Which USB gadgets actually work with your smart TV

A smart TV USB port is best at playing your own files. Almost every model can open photos, music and video from a flash drive, which is handy when the internet is down or you want to show holiday pictures to the family without casting from a phone.

Bigger storage often works too. Many TVs will read an external hard drive or SSD, which holds far more than a stick, as long as the drive doesn’t need more power than the port can give. Some sets have a faster USB 3.0 port, which copes better with large 4K video files.

A smaller group of TVs supports PVR (personal video recorder) through USB. That lets you record live broadcasts onto a drive. Expect limits: many streaming apps block recording entirely, so this is mainly for over-the-air or cable channels.

Simple plug-and-go devices are the safest bet. Many TVs recognize a USB keyboard and mouse, which beats spelling out a password one letter at a time with the remote. A wireless keyboard with a built-in touchpad, such as the Logitech K400 Plus, also helps if your TV has a web browser. You’ll still need the remote for some settings, so the keyboard is an extra, not a replacement.

Other gadgets that commonly work include:

• Game controllers: wired USB pads work on some TVs, though Bluetooth is the more common way to connect them.
• USB microphones: many TVs accept one for clearer voice commands.
• LED backlight strips: these draw power straight from the port and give a soft glow behind the screen, which looks best on a white wall.
• Presentation clickers: a cheap remote with a laser or on-screen pointer turns the TV into a slideshow screen for a home office or classroom.

Low-power novelty items, like USB fairy lights, generally run fine as well. If a gadget only needs electricity and no software, your TV can probably power it.

The rule of thumb is simple: if a device needs drivers, setup software or a PC to talk to, a TV can’t handle it. That rules out printers and scanners, and it rules out USB Wi-Fi adapters too.

Charging is another weak spot. In a pinch you can top up a phone from a TV port, but it will be very slow, and it isn’t a habit worth forming.

Webcams: the exception that depends on your model

Advice on webcams is split, and both sides are partly right. Older TVs don’t support them at all. Newer sets that run Android TV, Samsung’s Tizen or LG’s webOS can work with a USB webcam when paired with a video-calling app, which makes living-room calls or online fitness classes possible. A camera such as the Logitech C920x, which records full HD 1080p video, is a common pick. If your TV lacks support, a streaming box running Android TV is the usual workaround.

When a drive won’t show up, or shows up with no playable files, work through these causes in order.

1. Dirt or corrosion. Dust and oxide stop the metal contacts from touching. Unplug the TV, then gently clean the port and the plug with a cotton swab lightly dampened with isopropyl alcohol, and dry them.
2. The wrong format. Many older TVs only read drives formatted as FAT32 and ignore exFAT or NTFS. Back up the drive, reformat it to a system your manual lists, then copy the files back.
3. An unsupported codec. A TV may list a video file but refuse to play it because it doesn’t support the codec, the method used to compress the video. AV1, HEVC and WMV are common trouble spots. A free converter app can re-encode the file.
4. Not enough power. Ports differ, and external drives need more power than sticks. A drive that keeps connecting and disconnecting is a classic sign. Try another port, a drive with its own AC adapter, or a USB hub with a separate power supply.
5. Old or glitchy software. Unplug the TV for a few minutes to clear its cache, then check for a software update.

Size and file counts matter as well. Some older TVs only recognize drives up to 32 or 64GB, while newer ones read terabytes. Samsung TVs index up to 1,000 files in a single folder and 8,000 on the whole drive, so very large photo collections may show up only in part.

For most households, a smart TV USB port is a free media player, a power socket for lights and a way to make typing less painful. Before you buy any USB accessory for the TV, look up your model’s manual or the maker’s support page and search for its USB section. It will list the supported file systems, video formats and devices.

If you want a quick test, start with a small flash drive formatted to FAT32 and a common file like an MP4 video or MP3 song. If that plays, your port works, and you can move on to bigger drives and gadgets from there.