An accidental article talking about Bluetooth & the iWatch

Listening to the latest episode of the Accidental Tech Podcast today the topic of Apple's speculated "iWatch™" featured when talking about a recent Apple hire. One thing that was mentioned is that it is not clear how this would "work" with an iOS device stating that 'Bluetooth probably has something to do with it'. Bluetooth certainly has something to do with it and theres some interesting hints to go along with that.

Over the past 6 months I have been playing and experimenting with Apple's Core Bluetooth framework. It utilises the new Low Energy Bluetooth medium to be able to talk to external peripherals. This is already used in products by FitBit, Nike, BlueHR and many others which are primarily focussed around health & fitness monitoring.

However, Low Energy Bluetooth can do so much more than that and over the past couple of iOS releases has been hinting at the possibilities that Apple may be exploring in the future.

So here is what I have been thinking about over the past few months with all of the iWatch™ speculation. First, just an overview of what I'm talking about then into the finer details and hints over the past few years.



What is Low Energy Bluetooth capable of?

Here is Bluetooth's key features for its low energy technology:

  • Ultra-low peak, average and idle mode power consumption
  • Ability to run for years on standard, coin-cell batteries
  • Low cost
  • Multi-vendor interoperability
  • Enhanced range

Its a rather simple concept. Low Energy Bluetooth is designed to be basic in what it can deliver but in turn gain so much in energy efficiency. Primarily designed to send small, structured data and not stream large blobs.

As an example, a device as big as a 50¢ coin could be placed on a shelf and periodically advertise the current ambient room temperature for over a year, on one CR2032 battery. Requiring no "pairing", just scan for temperature sensors and the current temperature can be read automatically by another device.

With that said; it is capable of more than a couple of bytes of data. It is feasible and within its capability to transfer data that represents a contact card or a very small file - requiring some chunking to get it over in manageable pieces.

A lot of the technical detail has been glossed over but that hopefully should give a rough idea of how it is different to Classic Bluetooth and other technologies.


Hints over time

October 2011

The beginning of this story starts with the release of the iPhone 4S which shipped as the first mass-produced consumer Bluetooth Smart (4.0) device. At the time there was no Core Bluetooth framework. Moreover, this was not a hint as to Apple's ideas on making a wrist device however it did outline Apple's direction in adopting Bluetooth and its low energy capabilities.

Then in iOS 5 the Core Bluetooth API was revealed allowing developers access to talk to external peripherals in a simple and managed manner without worrying about energy consumption or getting MFi approval. However, the framework was quite basic, with no documentation and had its faults. It did not do much more than allow an application to talk to another device and didn't expose any system notifications.

April 2012

An interesting side story is that during Pebble's Kickstarter campaign there was no way that they could have gotten the notification information they needed for the watch with current API's. At that time they were looking like they would have to join the MFi programme which requires extra technology, Apple's blessing and get access to some very private APIs. Maybe they had inside info that what they needed, MAP support, was not far in the pipeline or just timed it perfectly.

September 2012

iOS 6 added much needed documentation and the MAP support that Pebble needed. This kick started the accessibility of Bluetooth on iOS and peripherals began to pop up. Early adopting fitness and health fanatics started exploring early peripherals focussed on tracking their fitness and sharing it with all of us on Twitter.

June 2013

We arrive at the recent release of the iOS 7 beta which more than ever cements Apple's choice for Bluetooth over technologies like NFC. But it revealed the much needed services for a wrist bound product:

  • Alert Notification Service
  • Apple Notification Service Centre
  • Current Time Service

These new services are available on all iOS 7 devices, with Bluetooth 4.0 (not the iPhone 4), by default and are managed by the OS.



The new iOS 7 services in detail

Going into individual detail about these services points out what each one achieves and how it can help build a wrist bound device.


An absolutely obvious requirement for a wrist device is the Current Time Service which allows a "dumb" or Internet-challenged device the ability to sync their clocks with a connected service without themselves being directly connected to the Internet or timekeeping service. No need to manually set the time or even adjust it for DST changes or travel either, your primary timekeeping and connected device will do that for you.


Apple chose to create their own notification service as they found the standardised Alert Notification Service lacking in capability and extensibility with iOS' wide spectrum of alert types and information. Although ANS has values "reserved for future use" it is too basic and generic to be able to handle Push Notifications for specific applications and display rich data.

If the idea of a wrist mounted device is to reduce the need to look at a larger format device in a pocket then having accommodating notifications with rich data displayed is key.

The Message Access Profile (MAP) available on Classic Bluetooth doesn't have the low energy benefits that are necessary for a device with limited volume for batteries.



What does it all mean? 

A smart wrist device needs a couple of things to live up to our basic expectations: timekeeping and notifications.

Both of these basic features are there in iOS 7 ready to be utilised. But its not just Apple that can use these services, any future wrist device made by any company can access these services. Not only is this a starting block for Apple but its a call to anyone that wants to make something to get started.

Even if we don't get the magical, revolutionary and stunning iWatch™ that has been speculated it won't be long before someone else makes it for us.

That's what I love about Low Energy Bluetooth, the GATT profile and its availability in iOS. It no longer requires the co-operation with Apple to be able to talk to third party peripherals and its all done with a technology that is open for any other device to use as well. 

Connect the world.