电位器过低时 LCD 会自行清零

Question

I'm making a project that requires an lcd, and the project was working fine on my breadboard for testing. I moved it to my final product, but now my lcd stops displaying text after a few minutes, or when the potetiometer value is too low. One thing that really gets my attention is that if the potentiometer is fully high, the lcd doesn't clear by itself. When I lower it, it happens again. I have a refresh rate in this project as well for about every 250 milliseconds. Here is the code for my project along with it's schematic.

schematic -

code -

#include <LiquidCrystal.h>
#include <RTClib.h>
#include <Wire.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 6);
int lcdPreviousTime = 0;

int tempPin = A6;
int tempVal;
float tempVoltage;
int temperatureC;
int temperatureF;
int tempPreviousTime = 0;

int IR_Pin = 2;
int IR_Val;
int previousIRTime = 0;
volatile float rev = 0;
int oldtime = 0;
int time;
int rpm;
unsigned int mph;
float kmh;

int PreviousSerialTime = 0;
int PreviousClearTime = 0;

int SettingPin = 10;
int SettingSelector;
bool SystemConversion = false;
bool SystemFlag = false;
int PreviousSelectorTime = 0;
bool SelectorPause = false;
bool PreviousSelectorPauseTime = 0;

RTC_DS1307 rtc;
String returnTime() {
  DateTime now = rtc.now();
  int hrs = now.hour();
  String result;

  if (hrs == 0 && hrs != 12) {
    hrs = 12;
  } else if (hrs == 12 && hrs != 0) {
    hrs = 12;
  } else if (hrs < 12 && hrs != 0) {
    hrs = hrs;
  } else if (hrs > 12 && hrs != 0) {
    hrs = hrs - 12;
  }

  result += hrs;
  result += ':';
  result += now.minute(), DEC;
  result += ':';
  result += now.second(), DEC;
  result += " ";

  return result;
  result = "";
}

void InterruptServiceRoutine() { rev++; }

void setup() {
  Serial.begin(9600);
  Wire.begin();

  pinMode(IR_Pin, INPUT);
  pinMode(SettingPin, INPUT);
  attachInterrupt(digitalPinToInterrupt(IR_Pin), InterruptServiceRoutine, RISING);

  lcd.begin(16, 2);
  lcd.clear();

  bool RTC_Flag = false;
  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    RTC_Flag = true;
  }

  if (!rtc.isrunning() && RTC_Flag == false) {
    Serial.println("RTC is NOT running, Time manually set...");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  if (rtc.isrunning() && rtc.begin()) {
    Serial.println("Welcome to Comyar's Bike Speedometer!! It is currently " + returnTime());
    Serial.println("----------------------------------");
    Serial.println();
  }

  lcd.print("Welcome To ");
  lcd.setCursor(0, 1);
  lcd.print("Comyar Bike Tool");
  delay(5000);
  lcd.clear();
}

void loop() {
    SettingSelector = digitalRead(SettingPin);
    int CurrentSelectorTime = millis();
    int CurrentSelectorPauseTime = millis();
    int SelectorSampleRate = 1000;
    int SelectorPauseSampleRate = 500;

    if(CurrentSelectorPauseTime - PreviousSelectorPauseTime >= SelectorPauseSampleRate){
      if(SelectorPause == true && SettingSelector == LOW){
        SelectorPause = false;
      }
        PreviousSelectorPauseTime = CurrentSelectorPauseTime;
    }

    if(CurrentSelectorTime - PreviousSelectorTime >= SelectorSampleRate && SelectorPause == false){
      if(SettingSelector == HIGH){
        if(SystemConversion == false){
          SystemConversion = true;
          SystemFlag = true;
          SelectorPause = true;
        }
        if(SystemConversion == true && SystemFlag == false){
          SystemConversion = false;
          SelectorPause = true;
        }
        SystemFlag = false;
      }
      PreviousSelectorTime = CurrentSelectorTime;
    }

    int IR_Rate = 1000;
    int CurrentIRTime = millis();

    if (CurrentIRTime - previousIRTime >= IR_Rate) {  
      detachInterrupt(digitalPinToInterrupt(IR_Pin));
      int IR_Val = digitalRead(IR_Pin);
      time = millis() - oldtime; 
      rpm = (rev/time) * 60000.0/3; 
      oldtime = millis(); 
      rev = 0;
      mph = (60 * (rpm * (20 * 3.14)))/63360.0;
      kmh = mph * 1.609;
      attachInterrupt(digitalPinToInterrupt(IR_Pin), InterruptServiceRoutine, RISING);

      previousIRTime = CurrentIRTime;
    }

    int tempSampleRate = 500;
    int tempCurrentTime = millis();

    if (tempCurrentTime - tempPreviousTime >= tempSampleRate) {
      tempVal = analogRead(A6);
      tempVoltage = (tempVal / 1024.0) * 5.0;
      temperatureC = (tempVoltage - .5) * 100;
      temperatureC-=4;
      temperatureF = (temperatureC * 1.8) + 32;

      tempPreviousTime = tempCurrentTime;
    }

    int lcdSampleRate = 25;
    int lcdCurrentTime = millis();

    if (lcdCurrentTime - lcdPreviousTime >= lcdSampleRate) {
      lcd.setCursor(0, 1);
      lcd.print("S:");

      lcd.setCursor(6, 0);
      lcd.print("T:" + returnTime());

      if(SystemConversion == false){
        lcd.setCursor(0, 0);
        lcd.print("F:");
        lcd.setCursor(2, 0);
        lcd.print(String(temperatureF) + "*");
      }else{
        lcd.setCursor(0, 0);
        lcd.print("C:");
        lcd.setCursor(2, 0);
        lcd.print(String(temperatureC) + "*");
      }

      lcdPreviousTime = lcdCurrentTime;
    }

    int SerialSampleRate = 25;
    int SerialCurrentTime = millis();

    if(SerialCurrentTime - PreviousSerialTime >= SerialSampleRate){
      if(rpm > 0){
        Serial.println("rpm: " + String(rpm));
        Serial.println("mph: " + String(mph));
      
        lcd.setCursor(2, 1);
        if(SystemConversion == false){
          lcd.print(String(mph) + "mph");
        }else{
          lcd.print(String((int)(kmh)) + "kmh");
        }

        lcd.setCursor(8,1);
        lcd.print("R:" + String(rpm) + "rpm");
      }else{
        lcd.setCursor(2, 1);
        if(SystemConversion == false){
          lcd.print(String(mph) + "mph");
        }else{
          lcd.print(String((int)(kmh)) + "khm");
        }

        lcd.setCursor(8,1);
       lcd.print("R:" + String(rpm) + "rpm");

       PreviousSerialTime = SerialCurrentTime;
    }

    int ClearSampleRate = 250;
    int ClearCurrentTime = millis();

    if(ClearCurrentTime - PreviousClearTime >= ClearSampleRate){
      lcd.clear();
      PreviousClearTime = ClearCurrentTime;
    }
  }
}

Answer 1

Turns out I had a cheap potentiometer. I replaced it and it works good as new.