The Internet of Everyday Things Will Power Itself
by Steve Statler | Featured on Power Electronic News
You’d be forgiven if you assumed the Internet of Things (IoT) was just about communication. All those smart devices, smart buildings, appliances, cars, etc. communicating wirelessly all the time.
But that’s the Internet of Expensive Things, which includes about 11 billion connected devices, by some estimates. The Internet of Everyday Things will likely be a hundred times bigger—an Internet of Trillions. This IoT is all about by power: capturing and recycling the necessary power to communicate wirelessly anywhere at any time.
In this Internet of Trillions, packaged goods will communicate their location and condition; clothes communicate their origin and sustainability journey; and vaccines communicate information about their handling and viability. Similarly, a reusable transport item—a plastic pallet or a crate—becomes a remarkable data store, sensing its surroundings and communicating, for example, whether a shipment of fresh vegetables has been kept at a safe temperature and transported quickly enough to maintain freshness.
But how, when none of these everyday things is plugged into or powered by a traditional battery, can they communicate wirelessly via the internet? After all, everyone with a smartphone knows it takes battery power (and often, a backup charger).
Using innovative new technology, everyday things can communicate wirelessly by actually creating their own power. They do so by harvesting the wireless energy that’s all around us
The Best Energy Harvester is a Sophisticated Scavenger
Energy harvesting is nothing new, with solar power being one of the highest-profile examples. Solar works well for powering parking meters, but if we are going to bring online the packaging and containers that are at the heart of our supply chains—things that are indoors and stacked on top of each other—we need another solution.
The technology that gives everyday things like shipping crates both their intelligence and energy-harvesting power are small, inexpensive, stamp-sized computers, printed like stickers and affixed to crates, sweater labels, vials of vaccine, or other objects racing through the global supply chain. These sticker tags, called IoT Pixels, include an ARM processor, Bluetooth radio, sensors, and a security module—basically, a complete system on a chip (SoC).
All that’s left is to power this tiny SoC in the most efficient and economical way possible. It turns out, as wireless networks pervade our lives and radio frequency (RF) activity is everywhere, the prospect of recycling that RF activity into energy is the most practical and omni-present solution.
There are two primary paths for harvesting RF energy. First, by drawing steady energy from a wireless infrastructure that’s purpose-built to deliver it using radios that cost tens of dollars each. Possible, not practical. Or second, by “scavenging” energy from the radios in the devices that already surround us (phones, Wi-Fi access points, security cameras and smart speakers) and turning their communications transmissions into useable power.
It’s this energy scavenging paradigm that finally unlocks the Internet of Trillions and realizes all its benefits. The prospect of harvesting power without additional infrastructure makes an Internet of Trillions self-sustainable. Here’s how it works:
Harvesting Power for a Wave Computing Cycle
The ambient radio waves that surround us are typically not strong enough to power IoT devices if our intent is to use them for instant communications, but if we are willing to accumulate the energy in spurts as short as a few hundred milliseconds, we can collect enough over time to power a computing device. Imagine a bucket in a water park that becomes a mini reservoir by collecting small jets over time until it spills out a powerful wave.
Each IoT Pixel chip includes multiple harvesting units that transform even weak, bursty RF power emissions into DC voltage. Consider a shipping warehouse with a Wi-Fi network and multiple employees on wireless devices. Each burst of wireless communication creates RF energy that can be harvested by an IoT Pixel, including very weak signals as low as -30 decibel milliwatts (dBm). The harvesting units first use some of this energy to bootstrap and execute the programs burnt into ROM that govern the behavior of the device. Then they begin accumulating electrical energy in an internal capacitor to power the IoT Pixel’s SoC.
What does an IoT Pixel need to power? Essentially, two things. First, its operations. The SoC’s ARM processor needs to collect data from the tag’s sensors (such as temperature readings), prepare it for transmission, encrypt it, and tune the radio frequencies used so that when it sends the packet, that packet can be received and interpreted by other Bluetooth devices, including smartphones. Second, it needs to actually transmit the packet, which also takes power.
Unlike battery power, harvested RF energy is often only available in small bursts. The IoT Pixel knows how much power it has stored and how much it needs to complete the next stage in the process of preparing and sending its data packets. So, if it knows it will need to wait to harvest more energy, it stores its work in progress in an ultra-low power “retention” memory before finishing its operations and sending the packet on its way.
Wiliot engineers call this energy-compute-store process a wave computing cycle. It takes multiple cycles to transmit a packet. The IoT Pixel is designed to compare the power required to complete the next step in the computational process with the available energy and proceed only when there is enough energy to get to the next stage.
Plus, a wave computing cycle is energy efficient. The IoT Pixel itself consumes less than a microwatt (µW) of power and keeps its consumption low precisely because it’s not executing all its operations at the same time.
6G Will Accelerate the Progress
To be sure, scavenging RF energy to power an Internet of Everyday Things is by nature unpredictable. But the prospects of self-sustainability (battery-free self-sustainability, no less) are too great to pass up, especially when it comes to supporting a greener planet.
Looking ahead, future wireless standards, such as next generation 6G, are likely to include specifications for what the telco industry is calling “Massive IoT” to enable a world of leaner supply chains, traceability, and real-time inventory. Fortunately, solutions exist now.
Through an architecture that harvests existing RF energy, reduces power consumption to nanowatts, and communicates as the energy becomes available, engineers have created a platform where everything can be smart. In an Internet of Trillions, self-powered tags mean far greater supply chain efficiency, product safety, and traceability, without requiring expensive infrastructure. Companies around the world are taking advantage today. Many more will do so tomorrow.