Introduction

Every year, millions of old smartphones face a tragic fate—cast aside as e-waste or forgotten in the depths of dusty drawers. Yet, the hardware in these devices often remains perfectly functional! Instead of letting your old Android phone collect dust, why not find a creative and productive way to use it? One exciting solution comes from tech guru Doctor Volt, who recently demonstrated how to repurpose a Samsung Galaxy S4 into a general-purpose input/output (GPIO) controller using an external USB device.

The Concept

The concept is refreshingly simple. By connecting a USB FT232R board to your old phone, the device's Android operating system can recognize the serial adapter. This integration allows you to utilize the phone's processing power in wonderful new projects! In Doctor Volt’s demonstration, the setup was used to blink LEDs and respond to user inputs. However, the potential goes far beyond that—imagine tapping into the phone’s built-in sensors and cameras while launching a variety of DIY projects. You can code these projects in Java/Kotlin or via the Native Development Kit using C or C++.

Charging Considerations

But before you dive in, there's a small catch: while your phone operates in this capacity, charging it is not an option. Fortunately, the Galaxy S4 has a removable battery, making it straightforward to solve this issue by wiring an external power supply with a dummy battery-sized piece of perfboard. If you're using a more modern phone without a removable battery, however, you might be in luck! Many new devices support charging while using simultaneous USB/audio dongles through the USB-C connector—just be sure to double-check compatibility beforehand.

Conclusion

By rejuvenating your old Android phone in this way, not only are you preventing unnecessary e-waste, but you're also unlocking endless possibilities for innovative projects that can enhance your tech skills. Now is the time to dig out that forgotten device and start building something amazing! Don't miss out on the wave of DIY enthusiasm—your old phone could be the key to your next big project!