The Qualcomm Toq

The smartwatch battery problem

One of the biggest obstacles to smart watch adoption is poor battery life. But the industry is working on improving longevity.

The smartwatch has been seen as ‘the next big thing’ in consumer tech for several years. In fact, a number of devices have already been launched by LG, Sony and Kickstarter company Pebble. In September, Samsung launched the Galaxy Gear at Berlin’s IFA consumer technology trade show.Market intelligence firm ABI Research predicts more than 1.2 million smartwatches will be shipped in 2013. However,traditional watch sales have declined in recent years as its basic functionality, keeping time, can be carried out by all mobile devices. Therefore, an entire generation has now grown up looking at their phone displays to tell time.

There is one advantage, however, that an ordinary watch has over any smart gadget - you don’t have to worry about the battery draining in a couple of days, or even hours. Limited functionality offers this advantage. Therefore, while the consumer electronics industry looks to develop the functionality of watches, it has to tread very carefully to ensure that any increased functionality does not reduce battery life.

“The strong potential emergence of smartwatches can be attributed to several reasons,” says ABI Research’s senior analyst, Joshua Flood. “Contributing factors include the high penetration of smartphones in many world markets, the wide availability and low cost of MEMS sensors, energy efficient connectivity technologies such as Bluetooth 4.0, and a flourishing app ecosystem.”

The wearable computing device can be split into four categories: notification types, voice-operational smartwatches, hybrid smartwatches, and completely independent smartwatches. Notification type devices are the MetaWatch and Cookoo smartwatches, for example, offering alerts for incoming calls, messages and other notifications. Voice-operational smartwatches enable users to conduct calls and speak certain commands via the device.

Better power management

Improved efficiency of software and hardware in mobile devices has always been an issue for the consumer electronics industry. Therefore, the big consumer tech companies and chip makers are always striving to improve power management.

The manufacturers at Pebble claim that their smartwatch lasts for seven days with light use - although this kind of claim is rarely matched in real-world scenarios. However, tests by reviewers have claimed that it does generally last for more than three days.

The Pebble smartwatch uses power management modules from STMicroelectronics. Its STM32 microcontroller, the brain behind the watch, is an ARM-based processor which has been optimised to work at very low power levels - something that is easily accomplished as the watch has not been designed to require complex or powerful processing.

“Pebble wearers want a watch that connects seamlessly to their devices and can run for days so they can enjoy all the benefits of their smartwatch without worrying about performance or battery life. The STM32 F2 makes that possible,” says Eric Migicovsky, Pebble’s founder and CEO.

In addition to the STM32 microcontroller, Pebble also features a digital-output motion sensor produced by the same company. The LIS3DH senses acceleration along all three axes and uses low-power operational modes that allow advanced power saving and smart embedded functions.

Pebble has taken the view to discard everything that would possibly be superfluous in a watch. This means no colour screen and no camera. The company’s vision is that the smartwatch would primarily be a notification station on your wrist - a second screen to your ‘smarter’ phone.

Samsung, on the other hand, has decided to put some real heft in its offering. It has a larger colour display, metal construction and a camera. All of this, however, leads to a shorter battery life. For real power users, you’ll have to be certain to be near a power outlet and have your battery charged at least once every 48 hours.

The screen is where companies are looking for better power management. One company, E-Ink, has been producing low-powered displays for e-readers, such as the Kindle, for many years.

Currently, the refresh rate is only about one-eighth of a second and full-colour screens have been elusive. The company does produce a colour version, but the quality is considerably lower compared to modern LCD and AMOLED screens. E-ink can work on a flexible substrate and requires only a tiny battery.

“This market is still evolving,” says Giovanni Mancini, E-Ink’s director of product management. “The question is, how many people really want a smartwatch that’s a full smartphone?”

Other display technologies are also becoming increasingly efficient. OLEDs are flexible and offer vibrant displays, and a number of high-end smartphones now use this technology.

Another technology is Qualcomm’s Mirasol, which uses tiny MEMS-based mirrors to refract ambient light and produce different colours. The technology has already been introduced in the company’s recently released Toq smartwatch prototype.

Advanced battery technology

Mobile phone batteries pack such a punch that they can be used to jump-start a dead car battery according to William King, professor of mechanical science and engineering at the University of Illinois. But this is still not enough to power a smartwatch for several weeks.

Professor King has led a group that claims to have developed the most powerful microbatteries ever documented. According to research published in Nature Communications in April of this year, these microbatteries beat even the best supercapacitors and could drive new applications, including smartwatches.

“This is a whole new way to think about batteries,” Prof King claims. “A battery can deliver far more power than anybody ever thought. In recent decades, electronics have shrunk. The thinking parts of computers have shrunk. And the battery has lagged far behind. This is a microtechnology that could change all of that. Now the power source is as high-performance as the rest of it.”

For applications that need a lot of energy - for prolonged periods of listening to music, for instance - fuel cells and batteries can hold a lot of energy but release it or recharge slowly. Thus, watchmakers would not have to worry about recharging for weeks or possibly even months.

The new microbatteries offer both power and energy. By tweaking the structure, the researchers can tune them over a wide range on the power-versus-energy scale. They have power densities up to 7.4mW/cm2/μm.

The batteries owe their high performance to their internal three-dimensional microstructure. Batteries have two key components: the anode (minus side) and cathode (plus side). Building on a fast-charging cathode design, Prof King’s group developed a matching anode as well as a new way to integrate the two components at the microscale to make a complete battery with markedly superior performance under laboratory conditions.

With so much power, the batteries could enable sensors on devices 30 times smaller. The batteries are rechargeable and can charge 1,000 times faster than competing technologies

The researchers are working on integrating their batteries with other electronics components, as well as focusing on manufacturability at low cost.

Communicating between devices

Most of the smartwatch designs imagine that the main processing will still be done by the smartphone, using the larger real estate and functionality that already exists. As the smartwatch will work in tandem with an existing smartphone, a great deal of thought has to be put into wireless networking capabilities.

Bluetooth appears to be the obvious solution, but ‘classic’ Bluetooth was developed as a standard for the PC era using protocols from the 1970s such as RS232 interface. Not terribly efficient.

A more suitable technology is required for smartwatches. Over the last few years, the Bluetooth Special Interest Group has been working on another version of Bluetooth called ‘Bluetooth Smart’.

This technology started life as a home automation wireless protocol developed by Nokia called Wibree. As such, it was designed to be power efficient and was optimised to send simple commands rather than audio or data files, which is a major function of classic Bluetooth. Steve Hegenderfer is development director for the Bluetooth SIG. He believes that, with an improved software stack on smartwatches and companion smartphone devices - where both devices are low-power Smart Bluetooth-enabled, battery performance could increase by the magnitude.

“With improved software development, it would be possible to have smartwatches running for months without needing to be charged,” claims Hegenderfer. “There’s no reason why smartwatches could not run off a standard coin cell battery. I think it’s a possibility.”

According to analyst firms ABI Research and ON World, Bluetooth Smart device shipments are expected to reach more than one billion units per annum in the next five years - a five-fold increase since the autumn of 2012.

iSuppli further notes that, using Bluetooth Smart technology’s low-power, low-cost, and ubiquitous wireless technology, billions of physical objects gather, communicate, and make use of information to advance and bring efficiency to our infrastructures, services and lives.

According to Hegenderfer, Bluetooth Smart is on its way to becoming the de facto standard. A growing number of manufacturers select it as the wireless connection for hooking up wearable activity monitors and smartwatches with other devices that may comprise the body area network - anything that can be connected via a common network. Devices that this might consist of include smart glasses (such as Google Glass), heart rate monitors, medical sensors and so on.

The big players

But what of the behemoths Apple and Google, who have transformed the mobile phone sector in the last few years? These companies are working on smartwatch technology and have been for quite some time, if reports are to be believed.

Could it be that the lack of a long battery life may have prevented them from launching anything to date?

Google Now functionality is reportedly at the centre of Google’s product and, if used, would enable the user to link their watch to their smartphone. Information such as calendar alarms, emails and text messages could all be pushed to the watch’s display.

Google Now, an intelligent personal assistant developed by Google, is available within the Google Search mobile application for the Android and iOS operating systems. It includes a natural language user interface to answer questions, make recommendations, and perform actions by delegating requests to a set of Web services. Along with answering user-initiated queries, Google Now passively delivers information to the user which it predicts they will want, based on their search habits.

Apple is rumoured to have been working on its ‘iWatch’ smartwatch for a while now, but the company is accelerating work on the project as it tries to expand its family of mobile devices to the wrist. Apple has already started work on trademarking the name in a number of countries.

Most likely, the iWatch will serve as an accessory to the iPhone and other iOS devices, giving users easy at-a-glance access to common functions without having to take their larger devices out of their pockets or bags. It should also incorporate a number of its own sensors and software features to help stand on its own as a must-have device for users. Rumours have also suggested that the iWatch could serve as a control device for home automation.

Initial chatter indicated that the iWatch could launch as soon as the end of 2013, but it now looks like a debut in the second half of 2014 is more likely.

Not much in the way of specific detail about the iWatch has surfaced since the project apparently remains in the early stages, but reports say that the watch will include a 1.5in display and run a “full” version of iOS.

Sensors and biometrics should also play a key role with the iWatch, perhaps including pedometer and heart rate monitor functions. The iWatch should also integrate with the iPhone and other iOS devices, allowing users to check caller ID, place calls, and access maps as an accessory to the larger devices.

But there is very little about power management. Certainly, however, power management was an important selling point for the iPad when Steve Jobs launched it in 2010. The pinnacle of the launch keynote was when Jobs announced that he had watched movies on a trans-pacific flight to San Francisco lasting 10 hours without plugging the device in. *

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