No reaction from DFrobot LCD keypad when button is pressed

Other Hardware Displays
1

Hello, I am having trouble with my LCD keypad, specifically that I have written the sketch and it is compiling with no errors, but the buttons are not displaying anything. I essentially just want to use the up and down to allow the user to be able to scroll on my menu page between 2 sensor options, temperature and heart rate. I have attached my code and even replaced the case of the down button to just print something just to individually test it but it is not printing anything. I would appreciate some help as to what my issue is. Thanks!

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

#define RIGHTbutton 0
#define UPbutton 1
#define DOWNbutton 2
#define LEFTbutton 3
#define SELECTbutton 4
#define NObutton 5

//buttons are connected by analog pin 0
double ButtonValues_adc = 0;
int ButtonValues_lcd = 0;



void setup() {
  // put your setup code here, to run once:
  lcd.begin(16, 2);
  lcd.setCursor(0, 0);
  lcd.print("Sensor Options: ");
  lcd.setCursor(0, 1);
  lcd.print("> Temperature ");
  //lcd.setCursor(0, 2);
  //lcd.print("> Heart Rate");
  //delay(500);
}
void loop() {
  // put your main code here, to run repeatedly:

  static int col = 0;
  static int row = 0;
  //lcd.setCursor(0, 1);
  ButtonValues_lcd = LCD_ReadButtons();

  switch (ButtonValues_lcd) {
    case DOWNbutton:
      {
        lcd.blink();
        lcd.setCursor(col, row);
        break;
      }
    case UPbutton:
      {
        lcd.blink();
        lcd.setCursor(col, 0);
      }
    case RIGHTbutton:
      {
        lcd.setCursor(col++, row);
        break;
      }
    case LEFTbutton:
      {
        lcd.setCursor(col--, row);
        break;
      }
  }
  //delay(500);
}


int LCD_ReadButtons() {  //function that determines which button is pressed
  ButtonValues_adc = analogRead(0);

  if (ButtonValues_adc > 1000) return NObutton;
  if (ButtonValues_adc < 850) return SELECTbutton;
  if (ButtonValues_adc < 650) return LEFTbutton;
  if (ButtonValues_adc < 450) return DOWNbutton;
  if (ButtonValues_adc < 250) return UPbutton;
  if (ButtonValues_adc < 50) return RIGHTbutton;
  return NObutton;
}
3

You might want to think about the order of these statements... example a value of < 50... is also < 850... the < 850 if statement will trigger first and exit the routine.

You probably want to do this regardless of the button pressed.

4

Thank you so much that was what the issue was!
I was also wondering about something similar to a low-power mode and how that would work? Digital pin 10 controls the backlight of the lcd and I tried making an if statement before my void loop ends with these conditions where im basically saying if a certain amount of time has passed and no button has been pressed, to turn the backlight off and the second that if the backlight is off and a button is pressed for it to turn on, but I am not getting it to work. Thanks!

if(millis()==10,000 && ButtonValues_adc == 1023){
digitalWrite(BACKlight, LOW);
  }

  if(ButtonValues_adc<1000 && digitalRead(BACKlight) == LOW){
    digitalWrite(BACKlight, HIGH);
  }
5

This probably doesn't do what you want. Firstly, you shouldn't have a comma (,) in the 10000.

Secondly, even if that syntax was correct, the statement will only be true for a single millisecond.

What you need to do is create another variable, say buttonPressed.

unsigned long buttonPressed = 0;

When any button is pressed you set buttonPressed to millis(), and also turn on the backlight;

Then in your main loop you can check...

if (millis() - buttonPressed > 10000)
  // Turn the backlight off.

So basically you are checking the amount of time that has passed since a button was pressed, if more than 10 seconds turn off the backlight.

6

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