The Nightmare of Ubiquitous Chargers

The Future, as seen by the 90s

Remember the future the way we imagined it back in the day? Where everything was magically all-knowing and connected – Your home detected when you returned and played your tunes, lit up the walls with your favorite art and warmed the house up just the way you like it. Your clothing was instrumented with all sorts of useful sensors and passed on this information to your home and computer. Your watch made measurements, and then talked to your shoes which called up your doctor’s shirt to exchange notes – I’m not sure what about.

Unfortunately, we aren’t there yet – not by a long shot – but why is that? Well, part of it is standardization of how these things talk to each other. But another important limitation? Keeping all these things charged. Wireless connectivity uses a lot of power so connected, portable devices just can’t last long without needing a charge.

Charging Ahead

Nest of Chargers

Nest of Chargers

I can barely manage to keep my cellphone charged everyday, not to mention my laptop, nook, cameras, etc. But a key theme of ubiquitous computing is that the technology should seamlessly integrate into your life and not demand attention. Any device that forces you to check and maintain it several times weekly, or even monthly, cannot be called seamless. The dream of ubiquitous computing has transformed into a nightmare of ubiquitous chargers and power bricks.

This maintenance adds a significant cognitive load to our daily lives, which essentially decides whether we buy a new gadget or not. In other words, it sets a threshold for ubiquity – devices must provide more perceived benefit than their cognitive or maintenance cost, or they won’t succeed.

Devices must provide more perceived benefit than their cognitive or maintenance cost, or they won’t succeed.

Cutting Loose

Bluetooth Low Energy

So, is there a solution? Thankfully, yes! There are a number of new low-power wireless technologies, such as Bluetooth Low Energy (BLE) and ANT, that are expected to be able to run off a coin cell battery for months, if not years, depending on the application. This means you may not have to charge this device or change the battery for its entire product lifetime!

Of course, these technologies are meant for low data bandwidth applications, like sensing devices and not for laptops and cell phones. But many small, low-power devices could easily talk to a local higher-powered device, and they would never need charging.

Standards, standards

And as for the other issue of standardization? While there have been other low-power wireless protocols in use already, BLE is standardized and included in Bluetooth 4.0. It  needs very little modification of older Bluetooth hardware to work. Already, the Apple IPhone 4S can communicate with BLE devices, and other phone manufacturers will likely follow suit as devices start showing up in the market.

Soon, a whole host of devices that would never have met the threshold of ubiquity before will become available, enabling a new wave of interconnected, low maintenance technology. So, are you excited? Your shoes certainly are.

[Disclaimer: I am currently doing an internship for Texas Instruments Low Power RF group, but I haven’t been paid to write this. On the contrary, I picked this internship because I am excited to learn more about these technologies.]


The best thing about Zebranet is the fact that it’s actually a network solution designed for zebras! Why do zebras need a network, you ask? Well, the network is actually for scientific researchers to study the migration patterns of wild zebras as well as their daily, social behavior.

Zebras by Chris Willis

Personally, I also love two specific aspects about this work, the first being that the researchers had to design for and work with real zebras in the wild and the second, that they got to travel to Kenya to do it.

The Design Challenge

The ZebraNet proejct from Princeton University had two major parts, designing a collar that zebras could wear that would collect information about their movement patterns and designing a peer-to-peer network protocol that would allow a large fraction of the data to return back to the researchers even if many of the zebras are out of the range of the receivers.

In addition, the receivers (or base stations) are not standing devices like cellular base stations. Instead, the researchers drive vehicles around the savanna to collect the data, hoping to get in range of a few zebras.

How it works

ZebraNet Project

ZebraNet Project

So how does this work? Essentially, the collars collect data on the movements of the zebras using GPS. They the forward this data to other zebra collars that have historically been successful at transferring data to the base station. Perhaps these zebras are the bravest of the bunch and venture furthest from the pack, zebras with a mind of their own. This protocol allows the data from the more conservative zebras to reach the researchers despite being out of range of the base station.

Another key factor is the requirement of a very long lifetime of the collars. Zebras can’t be counted on to charge the collars every night, so the collars have to be able to store all the required data and work for several months or more without intervention. To solve this issue, the collars recharge themselves using a solar array and then use that energy very efficiently. For more details, you can check out the NSF page, or this excellent article on the BBC.

Survival in the Wild

When I first read this paper, it was right on the heels of the big San Diego blackout, and I realized how useful it would be for cellphones to function in this way when power systems are interrupted. While many users lose all form of communication, some may have backup power and internet at their workplaces, or even a cellphone connection. Emergency text messages could relay through nearby users until they found a way to an actual base station, internet connection, or even the intended recipient. The message could include GPS tracking information if needed as well.

In emergency situations, this could be very useful at getting a message out to family saying you are okay or alternatively, that you need help. With the use of newer technologies like Bluetooth Low Energy, this could be done at very low power consumption, allowing your phone to work in emergency mode for a long time.

What do you think? Shouldn’t our phones be better equipped to help us during emergencies? What other applications could be helpful in emergency situations?