Arduino UNO Pressure Measurement - Detailed Example

This example demonstrates how to measure gauge pressure using an Arduino UNO and a sensor with a 0-5V output. The code reads the sensor output and converts the voltage to pressure, displaying it in multiple units:

The sensor’s output voltage corresponds linearly to the gauge pressure.

Detailed Steps

Arduino Code


/*
 * © 2024 Copyright Peter I. Dunne, all rights reserved
 * Prepared for educational use
 * Released under the Mozilla Public License
 * Arduino UNO Pressure Measurement
 * Measures gauge pressure and converts readings to Pascals, kilopascals, bar, PSI, and ATM.
 */

const int pressurePin = A0;    // Pressure sensor connected to A0
const float VRef = 5.0;        // Reference voltage (5V)
const int maxADCValue = 1023;  // 10-bit ADC resolution

// Conversion factors
const float pressureMaxVoltage = 5.0; // Maximum output voltage from the sensor
const float pressureMaxValue = 10.0;  // Maximum pressure value corresponding to 5V (example: 10 bar)

// Conversion constants
const float barToPa = 1e5;    // 1 bar = 100,000 Pa
const float barToPSI = 14.5038; // 1 bar = 14.5038 PSI
const float barToATM = 0.986923; // 1 bar = 0.986923 ATM

// Function to convert voltage to pressure in bar
float voltageToPressure(float voltage) {
    return (voltage / pressureMaxVoltage) * pressureMaxValue;
}

void setup() {
    Serial.begin(115200);  // Start serial communication
    Serial.println("Arduino pressure measurement, by Peter Ivan Dunne, ©2024, all rights reserved");
    Serial.println("Released under the Mozilla Public License");
    Serial.println("https://jazenga.com/educational");
    Serial.println("This demonstration uses 0-5v proportional representation sensors");
    Serial.println("The code must be calibrated for the correct pressure range ");
}

void loop() {
    // Read the analog value from the pressure sensor
    int adcValue = analogRead(pressurePin);

    // Convert ADC value to voltage
    float voltage = (adcValue / float(maxADCValue)) * VRef;

    // Convert voltage to pressure in bar
    float pressureBar = voltageToPressure(voltage);

    // Convert pressure to Pascals, kilopascals, PSI, and ATM
    float pressurePa = pressureBar * barToPa;    // Pascals
    float pressureKPa = pressurePa / 1e3;        // Kilopascals
    float pressurePSI = pressureBar * barToPSI;  // Pounds per Square Inch
    float pressureATM = pressureBar * barToATM;  // Atmospheres

    // Output pressure readings
    Serial.print("Pressure: ");
    Serial.print(pressureBar, 2);
    Serial.print(" bar, ");
    Serial.print(pressureKPa, 2);
    Serial.print(" kPa, ");
    Serial.print(pressurePa, 2);
    Serial.print(" Pa, ");
    Serial.print(pressurePSI, 2);
    Serial.print(" PSI, ");
    Serial.print(pressureATM, 2);
    Serial.println(" ATM");

    delay(1000);  // Delay between readings
}

How It Works