Getting Started with Barometer

This guide will walk you through integrating the Capacitor Barometer plugin into your application.

Installation

Install the plugin using npm:

npm install @capgo/capacitor-barometer
npx cap sync

iOS Configuration

Add the following to your Info.plist:

<key>NSMotionUsageDescription</key>
<string>This app uses the barometer to measure atmospheric pressure</string>

Android Configuration

No additional configuration required. The plugin automatically requests necessary permissions.

Basic Usage

Import the Plugin

import { Barometer } from '@capgo/capacitor-barometer';

Check Sensor Availability

const checkBarometer = async () => {
  const { available } = await Barometer.isAvailable();
  console.log('Barometer available:', available);
};

Start Monitoring Pressure

const startMonitoring = async () => {
  await Barometer.start({
    interval: 1000 // Update interval in milliseconds
  });

  console.log('Barometer monitoring started');
};

Listen to Pressure Events

Barometer.addListener('pressureChange', (data) => {
  console.log('Pressure (hPa):', data.pressure);
  console.log('Relative altitude (m):', data.relativeAltitude);
  console.log('Timestamp:', data.timestamp);
});

Get Current Reading

const getCurrentPressure = async () => {
  const reading = await Barometer.getCurrentReading();
  console.log('Current pressure:', reading.pressure, 'hPa');
  console.log('Relative altitude:', reading.relativeAltitude, 'm');
};

Stop Monitoring

const stopMonitoring = async () => {
  await Barometer.stop();
  console.log('Barometer monitoring stopped');
};

Complete Example

Here’s a complete example showing barometer integration:

import { Barometer } from '@capgo/capacitor-barometer';

class BarometerService {
  private listener: any;

  async initialize() {
    // Check availability
    const { available } = await Barometer.isAvailable();
    if (!available) {
      console.error('Barometer not available on this device');
      return;
    }

    // Start monitoring
    await Barometer.start({ interval: 1000 });

    // Add listener
    this.listener = Barometer.addListener('pressureChange', (data) => {
      this.handlePressureChange(data);
    });
  }

  handlePressureChange(data: any) {
    console.log('Pressure:', data.pressure, 'hPa');
    console.log('Altitude:', data.relativeAltitude, 'm');

    // Update UI or process data
    this.updateDisplay(data);
  }

  updateDisplay(data: any) {
    // Convert hPa to other units
    const inHg = (data.pressure * 0.02953).toFixed(2);
    const mmHg = (data.pressure * 0.750062).toFixed(1);

    console.log(`Pressure: ${data.pressure.toFixed(1)} hPa`);
    console.log(`         ${inHg} inHg`);
    console.log(`         ${mmHg} mmHg`);
    console.log(`Altitude: ${data.relativeAltitude.toFixed(1)} m`);
  }

  async cleanup() {
    // Remove listener
    if (this.listener) {
      this.listener.remove();
    }

    // Stop monitoring
    await Barometer.stop();
  }
}

// Usage
const barometerService = new BarometerService();
barometerService.initialize();

// Cleanup when done
// barometerService.cleanup();

Understanding Readings

Atmospheric Pressure

• Measured in hectopascals (hPa) or millibars (mb)
• Standard sea-level pressure: 1013.25 hPa
• Higher altitude = lower pressure
• Weather systems affect pressure readings

Relative Altitude

• Calculated from pressure changes
• Relative to starting reference point
• Accuracy: ±10-30 meters
• Works best for short-term tracking

Best Practices

1. Check Availability: Always verify sensor availability before use
2. Reasonable Intervals: Don’t poll too frequently (1000ms is good)
3. Remove Listeners: Clean up listeners when not needed
4. Calibration: Use known altitude for accurate readings
5. Battery Impact: Monitor battery usage with continuous sensing

Common Issues

Sensor Not Available

try {
  const { available } = await Barometer.isAvailable();
  if (!available) {
    // Fallback to GPS altitude or manual input
    showAlternativeMethod();
  }
} catch (error) {
  console.error('Barometer check failed:', error);
}

Noisy Data

class PressureFilter {
  private readings: number[] = [];
  private maxReadings = 5;

  addReading(pressure: number): number {
    this.readings.push(pressure);
    if (this.readings.length > this.maxReadings) {
      this.readings.shift();
    }

    // Return moving average
    const sum = this.readings.reduce((a, b) => a + b, 0);
    return sum / this.readings.length;
  }
}

Next Steps

• Explore the API Reference for complete method documentation
• Check out the example app for advanced usage
• See the tutorial for complete implementation examples