DC Voltmeter need help

Projects Programming
1

Trying to convert the code for a different screen and having no luck at all as Im new to this and could really use some help . designing circuits is what i do but not coding

here is the code that I'm trying to conert for the screen I need

from a Liquid crystal to this U8G2_ST7920_128X64_ any help would be great

====================================================

#include <LiquidCrystal.h>
LiquidCrystal lcd(2,3,4,5,6,7);
 
int ADC_a = 0;              //Analog Input
float VIn_a = 0.0;          //Voltage In after voltage divider
float Voltage_a = 0.0;       //Actual voltage after calculation
float CalVal = 11.1111;           //Voltage divider calibration value

//Timing
unsigned long previousMillis = 0;
const long interval = 200;          //Interval to read voltages

void setup() {
  // put your setup code here, to run once:

  Serial.begin(9600);
  
  lcd.begin(16,2);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Volt Meter");

  pinMode(A0,INPUT);
  pinMode(A1,INPUT);
  
}

void loop() {

   unsigned long currentMillis = millis();
   
   //Timing Loop
    if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;

    ADC_a = analogRead(A0);              //Read analog values
    VIn_a = (ADC_a * 5.0) / 1024.0;     //Convert 10bit input to an actual voltage
    
    Voltage_a = (VIn_a * CalVal);
  //  float v_rounded = ((int) (Voltage_a * 10.0 + 0.5) / 10.0);
    float v_rounded = round(Voltage_a*10)/10;
    
    lcd.setCursor(0,1);
    lcd.print(Voltage_a,1);
    lcd.setCursor(8,1);
    lcd.print(v_rounded);

  } //Timing

} //Loop

=========================================================

2

Do you have any of the library example code working with your display?
"Hello world!" or a smiley face icon?

Please remember to use code tags when posting code

3

here is the code that displays on the screen but I cannot get it to do anything and wont read from pin AO or A1
I removed the old code and replaced it with the one I'm trying to get working.
Thank You
Matthew

4

Do you have any of the library example code working with your display?
"Hello world!" or a smiley face icon?

5

Here is the example that will work with my screen

#include <Arduino.h>
#include <U8g2lib.h>
#include <SPI.h>
#include <Wire.h>

U8G2_ST7920_128X64_1_SW_SPI u8g2(U8G2_R0, 13, 11, 10, 8);

void setup(void) {
  u8g2.begin();
}

void loop(void) {
  u8g2.firstPage();
  do {
    u8g2.setFont(u8g2_font_ncenB14_tr);
    u8g2.drawStr(0,24,"Hello World!");
  } while ( u8g2.nextPage() );
}
6

Replace the loop function with this one

void loop(void) 
{
  u8g2.firstPage();
  char buffer [10];
  sprintf (buffer, "%d", analogRead (A0));
  do {
    u8g2.setFont(u8g2_font_ncenB14_tr);
    u8g2.drawStr(0,24, buffer);
  } while ( u8g2.nextPage() );
}

Please remember to use code tags when posting code, and don't replace code in earlier posts with unrelated code.

7

Thank You for all your help you have been great