In Defense Of Infrared On Smartphones


Following Samsung’s launch of the Galaxy Note 10.1 with its updated hardware, we took a little time last week to dwell on the inclusion of an infrared port. Our Joe Levi talked about Samsung’s plans for it, and reflected a bit on the glory days (if you could call them that) of IrDA, but didn’t seem entirely won-over by Samsung’s decision. Me, on the other hand: I’m a huge infrared fan, and would love to see more of it out there. What makes infrared so great?

Joe hit the nail right on the head with some of the reasons infrared was once so popular, including low power consumption. That’s a big deal, especially as we demand more and more from our phones’ batteries, but it’s just part of IR’s appeal.

All the Bluetooth in our phones, all the WiFi, and all the NFC are radio-based technologies, and as a result can be a pain to implement. Manufacturers need to design phone hardware with RF emissions in mind, carefully engineering and positioning individual antennas to maximize their efficiency. With IR, it’s a whole lot simpler: all you need is some free space on the edge of the handset for an IR-transparent window, an LED, and a photodetector.

IR isn’t just easier to design around, as it also makes device approval simpler. All those RF systems need to have their output ratings filed with the FCC in the US, or equivalent agencies abroad. IR, operating just outside the visible spectrum but still very much a type of light, isn’t encumbered by similar legal red tape.

Altogether, factors like these can make IR much cheaper to implement than RF-based systems. When we’re dealing with smartphones themselves, that’s not such a big deal, as they contribute just small fractions to a device’s final price tag, but for accessories, the things our phones talk to over these interfaces, the impact can be larger.

OK, but just what kind of accessories would really use IR? Smart watches seem like a good start. Sure, they’ll still want RF systems so they can receive info from our phones when not in direct line-of-sight, but they could take advantage of IR in other ways. What about something like in-store announcements? IR beacons in the ceiling could strobe news about the latest deals, or updated info about store closings, to any IR-enabled devices in the vicinity, including both smart watches and smartphones themselves. That kind of broadcast messaging isn’t easy to do well with current RF-based systems.

What about remote controls? This also feels like the most pedestrian use of IR, but I still think it’s arguably the most important. Infrared-based remote controls for home electronics aren’t going away anytime soon; even as we see more and more “connected” devices, IR’s still going to be available, and unless we update all of our hardware to those new standards, we’ll still need IR to fall back on; I don’t think anyone’s going to be releasing a web-connected LaserDisc player anytime soon.

I played around with the idea of using a WinMo PDA as a universal remote last decade, and while I didn’t have much success with the hardware available to me, it was clear that this had the potential to be a great use of the technology. Unless you go really high-end with your universal remote, the kind of device that’s practically a smartphone itself, you stand to lose quite a bit of functionality. The remotes that comes with high-end electronics can be riddled with dozens upon dozens of buttons, and unless your universal remote is the size of a small book, it’s not likely to feature all the same inputs.

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The trick to doing it right is having really flexible hardware. IR remotes can send their signals by any of a number of protocols and at different speeds, so the receiver hardware for a good universal remote – or in this case, our smartphone or tablet – needs to be able to read and reproduce all those varying signals. Get that hardware right, and have the sort of flexible software that can easily reproduce the input options for even a complicated remote, and you’ve got the recipe for one very versatile control system.

Then, there’s just the tinkerer in me who absolutely loves having as many varied inputs and outputs available on my gear as possible. In my dreams, smartphones would have a BeBox’s worth of interfaces (in addition to a ton of normal I/O, the BeBox was wired for THREE separate infrared ports). While I’m not holding my breath for such luxuries on modern hardware, infrared alone could open up some new doors. You’ve probably played with a cheap radio-controlled toy helicopter that worked over IR; with a quick app, and a phone with decent IR hardware, you’d be able to control a whole fleet right from your phone.

Obviously, IR isn’t going to be the most widely used feature, and it definitely has its limitations, but it’s cheap and easy to implement, has a lot of potential, and can help bridge modern and vintage hardware. What I want to know is, why wouldn’t you want one more connectivity option for your phone?

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About The Author
Stephen Schenck
Stephen has been writing about electronics since 2008, which only serves to frustrate him that he waited so long to combine his love of gadgets and his degree in writing. In his spare time, he collects console and arcade game hardware, is a motorcycle enthusiast, and enjoys trapping blue crabs. Stephen's first mobile device was a 624 MHz Dell Axim X30, which he's convinced is still a viable platform. Stephen longs for a market where phones are sold independently of service, and bandwidth is cheap and plentiful; he's not holding his breath. In the meantime, he devours smartphone news and tries to sort out the juicy bits Read more about Stephen Schenck!