Can Energy Harvesting Power Wearables, Internet of Things?
Powering devices with energy harvested from ambient sources can create illusion of magic, says Intel researcher.
Smart watches, highway sensors, sleep-tracking wristbands and smart city systems all have one thing common: they need power. Harvesting energy to power these small, always-on devices presents a daunting challenge, but solving it holds magic potential, according to an Intel researcher.
"I think solving the power problem will create the illusion of magical devices," said Alanson Sample, a research scientist in Intel Labs who is working on energy harvesting. "If the user never has to go in, recharge it and it has wireless communication, they don't have to interact with the device for it to work. You don't even have to be aware that it exists. All of a sudden you have these magical experiences."
Research on energy harvesting points to some ways to make those magical experiences possible. Energy can be harvested from any ambient source in the environment - power is all around us. As an example, Sample points to the electrical potential created from sap running through tree veins. Yet, potential doesn't always mean practical.
"There's lots of energy out there. The question is what's useful," Sample said.
Of the potential sources for harvesting energy, solar is the most mature at this point. Vibration, radio frequency and temperature also hold promise - already sensors are being deployed in industrial settings that harvest energy from temperature differentials, such as those between hot and cold water pipes.
To demonstrate possible functionality within a tight power budget, Sample and his fellow researchers developed a smart employee badge that uses solar and RF energy to power sensors, an accelerometer, E Ink display and other features.
Sample and his colleagues are also looking beyond those established power sources to harvesting energy off the human body. The hurdle there is that while kinetic motion generates energy, it's highly variable. The 5-10 microwatts that could be harvested from a sitting person might leap to 500 microwatts when he or she walks or runs.
"If I have an energy source that varies all the time, I have to create systems that can take advantage of that power source," said Sample. "I can't say that I want to do this amount of computational load every single time because I don't know if I'll have the power for that."
Taking advantage of that variability requires a paradigm shift that defines functionality by power budget rather than the other way around. That means developing devices that are somewhat reptilian, according to Sample.
"Some of the devices that I create are kind of like cold-blooded animals - when it's cold they don't move, when it's warm, they do," he said. "When a device doesn't have much power, it may only be able to send a packet once every couple seconds, but when there's more power it has more functionality; maybe it can tell you location, temperature, velocity or even stream audio or video. It's all dependent on how much power it has."
In considering the potential for wearable electronics, Sample returns to the element of magic.
"There are two important pieces," he said. "First, creating the illusion that there are no electronics - making it truly invisible from the user's point of view. And, second, making devices that last forever. After you solve the power problem, it really comes down to how long the part is going to last.