← Back to overview
Project note

Arduino Watering project - Distanse module

Arduino Watering project - Distanse module: Measure the water level in a barrel using an ultrasonic distance sensor and indicate the level on an LCD. • IoT • arduino, pcb

5 tags
Tags

🎯 Purpose

Measure the water level in a barrel using an ultrasonic distance sensor and indicate the level on an LCD.

🧩 How it works (quick logic)

  • If measured distance < 10 cm → show “< 10 cm water”.
  • If measured distance ≥ 10 cm → show “10 > cm water”.

🖼️ First prototype (program + display)

image

🎥 Threshold demo (< 10 cm vs ≥ 10 cm)

🔧 Mechanical updates

  • New bracket/foot for the sensor module and tidier mounting.

image image image image

🌲 Manifold & tank

Each hole in the “tree” block represents a water pipe to its own pump.

image

The water tank:

image image image

🧠 Wiring & PCB

Full build with cables and a PCB board:

image image

I needed an extra-long cable, so I soldered my own and added strain relief.

image image

A friend suggested heat-shrink tubing — worked great:

image

💻 Firmware (Arduino)

Drives two LCD sizes via TCA9548A I²C multiplexer and reads the ultrasonic sensor (HC-SR04-style) on trigPin=7, echoPin=8.

cpp
#include "Wire.h"                 // For I2C
#include "LCD.h"                  // For LCD
#include "LiquidCrystal_I2C.h"    // Added library
#define TCAADDR 0x70              // TCA9548A encoder address

LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); // Set the LCD

/* -----( Declare Constants )----- */
byte AwithRing[8] = { // å
  B00100, B01010, B01110, B00001, B01111, B10001, B01111,
};
byte AwithDots[8] = { // ä
  B01010, B00000, B01110, B00001, B01111, B10001, B01111,
};
byte OwithDots[8] = { // ö
  B01010, B00000, B01110, B10001, B10001, B10001, B01110,
};
byte BigAwithRing[8] = { // Å
  0b00100, 0b01010, 0b01110, 0b10001, 0b11111, 0b10001, 0b10001, 0b00000
};
byte BigAwithDots[8] = { // Ä
  0b01010, 0b00000, 0b01110, 0b10001, 0b11111, 0b10001, 0b10001, 0b00000
};
byte BigOwithDots[8] = { // Ö
  0b01010, 0b01110, 0b10001, 0b10001, 0b10001, 0b10001, 0b01110, 0b00000
};

// Water tank
const int trigPin = 7; // trigger pin
const int echoPin = 8; // echo pin
long duration, cm;

// Letters/messages
String Message_1 = "Mindre &auml;n 5%";
String Message_2 = "Mindre 20%";
String Message_3 = "Mindre &auml;n 75%";
String Message_4 = "Mer &auml;n 75%";
String Message_end = "Vatten i tank";

void setup() {
  Serial.begin(9600);
  screenBig();
  screenSmallOne();
}

void loop() {
  // Define inputs and outputs
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  delay(10000);
  screenSmallTank();
}

void tcaselect(uint8_t i) {
  if (i > 7) return;
  Wire.beginTransmission(TCAADDR);
  Wire.write(1 << i);
  Wire.endTransmission();
}

void screenBig() {
  Wire.begin();
  tcaselect(2);
  lcd.begin(20, 4);
  lcd.setCursor(3, 0); lcd.print("This is a test");
  lcd.setCursor(8, 1); lcd.print("****");
  lcd.setCursor(3, 2); lcd.print("XsiSec is best");
  lcd.setCursor(8, 3); lcd.print("****");
}

void screenSmallOne() {
  Wire.begin();
  tcaselect(3);
  lcd.begin(16, 4);
  lcd.setCursor(3, 0); lcd.print("This is a test");
  lcd.setCursor(8, 1); lcd.print("****");
  lcd.setCursor(3, 2); lcd.print("XsiSec is best");
  lcd.setCursor(8, 3); lcd.print("****");
}

void screenSmallTank() {
  tcaselect(4);
  lcd.begin(16, 4);

  lcd.createChar(1, AwithRing);     // å
  lcd.createChar(2, AwithDots);     // ä
  lcd.createChar(3, OwithDots);     // ö
  lcd.createChar(4, BigAwithRing);  // Å
  lcd.createChar(5, BigAwithDots);  // Ä
  lcd.createChar(6, BigOwithDots);  // Ö

  lcd.setCursor(1, 0);

  Message_1.replace("&auml;", "\2");
  Message_2.replace("&auml;", "\2");
  Message_3.replace("&auml;", "\2");
  Message_4.replace("&auml;", "\2");

  digitalWrite(trigPin, LOW);  delayMicroseconds(0);
  digitalWrite(trigPin, HIGH); delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
  cm = (duration / 2) / 29.1; // or * 0.0343

  if (cm < 5) {
    lcd.print(Message_1);
    lcd.setCursor(1, 1); lcd.print(Message_end);
  } else if (cm < 10) {
    lcd.print(Message_2);
    lcd.setCursor(1, 1); lcd.print(Message_end);
    lcd.setCursor(8, 1);
  } else if (cm < 15) {
    lcd.print(Message_3);
    lcd.setCursor(1, 1); lcd.print(Message_end);
  } else if (cm > 15) {
    lcd.print(Message_4);
    lcd.setCursor(1, 1); lcd.print(Message_end);
  }
}

void measureDistance() {
  digitalWrite(trigPin, LOW);  delayMicroseconds(0);
  digitalWrite(trigPin, HIGH); delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
  cm = (duration / 2) / 29.1;
  delay(1000);
}

🖥️ LCD output (how it looks)

image image

🔬 Sensor close-up

image

📏 Desktop → station distance (lift test)