The Zero Power Sensor Network is a solution for intelligent sensing, where sensing is wireless and passive. There are no batteries and no cables. Yet, the concept enables reading many sensors at the same time with communication distances of several tens of meters, high speed, high accuracy, and compliancy with the frequency regulations.
Within the scope of the Zero Power Sensor Network project, a complete system composed of a portable UHF reader and various passive sensors (accelerometer, inclinometer, strain, binary state) was implemented. Results show that reading distances of several tens of meters are achievable, with high measurement accuracy and compliance with the frequency regulations. The concept was extended to interrogate ten sensors at once (frequency division multiple access (FDMA)-concept), adding multi-functionality to the system. Recursive and thus computationally light estimation algorithms were developed to accurately obtain the sensor state. An integrated passive sensor tag was realized with the Integrated Passive Devices (IPD) process available at VTT. These results demonstrated that multiple sensors can be simultaneously interrogated across large distances and that the sensors can be manufactured in a highly integrated process, hence decreasing manufacturing costs.
- Long reading distances
- Wireless – no cabling
- Passive operation – no batteries
- Low cost sensors
- Multiple sensing with unique ID
- Compliant with frequency regulations
- Fast and accurate measurements
30 billion devices will be wirelessly connected by 2020. Fascinating and enabling thousands of new applications but nevertheless fully dependent on one source: power. Devices need power to communicate! Batteries, so far the main source of power, pose major issues:
- Batteries’ life expectancy is limited
- Battery-assisted devices can only be placed in accessible locations
- Batteries account for a huge amount of waste leaving a considerable footprint on the environment
Even though major efforts on energy harvesting development are on-going, new methods called for the development of wireless passive sensors.
The Zero Power Sensor concept will revolutionise wireless sensor networks: the market is gigantic as applications are everywhere:
- The Internet of Things: connecting cost-efficient sensors from anywhere and at any time
- Healthcare and well-being: wearable, lightweight, disposable and patient-oriented services
- Industrial Internet: machine life-cycle cost reduction, control and reliability towards the development of the Smart Factories of the future
- Smart and energy efficient buildings with embedded sensors in structures
- Environmental: reduced waste and lower energy consumption
Further development work will push the proof of concept research results into customer-oriented solutions.
Nadine Pesonen, VTT Technical Research Centre of Finland
VTT, Metso, KONE, Konecranes, ABB