Solving networked sensors’ energy problems
According to a study by the International Energy Agency in 2013, the energy requirements of all networked devices worldwide corresponded to the total demand for electrical energy in Germany. Within the next few years, this need will almost double to 1140 terawatts per year, with networked IoT accounting for a significant share of this growth. For this reason, it is important that sensors become more energy efficient.
So far, industry and research have not come up with a comprehensive solution: for each application, a single IoT hardware has been developed that is more or less energy efficient. The Fraunhofer-Gesellschaft wants to change with the “Towards Zero Power Electronics” (ZEPOWEL) lighthouse project. The research center will develop a hardware solution that is both holistic and extremely energy-efficient, ultimately aiming for complete self-sufficiency.
In order to succeed, the nodes themselves are to consume significantly less energy, and secondly, energy savings are to be achieved at the systemic level. This means that communication with other systems will also save energy.
“We want to create the technological platform for a comprehensive IoT application,” explains Erik Jung, project team member at the Fraunhofer Institute for Reliability and Microintegration IZM.
New technologies are being developed in the lighthouse project, such as an ultra-low-power wake-up receiver, which ensures that a sensor node does not have to transmit data continually, but rather “awakens” at a certain threshold or through an authenticated request from outside.
The module developed in the project is expected to be 1000 times more efficient than existing standard radio solutions. The receiver responds only to authorized and cryptographically secured signals that are actually relevant for it. In this way, the sensor node can remain in standby mode with minimal power consumption and be activated immediately by the WakeUp receiver as necessary.
In addition, the project is aiming at a unique sensor innovation: an air quality sensor is intended to be coupled with a micro-pump. The pump will then serve as a measuring amplifier by greatly increasing the amount of supplied air. If this attempt is successful, the result will be a sensor that can be built with much less intrinsic sensitivity, while at the same time providing data that is far more accurate. Whereas today’s sensors can deliver 5000 measurements at a power of 1250 microwatts per second, the developed sensor is expected to deliver twice as many readings per second with a power of less than 10 microwatts.
The sample sensor is intended to measure the particulate matter in cities. While measurements of particulate matter used to be extremely time-consuming and could therefore only be performed at a few nodes at the same time, the new technology is intended to enable a denser and more accurate measurement. The intelligent networking of the nodes and the connection to common cloud platforms can be used to create a detailed model of fine particulate emissions in cities. The applications are numerous: for example, traffic flow control could be based on it, and navigation systems could adapt their routes to it independently.
Also part of the project is the development of a broadband harvester, a kind of harvester for ambient energy. Its efficiency is to be quadrupled in comparison to the current state of the art: to harvest 100 microwatts of power from its environment, it will only need a quarter of the area, namely 5x5mm. The energy harvested in this way is to be stored in a newly developed thin-film battery, which will be integrated directly on the hardware chip. This fully integrated approach of battery, harvester and energy converter is unique in the world, claim the Fraunhofer researchers.
A modular construction kit for every application
The ZEPOWEL lighthouse project has also set itself the goal of not developing any purely application-specific nodes, but instead a modular approach based on the plug and play principle.
“We offer a module for many applications: it’s a plug-in system, like with Lego blocks. Click – and it works,” explains Erik Jung. The resulting platform consists of individual innovations created by the institutes which can be combined as desired. While a specific hardware solution has been created for each IoT application, a universal IoT hardware is being developed in this project. Depending on the application, the customer can then “cherry pick” as he prefers.
The Fraunhofer Research Institution for Microsystems and Solid State Technologies (EMFT) contributes its expertise in production-oriented microtechnology, innovative sensor solutions and microdosage to the project. In the project, the institute will develop a highly integrated gravimetric CMOS particle sensor consisting of low-noise analog signal processing, a multi-channel, high-performance analog-to-digital converter and subsequent digital signal processing. The system is complemented by a microactuator that allows on-demand media delivery. The actuators, driver electronics and sensors are used modularly as a system-in-package (SIP) in the IoT node.
Fraunhofer EMFT – www.emft.fraunhofer.de
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