Arduino Based Automatic Tire Inflator Using Pressure Sensor, Relay Module and LCD Display

This Arduino-based Automatic Tire Inflator is a smart air pressure control system designed to automatically inflate vehicle tires to a preset pressure level. The system uses a pressure sensor to monitor tire pressure in real time and controls an air compressor through a relay module, ensuring accurate and safe inflation. A 16x2 LCD display provides live pressure readings and system status updates.

Project Overview

This automatic tire inflation system includes:

Arduino UNO microcontroller
Pressure sensor (air pressure transducer) for PSI measurement
4-channel relay module (used to control air compressor and other outputs)
Air compressor / DC pump
16x2 LCD display for real-time pressure display
Buzzer for alert notification
Push buttons for setting desired pressure
SMPS power supply with DC-DC buck converter
Supporting wiring and connectors

How It Works

The pressure sensor continuously measures tire air pressure.
The Arduino compares the measured pressure with the preset target value.
If the pressure is below the set limit:
- The relay module activates the air compressor.
When the desired pressure is reached:
- The compressor automatically turns OFF.
- The buzzer gives a confirmation alert.
The LCD display shows:
- Current tire pressure (PSI/Bar)
- Set pressure value
- System status (Inflating / Completed)

Key Features

Automatic inflation control
Real-time tire pressure monitoring
Over-inflation protection
Relay-controlled air compressor
LCD-based user interface
Safe and energy-efficient operation
Suitable for cars, bikes, and bicycle

Code:

#include <EEPROM.h>
#include <LiquidCrystal_I2C.h>
#include <Wire.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);  //Device Address,N Charecter, LCD Lines
//SDA-> A4 SCL-> A5

int sensorPin = A0;
int setvalue = 0;

int sw_set = 2; //Connect to Switch Set
int sw_up = 3; //Connect to Switch UP
int sw_dwn = 4; //Connect to Switch Down
int sw_ent = 5;//Connect to Switch Enter

int purge = 6; //For Solenoid
int feed = 7; //For Solenoid

int max_pressure = 70;
int min_pressure = 10;
int pressure_value = 0;
int sensor_Value = 0;
int cal_factor = 0;
int set_mode = 0;
int threshold = 5;

int inf_delay = 200;
String disp_string[4] = { "  Tyre Inflator", "Set Pressure", "-", "-" };
void setup() {
  // declare the ledPin as an OUTPUT:
  //pinMode(ledPin, OUTPUT);
  pinMode(purge, OUTPUT);
  pinMode(feed, OUTPUT);
  pinMode(sw_up, INPUT_PULLUP);
  pinMode(sw_dwn, INPUT_PULLUP);
  pinMode(sw_set, INPUT_PULLUP);
  pinMode(sw_ent, INPUT_PULLUP);

  Serial.begin(9600);
  load_settings(set_mode);
  delay(500);

  if (setvalue > max_pressure) {
    save_settings(set_mode, 23);
  }
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(6, 0);
  lcd.print("Welcome");
  lcd.setCursor(4, 1);
  lcd.print("Automatic");
  lcd.setCursor(2, 2);
  lcd.print("Tyre Inflator");
  delay(3000);
  lcd.clear();
  disp_string[1] = "Set Pres.:" + String(setvalue) + "PSI";
  disp_string[2] = "Press Enter";
  disp_string[3] = "To Start Inflating";
  display();
}

void loop() {
  if (set_mode == 1) {
    sensor_Value = analogRead(sensorPin);
    pressure_value = sensor_Value + cal_factor;
    disp_string[2] = "Set Pressure:" + String(setvalue) + "PSI";
    disp_string[3] = "Tyre Pressure:" + String(pressure_value) + "PSI";
    delay(5);

    if (pressure_value < (setvalue + threshold)) {
      delay(inf_delay);
      if (pressure_value > setvalue) {
        //Stop Inflating
        disp_string[1] ="Inflation Done";
        digitalWrite(purge, HIGH);
        digitalWrite(feed, HIGH);
      } else {
        //inflating
        disp_string[1] ="****Inflating****";
        digitalWrite(purge, HIGH);
        digitalWrite(feed, LOW);
      }
    }

    if (pressure_value > (setvalue + threshold)) {
      delay(inf_delay);
      if (pressure_value > setvalue) {
        //Purging
        disp_string[1] ="****Purging****";
        digitalWrite(purge, LOW);
        digitalWrite(feed, HIGH);
      } else {
        //Stop Purging
        disp_string[1] ="Purging Done";
        digitalWrite(purge, HIGH);
        digitalWrite(feed, HIGH);
      }
    }
    
    display();
  } else {
    digitalWrite(purge, LOW);
    digitalWrite(feed, LOW);
  }

  if (digitalRead(sw_up) == LOW) {
    delay(1000);
    switch (set_mode) {
      case 0:
        if (setvalue < max_pressure) {
          setvalue += 1;
          delay(10);
          save_settings(set_mode, setvalue);
          disp_string[2] = "Set Pressure:" + String(setvalue) + "PSI";
          display();
        }
        break;
      case 2:
        if (cal_factor < 200) {
          cal_factor += 1;
          delay(10);
          save_settings(set_mode, cal_factor);
          sensor_Value = analogRead(sensorPin);
          pressure_value = sensor_Value + cal_factor;
          disp_string[2] = "Cal. Factor: " + String(cal_factor);
          disp_string[3] = "Pressure:" + String(pressure_value) + "PSI";
          display();
        }
        break;
    }
  }
  if (digitalRead(sw_dwn) == LOW) {
    delay(1000);
    switch (set_mode) {
      case 0:
        if (setvalue > min_pressure) {
          setvalue -= 1;
          delay(10);
          save_settings(set_mode, setvalue);
          disp_string[2] = "Set Pressure:" + String(setvalue) + "PSI";
          display();
        }
        break;

      case 2:
        if (cal_factor > 1) {
          cal_factor -= 1;
          delay(10);
          save_settings(set_mode, cal_factor);
          sensor_Value = analogRead(sensorPin);
          pressure_value = sensor_Value * (cal_factor / 100);
          disp_string[2] = "Cal. Factor: " + String(cal_factor);
          disp_string[3] = "Pressure: " + String(pressure_value) + "PSI";
          display();
        }
        break;
    }
  }


  if (digitalRead(sw_set) == LOW) {
    delay(1000);
    set_mode = 0;  //Pressure Setting
    disp_string[1] = "Pressure Setting..";
    display();
  }

  if (digitalRead(sw_ent) == LOW && digitalRead(sw_set) == HIGH) {
    delay(1000);
    set_mode = 1;  //Running
    lcd.clear();
  }

  if (digitalRead(sw_ent) == LOW && digitalRead(sw_set) == LOW) {
    delay(1000);
    set_mode = 2;  //Clibration
    lcd.clear();
    disp_string[1] = "Sensor Calibration";
    display();
  }
}

void standby() {
  digitalWrite(purge, LOW);
  digitalWrite(feed, LOW);
  lcd.clear();
  disp_string[1] = "Set Pres.:" + String(setvalue) + "PSI";
  disp_string[2] = "Press Enter";
  disp_string[3] = "To Start Inflating";
  display();
}

void display() {
  //lcd.clear();
  for (int i = 0; i < 4; i++) {
    lcd.setCursor(0, i);
    delay(1);
    lcd.print(disp_string[i]);
    Serial.println("L" + String(i) + ": " + disp_string[i]);
    delay(5);
  }
}

void save_settings(int address, int value) {
  EEPROM.write(address, value);
  EEPROM.update(address, value);
}

void load_settings(int address) {
  setvalue = EEPROM.read(address);
}

Applications

Smart vehicle maintenance systems
Automated air filling stations
Portable digital tire inflator
Industrial pneumatic pressure control
DIY automotive electronics projects

This Arduino Automatic Tire Inflator System is ideal for automotive automation projects, embedded systems learning, and smart vehicle maintenance solutions.

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