The secret payload of the iPhone 4S: Bluetooth 4.0

People have paid a lot of attention to two new features that arrived in the iPhone 4S(s aapl): The much-improved camera and Siri, the new voice-powered digital assistant. But the 4S also snuck in another feature upgrade, one that’s a ticking time bomb of potential goodness: Bluetooth 4.0. The tech is also present in Apple’s most recent Mac mini and MacBook Air releases.

What is Bluetooth 4.0?

It’s the latest incarnation of Bluetooth, the wireless device-to-device technology that allows your phone to talk to headsets, car stereos, keyboards and other devices directly, without the need for a router or shared wireless network. The 4.0 version of the specification (also called Bluetooth Smart) introduces greatly lowered power consumption, thanks to a new way of maintaining a connection between devices without the need for a constant stream of data being transferred between the two.

Bluetooth 4.0 also contains the high-speed data-transfer specifications that were introduced with Bluetooth 3.0, which allows for speeds of up to 25 Mbps. The latest spec is backward-compatible with previous versions, so your iPhone 4S will still work with the Bluetooth 2.0 stereo headset you have, for instance, or with your Apple Wireless Keyboard.

What can Bluetooth 4.0 do for you?

Thus far, not much. Bluetooth 4.0 requires both sending and receiving devices to have the technology on board before it can really start showing benefits for users. As mentioned above, it works fine with devices using older versions of the spec, but it doesn’t get to take advantage of any of its power-saving features with Bluetooth 3.0 or lower.

The big benefit of Bluetooth 4.0 will come from peripherals, much like with Thunderbolt(s intc) technology. Unlike with Thunderbolt tech, however, consumers can expect Bluetooth 4.0 accessories to launch with price ranges and use cases that are much more palatable to the average consumer. Thunderbolt, like FireWire before it, will at first be a cost-prohibitive high-speed data-transfer tech aimed at film and video pros; Bluetooth 4.0 plants the seed for a wide range of more-consumer-oriented applications.

Input, input, input

Bluetooth 4.0 will be most useful for the new crop of sensor devices coming to market that aim to provide your iPhone or computer with a wealth of external data to help inform special applications. Perfect examples of how the tech might be used include heart rate monitors, GPS sensors and environmentally aware devices, somewhat like the new Nest thermostat.

Such peripherals will be able to be powered much more efficiently than those using previous Bluetooth standards, which will make their promise of being set-and-forget devices more of an attainable reality. Bluetooth 4.0 peripherals powered by simple watch batteries will be able to collect and inform specialized applications on iPhones and other devices, allowing for a smarter and more integral connection between our lives and our devices.

One example of where Bluetooth 4.0 could come in handy is with the smart watch technology that Kevin Tofel has been following so closely. Theoretically, a smart watch using Bluetooth 4.0 would be able to get much more out of limited battery life than existing devices, allowing for a long-lasting connection that doesn’t require much attention from a user. Imagine the battery life of your current quartz wrist watch but with the ability to deliver notifications when your phone receives a text or call.

Whole-home devices

Bluetooth 4.0 paves the way for a future in which your MacBook Air, Mac mini or iPhone can passively monitor and keep abreast of everything going on in your house. Monitor the temperature of that roast you’re cooking, note when your solar array stops receiving direct sunlight, and have your cordless robot vacuum tell you when it needs to hit the charging station: All could be possible through future implementations of a low-power, direct-communication spec like Bluetooth 4.0.

That’s the long-term play that Apple has made with the 4S. Nice to see users get something that could pay dividends much further in the life of their product, rather than just another limitation that becomes a reason to upgrade in a year’s time.