setCursor(2, 0);
   if(now.hour() < 10) (lcd.print(0));
   lcd.print(now.hour(), DEC);
   lcd.print(':');
   if(now.minute() < 10) (lcd.print(0));
   lcd.print(now.minute(), DEC);
   //lcd.print(':');
   //lcd.print(now.second(), DEC);
   lcd.print(" ");
   if(now.day() < 10) (lcd.print(0));
   lcd.print(now.day(), DEC);
   lcd.print('/');
   if(now.month() < 10) (lcd.print(0));
   lcd.print(now.month(), DEC);
   lcd.print('/');
   lcd.print(now.year(), DEC);
}

void light(){
   int lightLevel = analogRead(A0);
   lcd.setCursor(14, 3);
   lcd.print(lightLevel);
   lcd.print("lux"); 
}

//Rejestrowanie na karcie SD (hh:mm:ss, dd/mm/rrrr, w1, t1, w2, t2, light, pressure, t3)
void sd(){
  delay(60000);
  DateTime now = rtc.now();
  if(now.hour() < 10) (logfile.print(0));
  logfile.print(now.hour(), DEC);
  logfile.print(':');
  if(now.minute() < 10) (logfile.print(0));
  logfile.print(now.minute(), DEC);
  logfile.print(':');
  if(now.second() < 10) (logfile.print(0));
  logfile.print(now.second(), DEC);
  logfile.print(", ");
  if(now.day() < 10) (logfile.print(0));
  logfile.print(now.day(), DEC);
  logfile.print('/');
  if(now.month() < 10) (logfile.print(0));
  logfile.print(now.month(), DEC);
  logfile.print('/');
  logfile.print(now.year(), DEC);
  logfile.print(", ");
  sensors_event_t event;
  bmp.getEvent(&event);
  logfile.print(dht1.readHumidity());
  logfile.print(", ");
  logfile.print(dht1.readTemperature());
  logfile.print(", ");
  logfile.print(dht2.readHumidity());
  logfile.print(", ");
  logfile.print(dht2.readTemperature());
  logfile.print(", ");
  logfile.print(analogRead(A0));
  logfile.print(", ");
  logfile.print(event.pressure);
  logfile.print(", ");
  float temperature;
  bmp.getTemperature(&temperature);
  logfile.print(temperature);
  logfile.println();
  logfile.flush();
}


void loop(){
 
   buttonState = digitalRead(buttonPin);
  if (buttonState == HIGH)
  {
   
    // Turn the backlight on.
    digitalWrite(LCD_LIGHT_PIN, HIGH);

    // Display the text on the LCD.
    lcd.display();

    // Wait for 10 seconds and then turn off the display and backlight.
    delay(10000);
    lcd.noDisplay();
    digitalWrite(LCD_LIGHT_PIN, LOW);
  }
  htIN();
  htOUT();
  ptIN();
  cl();
  light();
  serialread();
  sd();
}

johnwasser · October 10, 2014, 2:00pm

Because of all the delay() calls in your code it will only check the button every 66 seconds! You will have to get rid of those delays. Use the BlinkWithoutDelay example as an example of how to use the millis() timer to schedule function calls.

void loop() {
  buttonState = digitalRead(buttonPin);
  if (buttonState == HIGH) {
  }
  htIN();  // delays 2 seonds
  htOUT();  // delays 2 seconds
  ptIN();
  cl();
  light();
  serialread();  // delays 2 seconds
  sd();  // delays 60 seconds
}

system · October 10, 2014, 2:06pm

#define LCD_LIGHT_PIN A2 //This is backlight pin

const int buttonPin = A1;  //Button pin  
int buttonState = 0;

Why are you using two different formats to define pin numbers?

How large a value is the pin number? How large a value is the pin state? Do you really need to use ints to store byte sized values?

Im sure that hardware connections are correct.

So confident that I'm not going to tell you how the switch is wired!

void serialread(){

That's a pretty stupid name for a function that does not read any serial data!

   buttonState = digitalRead(buttonPin);
  if (buttonState == HIGH)
  {
   
    // Turn the backlight on.
    digitalWrite(LCD_LIGHT_PIN, HIGH);

    // Display the text on the LCD.
    lcd.display();

    // Wait for 10 seconds and then turn off the display and backlight.
    delay(10000);
    lcd.noDisplay();
    digitalWrite(LCD_LIGHT_PIN, LOW);
  }

You don't even KNOW that the pin is being read correctly.

system · October 10, 2014, 5:50pm

johnwasser:
Because of all the delay() calls in your code it will only check the button every 66 seconds! You will have to get rid of those delays. Use the BlinkWithoutDelay example as an example of how to use the millis() timer to schedule function calls.

Thanks, I thought that the delay() may be causing the problem but I'm still not sure how to fix it. I tried the example of milis() timer and it also was working correct when it was loaded separately, but when I add the code into the weather station code it does not work like with the delay ().

system · October 10, 2014, 5:57pm

PaulS:

#define LCD_LIGHT_PIN A2 //This is backlight pin

const int buttonPin = A1; //Button pin
int buttonState = 0;



Why are you using two different formats to define pin numbers?
**It was in example code in this way.**
How large a value is the pin number? How large a value is the pin state? Do you really need to use ints to store byte sized values?



> Im sure that hardware connections are correct.


So confident that I'm not going to tell you how the switch is wired!
**It works as separate code so hardware connection must be correct.**
`void serialread(){`
That's a pretty stupid name for a function that does not read any serial data!
**Sorry, I mean that let to read data to PC, should be serialsend.**

buttonState = digitalRead(buttonPin);
if (buttonState == HIGH)
{

// Turn the backlight on.
digitalWrite(LCD_LIGHT_PIN, HIGH);

// Display the text on the LCD.
lcd.display();

// Wait for 10 seconds and then turn off the display and backlight.
delay(10000);
lcd.noDisplay();
digitalWrite(LCD_LIGHT_PIN, LOW);
}



You don't even KNOW that the pin is being read correctly.

johnwasser · October 10, 2014, 8:34pm

elektrownik:
Thanks, I thought that the delay() may be causing the problem but I'm still not sure how to fix it. I tried the example of milis() timer and it also was working correct when it was loaded separately, but when I add the code into the weather station code it does not work like with the delay ().

You have to decide what parts you want executed every time through loop() (like checking the button) and what parts you want run less often. For the parts you want run less often you have to decide how often they run. Right now everything is done every 66 seconds if the button is not pressed and every 76 seconds as long as the button is pressed.

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