The illustration above describes challenges facing practical autonomous mobile robotic solutions. Original is apparently by Rodney Brooks – the Bad Boy of Robotics – shown to first year students of artificial intelligence. Given it’s audience, the illustration makes it point vividly: no matter how fancy AI you develop, there are more mundane problems you need to solve first, before you can make anything useful.
I’ve worked in a mobile software business for 6 years now. Before that I studied autonomous mobile robots for a while. Surprisingly autonomous mobile robots and mobile phones have more than one thing in common. Both have sensors – cameras, accelometers, compasses, you name it. And both are supposed to do useful things even when you are not keeping eye on them. But one property is of a special interest here:
They are both mobile and thus wireless.
And why is this interesting? Because currently there’s no practical solutions to charge batteries without a wire, remotely over the air.
Both robots and mobile phones run out of juice over extended period of use unless charged. Under heavy use current crema de la creme of mobile phones are guaranteed to emit their last desperate beep just before you were about to call your special one to inform that you are late from the anniversary dinner.
Better battery life
I’ve seen a good share of mobile phone user surveys in my past. Most of them have a section where people were asked either what they want to improve in the current model they had or what kind of device would be their ideal phone. These surveys are in many ways of limited value, but they give you some understanding what kind of things users appreciate. In every survey I encountered, a modest request for “better battery life” hit Top-3.
Mobile phones have become an integral part of our modern lives. They are our main and one of the most intimate communication medium. They have replaced alarm clocks in our bed rooms. Many use them as daily cameras and notebooks. The more adventurous of us are already relying their navigation abilities on these little devices.
Running out of battery is becoming as paralyzing as running out of gas in the middle of nowhere.
The suckers
Who then is sucking the life out of our batteries? The main culprits are network usage, bright big displays, GPS location fixes and heavy computing. Most of the mobile applications are not computationally heavy, so displays and using sensors like GPS for a longer period of time constitute a significant power drain.
However, in coming era of connected apps, the network usage will be the main culprit. The power consumption of network usage is especially bad when it happens periodically even with small amounts of data. For each request, a phone’s radio changes itself from an idle, low power consumption state to higher power usage state to enable 3G data traffic. This is very common pattern of network usage, for example it happens every time your email or chat application polls for new messages. For this exact reason, Apple is trying to create a user controllable and understandable shared model of notifications for iPhone.
Some people have succinctly expressed that all these extra bells and whistles are causing the poor battery performance. And they are right. But I bet that in five years time, teens won’t hesitate to wonder “How could you ever survive without maps in mobile phones?” or “You facebooked from a desktop? Your life must have SUCKED!”. Being able to find your way or communicate with your friends easily are instruments of high value.
The solutions
There are 3 ways to deal with the battery problem:
- make longer lasting batteries
- consume less battery
- charge more often
Making longer lasting batteries
Just make batteries that last longer, right? You can bet that people have tried, but it’s one of the technologies where the basic laws of physics prevent fast progress. Batteries are quite simple technology and there’s not that much you can do to improve them. There is progress, but it’s of an incremental nature. And we are much faster at inventing new useful things that consume power.
Consuming less battery
There are two ways to try to consume less battery: a hardware way and a software way.
Instead of making ever more powerful processors, innovators try to make processors that do a bit less, but with a lot less of power. Transmeta, a company doing exactly that, was made famous overnight in 90s by a fellow Finn, Linus Torvalds, by a mere act of joining them. I haven’t heard much about them lately. I hope they were overrun by competition, not drought of ideas.
On the network side, things are not looking pretty. 3G is a battery sucker, and there’s no light at the end of the tunnel, because 4G networks seem to be even worse. Even if the battery problem would be aggressively approached by network manufacturers, lead times of network deployment are in order of 10 years.
The software approach is to make software more clever, so that it consumes less battery. Nokia has provided instructions on how to make energy efficient applications and also provides an energy profiler tool for S60 phones. Apple is taking another approach by limiting capabilities of applications – applications can’t run on background – and providing a common shared push notification model.
Mobile phones are most of the time in your pocket, you use them in 4-10 second bursts. The concept of background processing is essential for many mobile innovations. Applications on Android will provide more seamless experience compare to iPhone just because of the background processing and I think Apple has to deal with that somehow.
A problem is that even if you know how your application consumes power, there’s not necessarily much you can do about it. You can reduce your polling frequency, but eventually this will render your chat application useless. Current network APIs don’t provide ways to lower a quality of service for better battery life.
Charge more often
As two other ways of dealing with the battery problem are not going to provide any short term solutions, I’ve been thinking about the third way: how to make users charge their phone more often.
It’s a very interesting user interaction design problem. Charging is something no one really wants to do. It isn’t anybody’s goal to charge a phone battery. On the other hand battery power is a critical resource for many daily activities. It’s like money. If we make it easy for people to ensure that they have enough battery life to do tasks they need to do and enjoy their mobile life, they can appreciate this and avoid frustrating moments. Even if it takes some effort from a user.
One solution is what I call accidental charging. You connect a phone to a wire for a totally different reason than charging and charging happens as a side effect. A prime example of this is iPhone. To sync your music, calendar events and contacts, you need to connect it to your computer. While iTunes is syncing, your phone is being charged. Other great example is small iPod docks in audio systems: you connect your iPod to a dock to play music from it, and as a side effect, it’s charged.
The second approach is related to the accidental charging, I call it physical affordances. Palm hand-helds and some older phone models used to have a separate charging stand. Some people frowned upon them and saw them as unnecessary, ugly things. However, those stands, located on your bedroom table or next to your desktop, were visually inviting you to put your phone to a charger. They reminded you about the fact that your phone is not charging by their empty presence.
Why not provide charging stands that are truly beautiful design objects that you can keep visible in your home and at work? Couple them with some useful functionality – syncing, playing music, showing photos in a photo frame – to enable also accidental charging.
Third, improve users mental model of power consumption. As battery power is a valuable resource for users, it’s important to get the mental model right so that user can make educated decisions how and when to save battery. Running a simple chat application might appear innocent compared to a capturing of a video.
My Nokia E65 has 7 power bars. When phone reaches 4 bars, I have no idea how long can I safely web surf with it, because those last bars always seem to go too quickly. Either visualization is not linear, or I’ve bad mental model how much surfing consumes the power. If I have a bad mental model of the useful battery life, I just wonder how people who have never seen power measurement graphs in their life can map those 7 bars to useful battery life. One way to improve mental model could be to visualize the current power consumption with some simple animation or colors on battery indicator. People would learn to understand that certain applications consumes a lot of power and it’s better to be avoided, when you want to save your last 2 bars for important calls. Without extended usability testing, I can’t say if this really a good idea or not. But in a way or another mobile phone industry have to educate users to get their mental models of power consumption right.
Fourth approach is smarter battery notifications. Don’t you just hate that running-out-of-battery beep? It always come too late and in the middle of important call. Why don’t phone suggest charging when I’m 50% way done? Of course it would be annoying if phone beeps when I’m at that anniversary dinner. But phone knows where you are by cell towers, wifi stations, Bluetooth devices and GPS location. It could easily detect your daily patterns as most of us have very predictable lives. Home. Work. Somewhere else. Home. The phone could remind you to plug your phone to a charger, if you forget to do it when you come home.
And why it needs to make irritating sound to remind me of charging? Retro geeks can keep their beeps, I want my phone to imitate Reginald Jeeves: “If you would charge your phone, sir. It helps you to get through a busy day tomorrow.”
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