When you think of the 3.5 mm headphone jack, chances are you picture earbuds or maybe an old aux cable in the car. But beyond audio, this little port is used in a wide range of accessories—some practical, some unusual, and all surprisingly clever.
6
Flashlight
Handy if your smartphone light stops working
The audio jack on phones isn’t only useful for headphones. There are flashlights designed to plug straight into a 3.5 mm headphone jack and can turn your phone, tablet, or other compatible gadget into a portable light source.
Portable 3.5 mm jack lights are a rare find these days, much like headphone jacks themselves on modern smartphones. These flashlights are tiny, making them perfect for slipping into your pocket, attaching to a keychain, or stashing in your bag for emergencies.
Using one is as simple as plugging it into your device and flipping the switch. Your phone instantly becomes a torch, ready to illuminate the night. This can be useful during camping trips, late-night walks, or any situation where a quick, hands-free light source comes in handy. Of course, you can also use it for capturing great photos in low-light conditions.
5
Camera button
No more worrying about smiling for a timer
While using a camera, you may not always be able to hit the shutter button easily. This is especially true when you’re recording yourself.
Fortunately, there are camera shutter remotes that connect to your DSLR or mirrorless camera via a 3.5 mm to N3 cable. One end plugs into the camera’s port, while the other connects to the remote’s 3.5mm jack. You can then snap photos or start recording without touching the camera.
This works for smartphones too. In fact, many selfie sticks and remote shutter accessories use a wired, 3.5 mm connection to trigger the phone’s camera. That way, you can easily snap selfies or record a vlog with your phone mounted on the stick.
4
Thermometer
Perfect meat every time… with your smartphone
One of the more unusual gadgets that uses a 3.5 mm headphone jack is a thermometer. But this isn’t for checking if you have a fever. Instead, it’s for making sure your meat is cooked to perfection.
Tiny meat thermometers plug into grills and smokers, turning them into a precision cooking station. The probe slides into your steak or chicken, while the other end connects to your cooking device to deliver real-time temperature readings.
A similar gadget is the Bayite NTC 10K Temperature Controller Probe Sensor. This small probe acts as a remote temperature sensor for compatible controllers such as the Bayite BTC 201 or BTC 211.
It sends accurate readings to the controller, which then adjusts heating or cooling equipment as needed. These devices are especially useful for brewing, maintaining aquariums, managing a greenhouse, or handling other DIY projects.
3
Card readers
Never get caught short when you need to take a payment
The headphone jack on your phone or tablet can also be used as a mini payment terminal. EMV chip card readers are tiny devices that plug straight into your phone or tablet’s audio jack, so you can accept credit and debit card payments on the go.
Once plugged in, the device works with a companion app on your phone or tablet to process payments securely and efficiently, just like a full-sized point-of-sale system. You can either swipe the card or use contactless tap payments.
These compact readers are popular with small business owners, market vendors, and freelancers who need a portable, hassle-free way to handle transactions.
2
Stylus
It makes certain tasks so much easier
If your phone or tablet doesn’t have a built-in stylus, but you like the benefits these specialized pens offer, carrying a separate one can be tricky. Fortunately, tiny Stylus Pens are available that plug directly into a 3.5 mm headphone jack. The jack doubles as a convenient holder, so you don’t have to worry about losing the stylus or digging through your bag.
These mini-styluses are especially handy for using your device while wearing gloves, whether due to cold weather or work conditions. Of course, you can use them with any touchscreen device, including laptops, smart home displays, car infotainment systems, and more.
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IR cable extender
This is a surprisingly useful gadget to keep around
An IR Cable Extender lets you transmit invisible IR remote control signals from devices like Xbox, Apple TV, or other home theater equipment to devices that are tucked away inside cabinets or hidden behind walls.
The way it works is simple. The extender takes the signal from your remote or IR repeater and sends it through the cable to small emitter heads. These emitters then beam the signal to the target device. This allows you to control the device even when it’s completely out of sight.
It’s a clever solution for anyone who wants a sleek living room while still being able to command their tech with ease.
The next time you see a lonely headphone jack, don’t just think about audio. From meat thermometers and flashlight attachments to camera remotes, styluses, and even EMV card readers, these quirky little gadgets prove that the 3.5 mm port is a true multitasker.