Unlocking Your Phone's Hidden Magnetometer: A Web App Approach

Have you ever wondered what sensors are lurking inside your smartphone? Beyond the camera and GPS, your device likely houses a magnetometer, a handy tool for measuring magnetic fields. Instead of diving into native app development, let's explore how to access this sensor using a simple web app.

Why Choose a Web App Over Native Development?

Developing native Android or iOS apps can be cumbersome. Here's why a web app might be a better choice for accessing your phone's magnetometer:

• Reduced Overhead: Forget about downloading massive IDEs like Android Studio or Xcode.
• Simplified Development: Web apps offer a lighter, faster development cycle.
• Bypass Developer Mode Restrictions: Avoid enabling Developer Mode, which can impact device security and functionality.

Enabling the Magnetometer API in Chrome

While not yet standardized, Chrome's magnetometer API can be enabled with a simple flag:

1. Type chrome://flags in your address bar.
2. Search for "Generic Sensor Extra Classes."
3. Change the setting from "Default" to "Enabled."

This enables the necessary API for your web app to access magnetometer data. Now, the magnetometer tests on sites like caniuse.com should turn from red to green, indicating successful activation.

The Challenge: Emulating Magnetometer Data

One hurdle in web app magnetometer development is the lack of emulation tools. Unlike accelerometers, neither Chrome developer tools nor Android Studio offers built-in magnetometer data emulation. This means you'll likely need to test directly on a physical device.

Finding Sample Code and Inspiration

Get started with these resources:

• Google Chrome Developer's Blog: Find code snippets and documentation on the Sensor API.
• Intel's "Sensor Info" Web App: Explore a complete web app example from Intel's GitHub account.

By examining Intel's app, you can learn how to add the magnetometer sensor and stream data. This example can serve as a foundation for your own minimalist test app.

Building Your Own Minimalist Magnetometer App

With inspiration from the resources above, you can create a basic web app to display magnetometer data. This project demonstrates the ease of accessing sensor data through web technologies.

The source code for this exploratory project is publicly available on GitHub, allowing you to delve deeper and customize your own magnetometer web app.