Last year, computer engineers at Northwestern University and Delft University of Technology (TU Delft) introduced the world’s first battery-free Game Boy, which harvests both solar energy and the user’s kinetic energy from pressing the buttons to power unlimited gaming life.
The same team now introduces a new platform that allows novice manufacturers, hobbyists, and programmers to build their own battery-free electronic devices that run on intermittently harvested energy.
Called BFree, the system includes power harvesting hardware (the BFree Shield) and a power failure resistant version of Python, one of the most accessible and most used programming languages. All the user needs is a basic understanding of Python to quickly and easily transform any DIY smart device into a battery-free version. With this technology, novice programmers can now turn their DIY battery-powered motion sensor, for example, into a solar-powered sensor with infinite lifespan.
The research will be presented virtually at 11:00 EDT (USA) on Wednesday 22 September at UbiComp 2021, the premier conference for ubiquitous computing. Users can find instructions on how to build and use the new technology here.
‘Asking the wrong question’
“Right now, it is virtually impossible for hobbyists to develop devices with battery-free hardware, so we wanted to democratize our battery-free platform,” said Josiah Hester of Northwestern, who co-directed the work. “Manufacturers all over the Internet are asking how to extend the battery life of their devices. They are asking the wrong question. We want them to forget about the battery and instead think about more sustainable ways to generate energy ”.
“The manufacturing community is generally more interested in rapidly deploying their devices, and that speed doesn’t always go well with sustainability,” said Przemyslaw Pawelczak of TU Delft, who co-directed the work with Hester. “We wanted to design a good product that could connect these two worlds.”
Hester is an assistant professor of electrical and computer engineering and computer science at Northwestern’s McCormick School of Engineering. He is also Allen K. and Johnnie Cordell Breed Junior Professor of Design. Pawelczak is an assistant professor at the Embedded and Network Systems Group at TU Delft, where he heads the Sustainable Systems Laboratory. Their team includes Ph.D. candidates Vito Kortbeek, Abu Bakar and Stefany Cruz.
The Maker Movement Battery Problem
An extension focused on DIY culture technology, the Maker Movement encompasses a diverse group of computer inventors, designers, and programmers who build their own hardware and software for electronic devices, including motion sensors, displays, actuators, and more still. Combined with cloud computing, the ability to develop fast, cheap and connected devices enables the Internet of Things (IoT). These DIYers make everything from home automation devices to weather stations and everything in between.
While the growing number of people capable of building and programming devices presents an exciting future for technology, Hester, Pawelczak and their team are put off by the number of batteries that will be used and eventually end up in landfills.
“Many people are predicting that we will have a trillion devices in this IoT,” said Hester. “That means a trillion dead batteries or 100 million people replacing a dead battery every few minutes. This represents a terrible ecological cost to the environment. What we’re doing, on the other hand, is really empowering people. We want everyone to be able to effortlessly program devices in a more sustainable way. “
‘Invisible’ to the user
But simply giving up on a battery isn’t as simple as it might seem. When devices bypass the battery and instead rely on energy harvesting, the power is no longer constant. If the sun is hiding behind a cloud, for example, solar energy could be temporarily interrupted.
With BFree, the researchers solved this problem. The technology allows devices to run perpetually with intermittent energy. When the power is turned off, BFree stops the calculations. When power is restored, it automatically picks up where it left off without losing memory or having to perform a long list of operations before restarting. Not only does this save energy, but the technology is also more user-friendly than traditional programs, which lose all memory of what happened immediately before a power failure and have to be restarted from the beginning.
To make the process easy to use, the researchers coded BFree with software to interpret Python programs for batteryless devices. A user only needs to connect BFree Shield to the Adafruit Metro M0 build platform (or slightly modify it to work with other CircuitPython based platforms) and then program the device as it normally would. The BFree software takes care of the rest, allowing the program to run without batteries, exclusively from the energy collected, and to run perpetually in the event of a power failure.
“We wanted to make it totally invisible to the end user,” said Kortbeek, who has a Ph. candidate in Pawelczak’s group. “So, we tried to keep the original device experience intact without the user seeing how we modified the software to interpret Python files for battery-free technology.”
“Now everyone can build and program smart and sustainable devices,” said Hester. “This makes the future vision of ubiquitous computing more sustainable, useful and environmentally responsible.”