LCD flickering with ethernet

Projects Programming
7

I think I'm getting there (almost). The ultimate goal is that the LCD is "only" updated every 5 minutes or so (no need to have the water level updated too regularly), and that the web page should always have that last update. In the code below I put the update interval to 10 seconds.

Two more questions:

  1. Actually reading the sensor should be a separate function too ? With the result (CurVol and CurPercentage) passed on to update the LCD and update the web page ? I tried that but doesn't seem to work properly if I try to return the values.
  2. The client connection to the webserver can happen anytime during those 5 minutes. Is it OK then to have that run every second, so it can pick up the incoming client request?
#include <HCSR04.h>
#include <Wire.h>
#include "rgb_lcd.h"
#include <SPI.h>
#include <Ethernet.h>
#include <ArduinoJson.h>

// HC-SR04
UltraSonicDistanceSensor distanceSensor(15, 14);

// 16x2 LCD
rgb_lcd lcd;

// Wired Ethernet
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(192, 168, 0, 30); // static IP not working due to changed ESP32/server.h
IPAddress gateway(192, 168, 0, 1);
IPAddress subnet(255, 255, 255, 0);
EthernetServer server(80);

// Variables
int MaxHeight = 200; //height of water tank
int MaxVol = 20000; //max vol in L of both water tanks
int CurVol = 0;
int CurPercentage = 0;
// Progress Bar characters
byte zero[] = {B00000, B00000, B00000, B00000, B00000, B00000, B00000, B00000};
byte one[] = {B10000, B10000, B10000, B10000, B10000, B10000, B10000, B10000};
byte two[] = {B11000, B11000, B11000, B11000, B11000, B11000, B11000, B11000};
byte three[] = {B11100, B11100, B11100, B11100, B11100, B11100, B11100, B11100};
byte four[] = {B11110, B11110, B11110, B11110, B11110, B11110, B11110, B11110};
byte five[] = {B11111, B11111, B11111, B11111, B11111, B11111, B11111, B11111};

// Function to connect to Ethernet & start server
void setupEthernet () {
  Ethernet.init(33);
  Ethernet.begin(mac, ip, gateway, subnet);
  delay(1000);
  server.begin();
  Serial.println(F("Server is ready."));
  Serial.print(F("Please connect to http://"));
  Serial.println(Ethernet.localIP());
}

// Function to setup LCD screen
void setupLcd () {
  lcd.begin(16, 2);
  lcd.createChar(0, zero);
  lcd.createChar(1, one);
  lcd.createChar(2, two);
  lcd.createChar(3, three);
  lcd.createChar(4, four);
  lcd.createChar(5, five);
  lcd.clear();
}

void updateLCD(int CurPercentage, unsigned long totalCount, int lineToPrintOn, int CurVol) {
  static unsigned long timer = 0;
  unsigned long interval = 10000;
  if (millis() - timer >= interval) {
    timer = millis();
    // Show progress bar on LCD
    double factor = totalCount / 80.0;  // 16 characters x 5
    int percent = (CurPercentage + 1) / factor;
    int number = percent / 5;
    int remainder = percent % 5;
    if (number > 0) {
      for (int j = 0; j < number; j++) {
        lcd.setCursor(j, lineToPrintOn);
        lcd.write(5);
      }
    }
    lcd.setCursor(number, lineToPrintOn);
    lcd.write(remainder);
    if (number < 16) {
      for (int j = number + 1; j <= 16; j++) {
        lcd.setCursor(j, lineToPrintOn);
        lcd.write((byte)0x00);
      }
    }
    // show current volume and percentage on LCD
    lcd.setCursor(0, 0);
    lcd.print("                ");
    lcd.setCursor(1, 0);
    lcd.print(CurVol);
    lcd.print(" L - ");
    lcd.print(CurPercentage);
    lcd.print(" %");
  }
}

void doEthernet(int CurPercentage) {
  static unsigned long timer = 0;
  unsigned long interval = 1000;
  if (millis() - timer >= interval) {
// Wait for an incoming connection
  EthernetClient client = server.available();
  if (!client)
  return;
  //Serial.println(F("New client"));
  while (client.available()) client.read();
  StaticJsonDocument<100> doc;
  doc["data"] = CurPercentage;
  // Write response headers
  client.println(F("HTTP/1.0 200 OK"));
  client.println(F("Content-Type: application/json"));
  client.println(F("Connection: close"));
  client.print(F("Content-Length: "));
  client.println(measureJsonPretty(doc));
  client.println();
  serializeJsonPretty(doc, client);
  client.stop();
  }
}
// ========== MAIN FUNCTIONS: SETUP & LOOP ==========
void setup () {

  Serial.begin(9600);
  setupLcd (); 
  lcd.print("(re)Starting...");
  setupEthernet(); // Connect to Ethernet
  delay(5000);
  lcd.clear();
}

void loop () {

  float inputReading = distanceSensor.measureDistanceCm();
  int CurPercentage = (100 - (inputReading / MaxHeight * 100));
  int CurVol = MaxVol / 100 * CurPercentage;
  updateLCD(CurPercentage, 100, 1, CurVol);
  doEthernet(CurPercentage);
  
}