Joris Kluivers

I like to build software.

About Bluetooth Smart and iOS

In recent months products featuring the new Bluetooth 4.0 version started to become available (list). This new version introduces a new low energy technology that claims to save battery life, compared to traditional versions of Bluetooth. However due to the bad and confusing Bluetooth branding some confusion exists on what this means to the average phone or gadget user.

Terms like 4.0, Smart Ready and low energy (LE) seem to be applied at random to products. Users and even tech journalists often don’t understand what a product offers or what different Bluetooth labelling on a product exactly means.

Versions, technologies and compatibility

Bluetooth v4.0 is the latest version of the Bluetooth technology standard. It combines traditional versions (2.0 and up) and adds a new low energy technology to communicate with so called Smart devices. Low energy technology is not compatible with older variants and requires a new radio, but has the advantage of being very energy efficient.

To indicate compatibility the labels Smart and Smart Ready are introduced. Smart Ready devices (hosts) have a dual mode chip to communicate to both traditional devices and the newer smart devices. Smart devices (slaves) only have have a single radio and use LE technology exclusively. Smart devices only require a single button-cell battery for years of operation.

Somewhat confusing compatibility chart

Applied to iOS: The iPhone 4s is Bluetooth Smart Ready, able to communicate to both traditional Bluetooth 2 headsets and newer Bluetooth Smart devices like a heart rate monitor. Both the iPhone and the heart rate monitor devices use the low energy technology from Bluetooth 4.0.

While technically phones that use Bluetooth 4.0 are low energy capable, they often have a single chip that manages both the traditional and low energy bluetooth (and even the wifi). This means this won’t save battery life on a phone.

The chip in Bluetooth Smart devices (like heart rate monitors), that use the low energy technology exclusively is much more energy efficient. This makes these gadgeds last for years.

Available devices

For an overview of currently available devices (excluding phones / tablets) see the list of Bluetooth Smart gadgets I maintain.