Arduino Project: Pulse-Based Motor Control with LCD Display

Description

This Arduino-based project controls a 12V water pump using pulse counting and a push button. It displays credit values on an I2C LCD screen and activates the pump when a specific amount is reached.

Components Used

• Arduino Micro – Microcontroller to handle logic and control
• L298N Motor Driver – Controls the 12V water pump
• 12V Water Pump – Activated when sufficient credits are collected
• Push Button – Used to manually trigger the pump
• LCD Display (16x2) with I2C Module – Displays credit balance
• Coin Selector – Generates pulses based on inserted coins
• Resistors and Wires – Additional electronic components for connections

How It Works

1. The system continuously monitors pulses received from the coin selector.
2. Each pulse corresponds to R$ 0.25, and after 12 pulses (R$ 3.00), the system becomes ready to activate the pump.
3. The accumulated credit is displayed on the LCD.
4. When the push button is pressed after collecting R$ 3.00, the pump activates for 5 seconds.
5. After activation, the pulse counter resets to zero, and the system waits for new pulses.

Code Breakdown

Libraries and LCD Initialization

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2); // Initialize LCD with I2C address 0x27

Pin Definitions

int IN1 = 9;  // Motor 1 (Pump)
int IN2 = 10;
int ENA = 4;  // Pump speed control (PWM)

int buttonPin1 = 12; // Push button for activation
int pulsePin = 7;    // Coin selector pulse input pin

Variables for Pulse Counting

volatile int pulseCount = 0;   // Pulse counter
bool pulseReady = false;
unsigned long lastPulseTime = 0;
unsigned long pulseDebounceTime = 100; // Minimum time between pulses (ms)

Pulse Counting Function

void countPulse() {
  unsigned long currentTime = millis();
  if (currentTime - lastPulseTime > pulseDebounceTime) { // Debounce filter
    pulseCount++;
    lastPulseTime = currentTime;
    Serial.print("Pulses counted: ");
    Serial.println(pulseCount);
    if (pulseCount >= 12) { // 12 pulses equal R$ 3.00
      pulseReady = true;
      Serial.println("12 pulses received! Ready to activate the pump.");
    }
  }
}

Setup Function

void setup() {
  Serial.begin(9600);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(ENA, OUTPUT);
 
  pinMode(buttonPin1, INPUT_PULLUP);
  pinMode(pulsePin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(pulsePin), countPulse, FALLING);

  lcd.init();
  lcd.setBacklight(HIGH);
}

Main Loop

void loop() {
  lcd.setCursor(0,0);
  lcd.print(" Value R$ 3.00");
  float value = pulseCount * 0.25; // Convert pulses to monetary value
  lcd.setCursor(0,1);
  lcd.print("Credits:R$ ");
  lcd.print(value, 2); // Display with two decimal places

  if (!pulseReady) return; // Do nothing if 12 pulses are not reached

  if (digitalRead(buttonPin1) == LOW) {
    Serial.println("Button pressed, activating Pump");
    analogWrite(ENA, 200);
    digitalWrite(IN1, HIGH);
    digitalWrite(IN2, LOW);
    delay(5000);
    digitalWrite(IN1, LOW);
    digitalWrite(IN2, LOW);
    pulseReady = false;
    pulseCount = 0;
    Serial.println("Pump deactivated, waiting for new pulses");
  }
}

Summary

• The system counts pulses from the coin selector and converts them into monetary credit.
• When R$ 3.00 is reached, the system allows pump activation through a push button.
• Pressing the button activates the 12V water pump for 5 seconds.
• The system resets and waits for new pulses.

This setup can be used for coin/token-based water dispensing machines, vending machines, or prepaid systems that require pulse-based credit tracking.

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Wiring Diagram

Demonstration

To see the system in action, add a GIF here showing the coin selector, LCD updates, and pump activation.