Détection NFC: une nouvelle dimension des applications et services NFC

[Version anglaise uniquement]

NFC offers much more than just well known NFC applications like ticketing, tagging and payment. The future and great value of NFC in health care and ambient assisted living as well as other industrial areas lies in simple and fast sensing of parameters which are relevant for health care or lifestyle scenarios and marketing activities. This article provides an overview on the basics of NFC sensing, the required technology and use cases as well as a real world application.

Manfred Bammer - AIT
Gernot Schmid - AIT
By Manfred Bammer,
AIT Austrian Institute of Technology GmbH
and Gernot Schmid,
Seibersdorf Laboratories GmbH

Totally unknown just a few years ago, Near Field Communication (NFC) is now increasingly establishing itself as one of the most promising forward-looking technologies for wireless data exchange over short distances. Its communication design is remarkably simple and manufacturers are increasingly integrating NFC technology into smartphones and electronic devices. This means that the usability and availability of this technology are virtually unlimited. It is also compatible with RFID infrastructures operating in the 13.56 MHz frequency band. Many applications for cashless payments, ticketing, marketing, and in the health care and nursing sectors will therefore be made possible by this communication technology in future if not already in place.

Why do we think that NFC is best suited for AAL and Healthcare applications as well as for lifestyle and marketing scenarios?

The answer is quite simple, because NFC technology is very easy to use! Just touch a NFC enabled smart card to start an application via an e.g. App on a smartphone and then follow the visual or audio guide by just touching other NFC enabled devices and information or symbol tags. A further important advantage of NFC is that, for most applications, only one communication point or NFC enabled device has to be active, i.e., only one of the two communicating peers require a power supply (battery). Therefore, NFC covers a lot of further aspects like energy harvesting, green technology, ultra-low radiation, smart integration and makes a lot of new applications ready for the mass market. Finally, with NFC the internet of things can be realized quite easily.

What is the idea behind NFC Sensing? A promising approach for the application of NFC in healthcare is the combination of the simple handling of NFC with different sensor functionalities. By an advanced design of the NFC-antenna and the surrounding hard- and software, the intelligent NFC-tag can operate as a smart sensor with NFC-interface for the transfer of measurement data. With this principle, various sensor applications for health care or lifestyle scenarios can be realized. In this article two developments of NFC-sensor applications from AIT and Seibersdorf Laboratories are introduced like NFC based fill level measurement and NFC based ultraviolet (UV) assessment for sun burn prevention. The main advantages of these applications are that all NFC-sensors can simply be used by medical, nursing staff or patients and consumers.

NFC-based fill level measurement

Self-injection technologies have been growing continuously since the 1980‘s in many fields of medicine. They enable many patients with chronic diseases a convenient self-treatment. Although pens and auto-injectors for administering insulin for diabetes patients are currently the most known and widest used products, many other diseases are treated using self-injection devices too, e.g. psoriasis, cancer, osteoporosis, multiple sclerosis as well as treatment of impaired growth. Usually, such a pen consists of a dosing and injections mechanics in the upper part and a holder for a replaceable cartridge („injectable“) which contains the drug to be injected.

Due to cost reasons, most pens and auto-injectors are purely mechanical, i.e. they do not contain any electronics, which consequently means that recording about the administered dosage needs to be done manually by the patient, based on a paper/pencil principle (diary). Moreover, the remaining fill level of the cartridge can only be obtained by visual inspection of the rather coarse and imprecise scale on the pen or by calculating from the diary recordings. Especially in case of elderly, mentally and/or visually impaired patients, irregularities (e.g. forgotten entries) in the diary recordings can therefore lead to problems with dosing which can have serious health impacts. Therefore, a cost efficient and reliable system for the determination of the cartridge fill level is highly desirable. The trend to disposable pens is worldwide very high, so that the requirements for a cheap housing including a fill level measurement system are even higher than for reusable pens.

NFC as a highly intuitive, modern and reliable short range communication technology in combination with a passive capacitive fill level sensor system, was found to be a very promising approach to address the above mentioned requirements, as described as follows.

With an intelligent design of measurement electrodes, NFC antenna and shielding (protected by several patents), capacitive sensing of the fill level in a cartridge can be realized. This concept is very flexible and the measurement electrodes can easily be realized by a vapour deposit, printing process or a label on the outer surface of the cartridge.

In addition, a resonant 13.56 MHz communication antenna is packed on top of the measurement unit and connected to an advanced low power NFC-compatible transponder chip (currently under development), containing, in addition to the RF-interface and CPU, two 13.56 MHz analog signal inputs, and A/D converters for processing the voltages induced in the measurement unit. The supply power of the entire transponder electronics and sensor circuit can be harvested from the 13.56 MHz magnetic field of the reader device, i.e. a NFC-enabled smart phone with a corresponding software application (Fig. 1).

Figure 1 - Fill level measurement of an insulin cartridge

Figure 1: Fill level measurement of an insulin cartridge in a self-injection pen by a NFC-enabled smart phone using the newly developed system

All the electronics required in the transponder can be operated purely passive (i.e., no battery inside the pen is required) and can be realized at low cost in a size that can easily be integrated in the shaft of the pen without significantly altering its dimensions and/or design.

The described innovative system provides highly beneficial features for patients using self-injection systems. Beside precise cartridge fill level measurements with an accuracy of up to 0.5 insulin units (corresponding to 5 microliter, automated dosage recordings, dosage calculators, reminder functions and direct wireless data transfer to health telemonitoring systems are only a few examples of possible future applications enabled by this innovation.

NFC-based ultraviolet assessment sensor

Overexposure to ultraviolet (UV) radiation induces photochemical damage of skin cells (causing the commonly well-known sun burn) and is presently seen as the most frequent cause of skin cancer. Presently available personal UV-monitors are battery powered stand-alone devices. These are expensive because they need to contain all required components (sensor diodes, signal processing, measurement control, post-processing of the measurement results, etc.). The development described here shifts the sensor front-end and the minimum required ultra-low power electronic circuitry into a slim low-cost and passive smart NFC transponder. All other required steps are carried out by the corresponding App on the user’s smart phone, thereby creating a robust, low-cost and reliable personal UV monitoring device for the mass market. The system consists of a simple, robust and slim low-cost UV-sensor integrated into a smart transponder (e.g., in smart card format). The measured raw data are transferred to the smart phone with corresponding App via NFC. In order to keep the sensor small and low-cost a broadband photodiode overlaid with an appropriate UV-filter is used for the measurements (figure 13). The cutback of the broadband measurement, i.e. that the measured UV intensity does not contain any spectral information, can be compensated by the App on the smart phone, based on actual GPS- and time data as well as data obtainable from global UV-radiation databases (locally stored on the phone or via real time access). Based on additionally available personal data (skin type, sun tan lotion, etc.) the individual maximum exposure time can be estimated. In summary, this device therefore brings both a health benefit for the end user as well as an added value for cosmetic industries.

Figure 2 - Basic outline of the NFC-based UV assessment

Figure 2: Basic outline of the NFC-based UV assessment. Top: schematic block diagram; bottom: outline of smart transponder and usage in practice

Future perspectives of NFC for Sensing

In healthcare, the systems for data capturing of vital patient data have to be easy to use, reliable and fast. In healthcare scenarios you always have the need to measure biosignals but also to ask the patient for other information such as wellbeing, pill intake, physical activities, bread units and much more depending on the disease. In the need of a technology which can measure or capture all this data, NFC is the only technology where electronically measured values and non-electronic information can be captured with the same protocol and device.

One of the features of NFC making it especially suited for healthcare applications and usage by technically poorly skilled or impaired persons is, that the communication is started by just bringing the two peers close to each other, i.e. no additional action for initiating the data exchange by the user is necessary. Taking into account that NFC is already being integrated in more and more mobile phones, and the high penetration of mobile phones in the population, NFC offers the possibility for a wide variety of useful applications not only in healthcare and care applications but in many areas.

In short, with NFC sensing, more valuable and easy to use applications are possible at reasonable costs than with other wireless communication technologies!

Dipl.-Ing. Manfred Bammer, MAS, Head of Biomedical Systems, Department Health & Environment, AIT Austrian Institute of Technology GmbH
Manfred Bammer joined the AIT Austrian Institute of Technology in 1993, where he is head of the Business Unit Biomedical Systems and inventor as well as creator of the project “Next Generation NFC Applications”, which is a co-operation between the AIT Austrian Institute of Technology and the Seibersdorf Laboratories. In parallel, Manfred Bammer is the safety officer for medical device development of AIT.  Manfred Bammer has authored or co-authored more than 20 conference and technical papers in the fields of NFC (Near Field Communication) and is inventor of more than 10 NFC patents pending.

Dipl.-Ing. Gernot Schmid, Senior Applied Researcher, Project Manager and Deputy Head, Seibersdorf Laboratories GmbH
He has been working on numerous national as well as international research projects related to the exposure assessment in electromagnetic fields, the biological impact of electromagnetic fields, and electromagnetic interference of medical implants. Moreover, since 2009 he is involved in the development of NFC sensor applications. Gernot Schmid is member of the expert group on EMF of the Austrian Federal Ministry of Health. He is author/co-author of more than 20 refereed articles in SCI-listed journals, more than 100 conference papers, numerous research project reports and inventor of more than 10 NFC-related patents. 

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