Portable Air Compressor with Auto Cutoff

Portable Air Compressor with Auto Cutoff

How It Works

• A pressure sensor/transducer mounted on the tank continuously reports current pressure to the controller.
• The controller compares the reading against a preset upper threshold; on reaching it, a relay cuts power to the compressor motor.
• If pressure later drops below a preset lower threshold (from air being used), the controller re-energizes the relay and restarts the motor automatically — maintaining pressure within a working band without manual switching.
• Current pressure is shown on an LCD/OLED display so the user always has a live reading, and a mechanical relief valve provides a hardware safety backstop independent of the electronics.

Components

Arduino/microcontroller
Pressure sensor/transducer (tank-rated)
Motor-rated relay module
Portable compressor motor + pump unit
LCD/OLED display (pressure readout)
Air tank + mechanical safety relief valve

Applications

• Spray painting setups
• Tire inflation stations
• Pneumatic hand tools in small workshops
• Field/portable compressed-air use

Advantages

• Prevents overpressure damage or hazard automatically
• Saves energy versus a compressor left running continuously
• Automatic restart on the low threshold keeps the tank ready without manual attention
• Portable form factor suited to field and small workshop use

Sample Code — Pressure Threshold Relay Control with Hysteresis

// Simplified pressure-threshold auto cutoff - Arduino
int pressurePin = A0;
int compressorRelay = 7;
float upperLimitPSI = 120.0;
float lowerLimitPSI = 100.0;
bool motorRunning = false;

float readPressurePSI() {
  int raw = analogRead(pressurePin);
  return raw * (150.0 / 1023.0); // calibrate to sensor's rated range
}

void setup() {
  pinMode(compressorRelay, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  float pressure = readPressurePSI();
  Serial.println(pressure);

  if (motorRunning && pressure >= upperLimitPSI) {
    digitalWrite(compressorRelay, LOW);  // cut power - limit reached
    motorRunning = false;
  } else if (!motorRunning && pressure <= lowerLimitPSI) {
    digitalWrite(compressorRelay, HIGH); // restart - pressure dropped
    motorRunning = true;
  }
  delay(300);
}

Related Research

• Compressor Air Pressure Monitoring Through Wireless Communication System — IJERT