Why my LCD does not work with this if statement?

Question

#include <LiquidCrystal.h>
LiquidCrystal lcd(1, 2, 4, 5, 6, 7); 
int greenLedPin = 12;
int blueLedPin = 11;
int redLedPin = 8;
int yellowLEdPin = 9;
int lightSensorPin = A0;
int analogValue = 0;
void setup() {
 // put your setup code here, to run once:
 lcd.begin(16, 2); 
 pinMode(greenLedPin, OUTPUT);
 pinMode(blueLedPin, OUTPUT);
 pinMode(redLedPin, OUTPUT);
 pinMode(yellowLEdPin, OUTPUT);
 Serial.begin(9600);
 while (! Serial);
}
void loop() {
 // put your main code here, to run repeatedly:
 Serial.println(analogRead(lightSensorPin));
 analogValue = analogRead(lightSensorPin);
 if (analogValue < 50) {
digitalWrite(redLedPin, HIGH);
 }
 else if (analogValue >= 50 && analogValue <= 99) {
 digitalWrite(yellowLEdPin, HIGH);
 }
 else if (analogValue >= 100 && analogValue <= 300) {
 digitalWrite(blueLedPin, HIGH);
 lcd.print("its bright");
 }
 else {
 digitalWrite(greenLedPin, HIGH);
 lcd.print("its bright");
 }
 delay(3000);
 digitalWrite(greenLedPin, LOW);
 digitalWrite(blueLedPin, LOW);
 digitalWrite(redLedPin, LOW);
 digitalWrite(yellowLEdPin, LOW);
 lcd.clear();
}

I'm very new to this so sorry if its a dumb mistake and I know my LCD is working right, since I have tested it so all the pins are good.

• per1234: On the Uno, pin 0 and 1 are used for Serial. You can't use pin 1 for Serial in addition to the LCD. What happens if you change the wiring to use a different pin and update the code accordingly?
• per1234: You're welcome. I'm very glad to hear that! I have written a formal answer so that this question can be considered answered by the Stack Exchange system. If you consider it the correct answer, you can "accept" it.

Answer 1

On the Uno, pin 0 and 1 are used for Serial. You can't use pin 1 for Serial in addition to the LCD. In general, it's best to avoid using pins 0 and 1.

You need to change the LCD wiring to use a different pin and update the code accordingly. For example, if you moved the LCD's RS pin connection from pin 1 on your Arduino to pin 13, you would update this line from:

LiquidCrystal lcd(1, 2, 4, 5, 6, 7);

to:

LiquidCrystal lcd(13, 2, 4, 5, 6, 7);

After that, your LCD should work correctly.