5 Weird Gadgets You Can Plug Into Your Headphone Jack

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The purpose of a headphone jack seems simple, obvious, and perhaps self-explanatory — you use it to plug your headphones in. But that doesn't have to be where the fun ends. Your headphone jack is actually a 3.5mm auxiliary port, designed to carry audio signals to all kinds of different devices and quirky gadgets. You might've already noticed that microphones work through some of them, like the microphone that's built into your gaming headset, but with the right gadgets, you can use your , run a , or

Considering the fact that most of the best headphones work over Bluetooth now, it makes sense that you might want to make the most of your 3.5 mm jack with something else entirely. Even though the auxiliary jack is designed with audio signals in mind, not every gadget that runs through it is audio-related. For example, can plug straight into the headphone jack on your phone — assuming your phone still has a headphone jack – to create an on-the-go payment system.

Apps like GarageBand make it easier than ever to make music on your iPad or iPhone, but what isn't always so easy is figuring out how to record high-quality audio directly through your phone or tablet in order to do so. range sets out to help with that by leveraging your device's built-in inputs to create a line-in for you to plug your guitar or bass directly into, allowing your phone's app or software to record the audio signal. Simply put, it captures what you play on guitar or bass by turning your phone into an interface.

Some later editions of the iRig, like the , run through different inputs like your phone's USB-C port. However, you can still easily pick up its 3.5mm counterpart, the iRig 2, to run through your headphone jack. It's designed for the Apple ecosystem, meaning it runs with an iPhone, iPad, Mac, or even that old iPod Touch you might have lying around. As well as working with you can also use the iRig to turn your phone into a multi-effects processor. This means you can use it to apply audio effects to your guitar or bass whenever you want to, like you would if you were using a board of effects pedals.

If you've visited a market or a small business at some point in the past few years, it's more than likely that you've already come across a mobile payment system in person. For the most part, you've probably either been tapping your card on a contactless terminal or putting it into a wireless device and jamming your PIN in. What you might not have seen yet is a swipe system plugged into a phone or tablet's aux port. Which is perhaps for good reason — you don't want to swipe too hard and accidentally snap the reader off at the port.

When you look at your headphone jack, you probably don't see the immediate potential of turning it into a card reader. However, that's exactly what is for. All you need to do is plug the tiny gadget into your smartphone's headphone jack and run the Square Point of Sale app to turn your device into a chip card reader to take payments anywhere with an internet connection. More recently, but you can still pick up the headphone jack version on the

Surprisingly, with the right gadgets and apps, you can temporarily turn your phone into a counter. are electronic devices that measure ionizing radiation through a clever set of internal mechanisms and data sonification, and usually, they're pretty large and cumbersome to lug around. However, this tiny Geiger counter is around the size of your pinky finger, and it works using the headphone jack on your Android smartphone.

The Smart Geiger Pro claims to measure Gamma and Beta radiation found in the atmosphere or nearby objects using ten built-in semiconductor sensors, with a margin of error of around 15%. All you need to do is plug it into your aux port for a couple of minutes, hold still, and run the designated Smart Geiger Pro app to get a quick reading on your screen. Naturally, if you're planning on venturing into somewhere that may be unsafe, you should consider relying on a full Geiger counter instead of a gadget. But, this could be a fun gadget for a quick science experiment — or a rather handy find if you and want to check if that piece of antique furniture or table set you like is secretly slightly radioactive.

Despite what the gadget's name might suggest, the has nothing to do with "" at all. In actuality, it's a motor and LED light controller you can connect to your Android smartphone via its headphone jack. The device has an unassuming, Raspberry Pi-like appearance featuring exposed circuitry and a surprisingly useful auxiliary output used to connect the device to a smartphone via a jack-to-jack or auxiliary cable. Once hooked up to your phone, it runs using an app that allows you to control up to eight servo motors and eight LEDs at once.

The app uses a visual , meaning you don't need to write any code to use the ServoDroid to control your own projects. Instead, you drag-and-drop different functions, and control your devices using the on-screen interface. Since the ServoDroid is designed to work with specific types of motors and components, exactly what you can control with it really depends on what you want to build. For example, you could use it to control the movements of a mechanical camera mount to make your webcam pivot while filming, or use it to dim lights on demand. Or, if you're an experienced builder, you robots.

One of the weirdest headphone jack gadgets out there is also, in a way, one of the most straightforward. Meet , a microphone built for you to stick straight into a 3.5 mm jack. You'd be forgiven if, at first glance, you thought this was the kind of mobile microphone you see all of the time in vox pops and mini vlogs on TikTok. However, this specialized microphone is actually built for ghost hunting.

This otherworldly microphone is designed with something called the in mind. This phenomenon can include noises, sounds, and artefacts found in audio recordings that some interpret relate to hauntings or paranormal activity. Electronic voice phenomena are investigated and recorded by ghost-hunters and paranormal enthusiasts using various types of audio equipment, including microphones, tape recorders, and equipment.

The gadget offers an X/Y stereo recording set up, meaning it captures audio from the left and right in two separate audio channels when used with suitable recording software. It also offers a frequency response ranging from 100 to 15,000 hertz, essentially meaning it can pick up sound within that frequency range. The EVP microphone is definitely an unusual gadget — there's just no guarantee you'll definitely find a ghost with it.