Project Description

WISP Platform

The Wireless Identification and Sensing Platform (WISP), which is a programmable batteryfree sensing and computational platform designed to explore sensor-enhanced radio frequency identification (RFID) applications. WISP uses a 16-bit ultralow-power microcontroller to perform sensing and computation while exclusively operating from harvested RF energy. Sensors that have successfully been integrated into the WISP platform to date include temperature, ambient light, rectified voltage, and orientation. The microcontroller encodes measurements into an Electronic Product Code (EPC) Class 1 Generation 2 compliant ID and dynamically computes the required 16-bit cyclical redundancy checking (CRC). Finally, WISP emulates the EPC protocol to communicate the ID to the RFID reader. The WISP is the first fully programmable computing platform that can operate using power transmitted from a long-range (UHF) RFID reader and communicate arbitrary multibit data in a single response packet.

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Capacitive Touch Interface for Passive RFID Tags

This paper presents a novel method for incorporating a capacitive touch interface into existing passive RFID tag architectures without additional parts or changes to the manufacturing process. Our approach employs the tag’s antenna as a dual function element in which the antenna simultaneously acts as both a low-frequency capacitive fringing electric field sensor and also as an RF antenna. To demonstrate the feasibility of our approach, we have prototyped a passive UHF tag with capacitive sensing capability integrated into the antenna port using the WISP tag. Finally, we describe how this technology can be used for touch interfaces as well as other applications with the addition of a LED for user feedback.

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Localization of passive tags with integrated LEDs

The ability to accurately localize passive UHF RFID tags in uncontrolled and unstructured environments is limited by multi-path propagation. Therefore, in order to increase the spatial resolution of RF based localization methods we propose to combine them with additional sensing capabilities. In this work we enhance passive UHF RFID tags with LEDs, using the Wireless Identification and Sensing Platform (WISP). This allows both humans and computer systems (with cameras) to optically locate tagged items with millimeter accuracy. In order to show the effectiveness of this approach, a PR2 robot is equipped with an EPC Gen2 RFID reader and camera. Using the RFID reader alone, the PR2 is able to identify and coarsely locate tagged items in an unstructured environment. Once the robot has navigated to the vicinity of the LED-enhanced passive RFID tags, it uses the optical location method to precisely locate and autonomously grasp tagged items from a table.

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Photovoltaic enhanced UHF RFID tag antennas

The most significant barrier to improving passive RFID tag performance for both fixed function ID tags and enhanced RFID tags is the limitation on the amount of power that can be harvested for operation. This paper presents a novel approach for incorporating solar harvesting capability into existing passive RFID tags without increasing the parts count or changing the tag assembly process. Our approach employs the tag's antenna as a dual function element in which the antenna simultaneously harvests RF energy, communicates with the RFID reader, and harvests solar energy for auxiliary power. This is accomplished by using low cost, printable photovoltaics deposited on flexible substrate to form part of the antenna's radiating structure. Several prototype UHF RFID antennas are demonstrated using commercially available thin film, amorphous solar cells. To quantify the improvement in tag performance, Intel's WISP was used as an initial test vehicle. The effective read range of the tag was increased by six times and exceeded the reader's sensitivity limitations. Additionally, the new antenna allowed for sensing and computing operations to take place independent of the RFID reader under typical office lighting conditions.

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WISP Camera: Self-Localizing Battery-Free Cameras

In this work we propose using battery-free RFID sensor tags enhanced with on-board cameras to enable a network of distributed tags to optically determine the 3D location and pose of each camera tag given known reference tags enhanced with LEDs. Experimental results show that the camera tags are capable of determining their position with an average accuracy of [x, y, z] = [15.92cm, 4.39cm, 1.03cm] at an LEDs-to-Camera range within 3.6m.

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Videos

Open Source: The WISP Challenge

One of the key advantages of the WISP platform is that it’s PCB construction, fundamentally lowers the barrier to entry, allowing researchers to easily modify, hack, and experiment with RFID and wirelessly powered sensing and computing devices.It also became clear that a platform like the WISP had many more possible applications than we could possibly explore ourselves. Thus in 2008 we open-sourced the WISP 4.1 firmware and posted all the schematics and design files on the web. With a small investment from Intel Research we also launched the “WISP Challenge” were we solicited proposals from the academic community and ultimately donated over 500 WISPs to universities all over the world. Our aim was to seed the growth of a community of researchers interested in perpetually powered sensing and computing systems. Working with our WISP collaborators we organize the “WISP Summit” in conjunction with ACM SenSys 2009, to exchange information and see what sorts of results the community was generating.

All hardware and software files have been open-sourced and are available on the WISP Wiki

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Awards

Best Paper Award:"Capacitive Touch Interface for Passive RFID Tags"; IEEE International Conference on RFID, April 27-28, 2009

Best Demo Award: "RFID Sensor Networks with the Intel WISP"; ACM Conference on Embedded Networked Sensor Systems (Sensys 2008); Raleigh, North Carolina, November 7-8, 2008

Nominated for the Best Paper Award: "Sensor Enabled Wearable RFID Technology for Mitigating the Risk of Falls Near Beds"; IEEE International Conference on RFID; April 30 – May 2, 2013

Nominated for the Best Paper Award: "Optical localization of passive UHF RFID tags with integrated LEDs"; IEEE International Conference on RFID; April 3-5, 2012

Tech Transfer

In both academia and industry it is always great to see your research make it off the page, out of the lab, and into the real world. Often times this means handing off your favorite projects to other talented people who will carry them to the goal line. Here I am defining a Tech Transfer as an effort to commercialize one of my research projects that has become public.


BTAG

One of my final projects at Intel Labs, Seattle (formally called Intel Research, Seattle) was the development of a reference design for the BTAG (aka Brazil Tag). This was a stripped down version of the WISP 4.1, with an improved antenna, physical security features and a battery for longer read range. This is one of the first EPC Gen 2 tags that incorporated over the air AES encryption.

"Intel worked with the Brazilian tolling system operators and local manufacturers to develop an RFID tag (called BTag) exclusively for the country’s tolling needs. The project began at Intel Labs, Seattle, with extensive collaboration from the Intel team in Brazil, and was later productized. Intel worked with local industry to define and enable a local contract manufacturer and an Original Equipment Manufacturer, Autofind, to lead RFID and reader sales and implementations. To date, Autofind has sold more than 1 million BTags to the country’s main tolling operators." - Intel Case Study: Brazil Drives Into the Future - Intel Corporation, 2015

BTAG

Image source gigaom.com. This is one of my first BTAG prototypes that Terry showed off to the press back in 2012.


Related Publication

Related Projects

Thumb-NCF-WISP

NFC-WISP

The NFC-WISP is a wirelessly powered near-field RFID platform that is enhanced with onboard computing, sensing capabilities, and an E-ink display. This open-source platform is also compliant with NFC RFID readers commonly found in handheld devices and smart phones and offers designers and researchers a means to rapidly develop custom NFC applications.

3 Papers
2 Video
Open Source
Thumb-WISP 5.0

WISP 5.0

The WISP 5.0 is the second open-source release of the WISP platform and represents a significant improvement in both hardware and firmware architecture. Notable improvements include a revised RF harvester extending the WISPs operating range to ~9m, FRAM enabled MCU for lower power consumption and an new, and Energy-optimized firmware stack that supports more of the EPC Gen protocol. This project is led by Josh Smith from the Sensor Systems Lab at the University of Washington with Aaron Parks as the technical led.

Contributors

This project orginated at Intel Labs, Seattle (formally called Intel Research, Seattle) which has since closed. The WISP project has contiuned in Sensor Systems Lab led by Joshua Smith at the University of Washington.

For more on the History of the WISP Program, Josh Smith wrote an excellent summary as part of his book on Wirelessly Powered Sensor Networks and Computational RFID. While there were many people working on a variety of WISP related projects, I've listed the following collaborators that I had the good fortune of working with.