Diabetes is a debilitating disease, with approximately 366 million people worldwide. Its treatment today requires patients to take their own blood glucose measurements on a regular basis and draw blood by puncturing the skin. This is a painful process that is repeated and helps the patient suffer.

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How NFC Tag Sensor Device RF Technology Is Used?
Written By Calio Huang
Diabetes is a debilitating disease, with approximately 366 million people worldwide. Its
treatment today requires patients to take their own blood glucose measurements on a regular
basis and draw blood by puncturing the skin. This is a painful process that is repeated and helps
the patient suffer.
So, if it proves that radiofrequency technology can eliminate the need for a blood draw? Near
Field Communication (NFC) is a radio frequency protocol used to exchange data between devices
that are close or in contact (10 cm apart). Due to the support of the Android operating system on
smartphones and tablets, it is now widely adopted.
For example, medical device manufacturers are investigating the potential of implanting a
miniature NFC-type blood glucose sensor immediately under the skin of a diabetic patient. The
sensor can be read at any time, just by holding an Android phone or tablet and running an
implant next to a dedicated application.
The host device can automatically upload readings to the patient's doctor. It can also be
programmed to remind patients to read regularly and remind medical staff if the patient has not
taken the scheduled reading.
An NFC-enabled sensor is ideal for this application because:
It does not require an external power source because the sensor interface works on the energy
obtained from the rf emission input from the NFC reader.
It is fast and convenient because the sensors are immediate and automatic to the host device.
This is tiny
It is cheap
This example of implantable blood glucose measurement shows the promise of this new type of
NFC-enabled sensor-but in fact, this device type can be used in hundreds of applications in many
market sectors.

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The architecture of NFC-enabled sensor
An NFC-enabled sensor is an RFID tag that includes a sensor interface (for adjusting and digitizing
the sensor's input signal). Like other RFID tags, it has a unique ID, which allows users to verify the
origin of an object. However, it can also verify the environmental conditions to which the subject
is exposed, or provide other types of measurements, such as biological data from implanted
sensors.
Adding data acquired by the sensor to the tag does not change the basic method of
communication: when the tag is close to an RFID reader or an NFC-enabled phone with a
dedicated application, unique id and sensor data can be read.
Of course, there are other ways to implement wireless sensing. Today it is easy to connect a
sensor to an object and connect it to a microcontroller and rf transceiver to establish wireless
communication between a smart sensor and a reader.
Implementing this with NFC-enabled sensors provides simpler system design and a more flexible
approach to power management. In fact, for relatively low data rates and short-range
applications, NFC is a very attractive technology:
NFC enables intuitive and simple interaction between two devices because they only need to
touch each other.
Establishing an NFC link requires only a small fraction, while other systems typically take a few
seconds.
NFC has low power requirements, supports a very long battery life and achieves no battery at all.
The system cost of NFC applications is lower because the technology is not more complicated
than competing technologies for wireless sensings, such as ZigBee or Bluetooth.
Because NFC is coupled through the near field, it is not subject to eavesdropping and interference
NFC systems can rely on existing infrastructure-typically, system implementations only require the
creation of applications for host devices.
In the fully passive (passive) mode, the NFC-enabled sensor gets energy from the incoming RF
radiation power sensor interface and RF transmission. In the semi-passive (battery-assisted)
mode, NFC-enabled sensors can run independently in applications that require autonomous and
long-term monitoring. Alternatively, it can provide user-controlled on-board power to the sensor.
Feeling the marked life may include two modes of operation: semi-passive until the battery runs
out, and then passive mode. (Data is stored in non-volatile memory and retained when the
device is not powered).
Operation in a fully passive mode
A basic principle for the operation of RFID systems is that the tag gets all the energy to re-queries
the magnetic field generated by the reader. In an NFC-enabled sensor, this harvesting power
(usually about 4 mA at 3.3 V) can also be used for power sensors. Even if the energy obtained is
not enough for the sensor, for example, if the tag has a small antenna, or if it is a long distance
from the reader, a small supplementary power source of a capacitor can be added before the
measurement, and from it Extract power.
NFC-enabled sensors in a fully passive mode allow design engineers to show their imagination to
a new range of possibilities. The life cycle of a tag is theoretically infinite and it does not require a
wired connection. Therefore, these sensory tags can be embedded, for example, in internal

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structures such as walls and sealed products. As you can imagine, a builder is embedding a new
NFC-enabled humidity sensor on the wall or floor next to a water supply pipe or wastewater
drainage pipe. This will help detect today's leaks until they cause severe damage to the structure.
Semi-passive mode operation
Semi-passive tags include onboard power, usually batteries, to support tag and sensor operation.
Data transmission works in the same way as ordinary passive tags, using the backscattered power
emitted by the reader.
The user-controlled semi-passive sensory tag spends most of its time at rest, with the negligible
current drawn from the battery. The sensor functions and measurements are activated by the
user, usually when the device or the NFC device wakes up the rf transmission of the device.
Independent semi-passive tags used in independent long-term monitoring applications (so-called
data loggers) can be activated by external events or triggered by an integrated real-time clock
(RTC). Such applications will require a continuous current of typically 2µ from the battery to
support RTC or event-triggered wakeups. This condition for monitoring NFC sensor tags can be
installed on items that require special care during transportation. At the end of the supply chain,
an NFC-enabled reader device checks sensory tags and issues an alert when an alert occurs
during unauthorized shipment. In addition, the sensor data is time-stamped, allowing detailed
event monitoring.
Image of NFC-enabled sensor
NFC-aware implementation
Therefore, NFC-based sensing applications require energy harvesting capabilities, sensor
interfaces, power management circuits, and real-time clock (RTC). These features are now
available in sl13a NFC Transponder MCU to feel from AMS. The chip complies with the NFC-v
(ISO15693) standard and integrates an on-board temperature sensor.
Sensory tags work in fully passive and semi-passive modes; when on-chip RTC is needed, the
battery is used to support autonomous data recording. In passive mode, a reader or NFC-enabled
phone replaces the timestamp, and the energy that supports the sensor operation is taken from
the field of the reader.
The recorded sensor data is stored in on-chip EEPROM and protected with a password to prevent
data manipulation and unauthorized use.
NFC block diagram for sl13a enables sensors from AMS
sl13a can support a very wide range of applications and sensor data collection requirements for
wireless data transmission. These measures include:
A reminder with shelf life-supply chain under conditions of transportation and storage of goods,
as well as environmental conditions, can be monitored and recorded sl13a. Perishable items such
as food, beverages, and drugs are subject to temperature-dependent chemical reactions, which
determines their shelf life. Some sensory tags include algorithms that dynamically calculate shelf
life and provide alerts on expiration dates.
Building monitoring-sl13a and appropriate embedded sensors in structures such as buildings,
bridges, and viaducts record conditions including temperature, humidity, pressure, vibration, and
triggering an NFC reader when transmitting data. Medication-Integrated sensory tags for
dispensing and blister packs can record and time stamp the consumption of pills. This enables

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medical staff to monitor patients for compliance with their prescriptions.
Process control-In factory automation, sensory tags control the process and it is quality at every
step of the process. This is more effective than the final quality assurance of the finished product.
Remote metering-sl13a sensory tags can be integrated into the device's wireless connection, such
as WLAN, GSM, the ability to extend tracking and monitoring of objects or environments at
remote locations.
Implementing a mature communication protocol that provides accurate and precise sensor
interfaces, sl13a demonstrates new possibilities for integrating multiple electronic functions into
a single device. However, the widespread use of this flexible device has yet to be discovered-the
imagination of system designers will provide the best guidance for the potential use of this new
sensory RFID tag.