 Hello, my name is John Tran. I am an application engineer supporting SDNFC and RFID products. First I'd like to thank you for attending this webinar. Today we are going to talk about NFC Sensor Tag. The NFC Sensor Tag is an NFC-enabled sensor node that can register environmental data. Our objective was to build a reference design that is scalable with temperature, humidity, pressure. Vibration and motion sensor can be added based on the final product requirements. At the same time, we need low power, low cost, compactness, and utilizes the simplicity of NFC communication. What is NFC? NFC stands for Near Field Communication. In the wireless spectrum that most of us are familiar with, NFC is a near field wireless technology with low data rate. It centers around 12.56 MHz versus the typical Wi-Fi and Bluetooth targeting 2.4 GHz. It is zero power for the client device as the reader provides inductive power through its magnetic field. In many applications, NFC is used to complement Wi-Fi and Bluetooth technology where pairing data is exchanged in near field so that the payload cannot be sniffed. In the sensor tag, NFC is used mainly to communicate and transfer data. The NFC data follows the standards that was created by the NFC Forum, a collection of companies that manufacture products that use NFC chips or manufacturers of NFC chips such as ST-microelectronics. The specifications cover all supporting protocols such as ISO 14443AB and ISO 15693. Upon those protocols, NFC Forum creates methods of data exchanges and data formats themselves. This is where NFC data exchange format comes into play. The tag communicates to the reader by switching its load from low to high and vice versa, and the reader can detect this change. This process is also known as load modulation. On the other hand, the reader changes its carrier frequency via either amplitude or phase shift, and the tag can decode this signal modulation. In addition, as we had discussed, the reader also produces the RF field that would power the tag. So in near field, it can be considered that the transfer of energy will be done like a transformer. The major difference is that the magnetic field inside the iron core of the transformer is much stronger and energy transfer is practically lossless. For NFC, the transfer of energy is over free air and therefore is not as efficient. So in summary, the reader and his respective antenna will act as the primary of the transformer and send energy to the secondary that will be the sensor tag. Our current sensor tag design includes accelerometer, barometer, humidity and temperature sensor. There is also a corn cell battery holder so that the sensor data can be logged over time. There are three modes in which the tag can operate. No battery or fully passive. In this mode, the tag is fully powered by the NFC reader RF field. It can relay sensor information as long as the RF field is present. The second mode is non-rechargeable battery. In this mode, the tag logs sensor data at a configurable interval. And then the final, the third mode is rechargeable battery. In this case, the NFC magnetic field can be used to recharge the onboard battery so that it can be used over and over again. Once again, the tag needs to be in the RF field for energy harvesting to occur. Let's look at the sensor tag at the schematics level. In battery or data logging mode, VDD or power is being regulated by the 1.8 volt low drop voltage regulator. In the default configuration, R11 is populated. It's not populated. And the sensor group is consisted of an accelerometer, barometer, humidity and temperature sensor. And this group is powered by the 32-bit microcontroller SCM32L0 by GPIO pin. One can also depopulate the R10 shunt, removing the R10 resistors and connect the R11 resistors. In this case, the sensor group will be powered directly by the voltage regulator. This is the flexibility in power configuration that is presently available on the evaluation board. Furthermore, the accelerometer and barometer can wake up the microcontroller when a certain sensor event has been triggered. Notice that this is not available on the relative humidity and temperature sensor, only the barometer and accelerometers in this configuration. Besides powering the SD25DV NFC dynamic tag IC directly, the microcontroller can also put the SD25DV in a low-power mode, consuming less than one microgram by driving the LPD signal high. The GPIO signal alerts the microcontroller when an RF field or nearby or RF commands are being sent. The SCM32 microcontroller communicates with the sensor group via SPI bus. On the other hand, it communicates with the SD25DV using I2C bus. The NFC sensor tag utilizes SD technology in connectivity, computing, sensing, power management, and discrete. In connectivity, we SD microelectronic offer Bluetooth, NFC, Wi-Fi, LoRa, and sub-gigahertz. But in this application, we are going to use NFC. In computing, we have a whole range of microcontrollers. But due to low-power requirements and cost sensitivity, we're going to use the SCM32 L011. Actually, in this design, it is using a L031, but we could possibly use the lowest version, the L011, if a more cost-reduced version would be used with less sensor cores. In sensing, our MEMS sensor portfolio, COVID gyroscope magnetometers, accelerometers, barometers, humidity, and temperature sensors. And in this design, we are using accelerometers, the LIS, to the W12, and pressure temperature, the LTS-22HB, and humidity and temperature, the HTS-221. We are also a leader in power management, particularly low-drop linear regulators. And SC also deliver a rich portfolio of discrete devices such as diodes and rectifier. So in general, all the silicon on the ST NFC sensor tag, evaluation board, has all ST technology. Now, let's look into NFC. Our NFC product group has the name ST25. It includes all the important elements needed for a rich NFC ecosystem. Beside products such as ST25 DV dynamic NFC tag, ST supplies also as NFC RFID readers and standard NFC RFID tags. Also, ST produced secure NFC devices such as secure elements and NFC controllers for mobile phone, for example. And these products belong to a different group and not under the ST25 umbrella. Typically, NFC tags store static data and that can only be updated via RFID system that comprises microcontroller and NFC transceivers such as the ST25R. So in this chart, you can see EM vehicle readers are used for mobile payment. The automotive readers are used to perform various tasks inside cars. And general-purpose readers are used to connect to your PC and they're used for all sort of reading and writing to standard tags. And in focus of this design, we use the NFC dynamic tag. Now, the NFC dynamic tag can communicate with microcontroller such as SCM32 via I2C bus. So this opened a wealth of possibility applications such as industrial, consumers, metering, appliances, Internet of Things, can relay information at the EM microcontroller level to the outside world via NFC. And as NFC is gaining ubiquity on the mobile phone platforms, we now have a simple and unique data port to get system information using the dynamic tag. So within our ST25 product portfolio, you can notice that we have the ST25 tagged ICs covering ISO 14443A, ISO 14443B, and ISO 15693. And their memory can range from 2K bit to 64K bit. The dynamic tag finally covers ISO 14443A and ISO 15693. And notably the ISO 15693 device, the ST25DV, is being used in our NFC sensor tag. And for HF transceiver IC, we make CR95HF, ST95HF, ST25R3911, or more or less the 3900 sub-families. And we also produce UHF retransceiver IC. Let's look at the ST25 dynamic tag in detail. So looking at the M24SR following ISO 14443A protocol with speed at 106K bit per second and with a connection I2C to 1MHz. The M24LR is an older product, now more or less superseded by the ST25DV. And particularly the ST25DV has a 256-byte buffer for fast data transfer and also C4 bit password and faster I2C bus. Furthermore, the ST25DV allows fast RF access up to 53K bit per second to its 256-byte buffer. This is done via a special RF command, such as fast read message and fast write message. There's also a particular read block, fast read block, and fast write block. Several packages are available ranging from the ubiquitous SO8 to silicon wafer chip scale package. The 12 pin package allows access to LPD pin, which we had discussed earlier on the schematic level, where we can lower the ST25DV power to the low 1 microamp. So the application for NFC dynamic tag is vast. Just because we add that extra port, the I2C port, we now are able to do all sort of things. For example, inline customization product can be configured on the factory floor as it be going out to the customer or being configured. And it can also be configured at the point of distribution as well. You can store ID but product specific information. And the customer can retrieve it using NFC phone. And this is crucial for warranty purposes and information. And it can also provide information to the field technician. And it can be dinos simply using something like a web application, a cloud-based application that determine what is wrong with the hardware. NFC dynamic tag can also be used to secure Bluetooth and Wi-Fi pairing as we discussed earlier. NFC dynamic tag can also be used to commission new hardware such as LED lights or security cameras to put them on a mesh network of sort. We can use our power in full passive mode to power smart sensing application such as the NFC sensor tag. And of course, you can also firmware upgrade in some application where data of the firmware is rather small. And sometimes the power configuration is small enough that you can actually power the entire tag with its associated microcontroller and update the firmware. Do you know that there are 700 variants of SEM32 microcontrollers? And there are many of them supporting Cortex M0 Plus and Cortex M4. For the NFC sensor tag, we chose the SEM32 L031. This particular SEM32 has 31 kb of flash for code, 8 kb of RAM for variables and buffers and 1 kb of EEPROM for non-volta data storage. The ultra-low power architectures, both a 250 nanoamp standby current consumption. The microcontroller core can operate up to 32 MHz using either external crystals or internal RC oscillators. SD produces leading sensors that cover accelerometer, gyroscopes and magnetometer, pressure, humidity, temperature and MEMS microphone. These products come with low power consumption, thermal stability and precision. In our sensor tag, we put three sensors, the LIS-DW12, come in tiny 2x2 x 7mm package. This accelerometer has a selectable full scale of 248 or 16G with 12 to 14 bit resolution. The device consumes 40 nanoamp in standby and it also has a low power mode that consumes 380 nanoamp. The LPS-22HP is suitable for weather station, indoor and outdoor navigation, performing as both a barometer and altimeters. This device has a range of 260 to 1260 hectopascals. Accuracy is about 10 microbar and 6 cm resolution. It has a low power consumption of 3 microamp. And finally, the HTS-221 is a relative humidity and temperature combo sensor. The device has a range of minus 40°C and plus 125°C with half of the degree accuracy from 15°C to 40°C. So why an NFC-enabled sensor node? Well, low cost comes to mind, ultra low power, easy to implement, flexibility and enhanced text features which comes with NFC, so it's an added value. Let's talk about low cost mean. So low cost comparison with technologies such as Bluetooth and Wi-Fi. Since NFC does not require expensive chips antenna, in many cases the antenna can be a simple coil or PCB trace on the board. While an FCC verification is needed as it is an unintentional radiator, the process is not as expensive and complex as certification. Low power, full passive mode. In this full passive mode, the NFC sensor tags get all the power from the NFC reader magnetic field. This implementation does not need a battery, obviously. And it's also not a data logging feature because it only gives you the data at the instant the reader field is there. Because once you're taking the reader field away, the system no longer has power so it cannot truly data log. So in that application, it's more or less getting real-time logging or a sanity check of an environment, not so much for logging over time. In the low power mode, there will be needed a power source, like a battery for example. However, the tag would be sleeping most of the time and it will wake up at interval, whatever it is, one second interval or one hour interval to collect data and then store inside the SD25 DV memory. And therefore, in some cases, it can drain the battery but it can be very power saving if set correctly. So in the consumption profile, as you can see in the active mode, the SCM32 can use up to 245 microam and the LED would consume 150 microam on this particular board. But if it didn't stand by mode or mostly sleeping, it consumed very little power. And because you're using the SCM32 as a 32-bit microcontroller and a fast I2C bus, you can actually shorten the time in which you get the data, store it and go back to sleep. The shorter the time you can do it, the better is the power saving. Looking at the consumption profile, as you can see as the time interval lengthens from one second to one hour, the consumption in current diminishes drastically. And in the low case, in every one hour, you can consume almost very little amount and so very little stress on the battery itself. And of course, this will be configurable based on the type of application, the type of use of the sensor tag. When you need to collect data every one second for maybe a few days or you collect every hour for a period of few months. Here we're looking at the battery life profile and as you can see, if your interval is one hour, it could last years. But if you are using one second interval, the time drastically drops down. But in application, when product being shipped across a region, for example, when the time being transported is only a few days, you don't need to worry so much about over a long period of time. So another thing that we want to look at is easy implementation. The implementation for NFC antenna is very simple. Sometime it's just a small loop, inductive loop, and therefore it can be built within the PC board itself. In case of the NFC sensor tag is basically all around the circuit board and inside is all the components needed for the sensor tag. 15.56 mega inductive antenna is much simpler than 2.4 gigahertz PCB antenna. There is no special PCB layout technique to deal with. And also NFC driver from a firmware perspective is much more compact in quite less code space than Bluetooth stack or Wi-Fi stack. And that means that it leads to a cheaper solution, right? And it's less requirement of flash memory on the microcontroller. The NFC tag is absolutely scalable. Need only a shock detector or recorder? Simply remove the other two sensors and modify the firmware to accommodate that change. If another sensor is desired, start from the layout of the current board and add the needed sensor. And add the sensor driver in the existing library and add some code to accommodate the new sensors. Beware of the fine of power footprint as it would impact operation in full passive mode. Beside being a great data logger, the NFC sensor tag also has special features. One can use the 256 bytes buffer in the SC25DV to actually upgrade the firmware inside the SCM32L0. Since the implementation is via NFC, an UID or unique identifier is available to differentiate one sensor tag from the other. And this UID is read only by nature and it can never be overwritten. So in summary, low cost in comparison with other wireless technology such as Bluetooth and Wi-Fi. Low power which translates to longer battery life and also possibility of battery less operation due to NFC. Easy implementation and easy certification. Only a verification with FCC is required. Flexibility and scalability for any application. The ability to add and remove different sensors and NFC provides added features such as UID and firmware upgrade. In most cases, asset tracking only involve logging environmental data of goods during transit. For example, code change management ensures that perishable goods maintains its quality during transport. In that a breach of humidity and temperature can damage the product and ultimately the brand itself. So the NFC sensor tag has a great ability to monitor goods from manufacturing to end user. The sensor tag can also be implemented into building structures to measure leaning tilt and degradation of a long period of time. It can measure vibrations that ultimately can cause damage to the structure. A weather station can also be implemented. It can be located anywhere in the city where anyone can tap with a phone and get humidity, temperature, barometric information. Connect the unconnected using the phone NFC capability and animated things can relay crucial information to the user. Has the humidity reached the medicine bottle? How hot is that baby bottle? Is the bottle of the wine perfectly chill? These are questions that can be quickly answered by the NFC sensor tag. NFC sensor can also be built into flexible patch like a small band-aid that relays customer vital signs that can be checked with a tap on the phone. For example, a patient can be sleeping wearing a special band-aid. Basically a band-aid that can measure temperatures, skin temperatures, skin humidity and perhaps a possibility of heart rate monitor. A notice can walk up to the sleeping patient and tap with the phone, recording all the data, registering the data log information. And that information can be analyzed using a web application without disturbing the patient. No need for attaching loads of wires and complicated machine. An NFC sensor tag can be made in form of a patch or band-aid fixed to an athlete, for example, to measure her skin bio-sign during an extreme workout. And she can determine if she needs to be hydrated due to those data with a tap of an NFC phone. Is it important to guarantee quality of pressure or good as they are being transported to their final destination? The NFC sensor tag can log all the needed information that ensure quality and protect the brand. NFC sensor tag can be implemented into smart packages. It can determine if the luggage has been opened and how many times it has been opened. Or that the luggage has been subjected to high-level damaging shocks. NFC sensor tag can also be implemented in motors, for example, where it records extreme vibrations and heat, which usually precedes failure. Analyzing these data during maintenance cycle can reduce chances of catastrophic failure. Finding out the problem before it becomes very costly. So in summary of the NFC's tag application and usage, we can use it in co-chain management that ensure product quality as it travels from warehouse to end customer. Smart building could use it to protect structural degradation. Agriculture sector can benefit from humidity, temperature and light measurement. Sensor tag can also be embedded into clothings or affixed to the skin to alert athletes of dehydration. Use the check because patients vital signs and so on. In terms of deliverables, as we have seen or discussed, the actual hardware of the sensor tag itself, as you can see the picture on the left. The hardware can be bought online through distribution such as mouse or digit key. Once available. On SC.com, one can also download the firmware to source codes of the firmware within the SCM32L0. The global files, the schematics, mobile apps can be retrieved from iTunes and Google Play. Documentation and absolutely support of FE in terms of sensors, microcontrollers and NFC. For smartphone application, you can retrieve the Google Android app on Google Play. And the similar app is available on the App Store for iOS. The Android apps comes with many capabilities. It allows you to log information, change configurations such as time intervals of log. It also allows you to log min-max values such as maximum values of minimum value of temperature sensors, humidity, pressures and accelerometer. You will show a charge, the plot of the information. In detail, it can show you the actual data in individual data points. You can also export the data to a CSV file. So that can be analyzed using all the application. It also has the one shot energy harvesting mode for battery less operation. When you tap with a phone or reader without battery, you can measure the information from the sensor tag at that moment in time. It also logs events such as the orientation of the text. Now for iPhone support, as you have already known, some time ago Apple announced the NFC support for reader mode. And this started to happen in iOS 11 supporting iPhone 7 and higher. So iPhone 8, iPhone 10 and beyond. The capability of iOS 11 currently is that it can read tags from type 1 to type 5 with in-depth information only. And one would need an iOS application. It does not natively identify information or in-depth information at the tab. Similarly to Android, you have to run an app. And of course, you can download the NFC sensor tag app on iTunes. This is what you would see when you run the iPhone app. First, the reading screen showing you to tap with the phone. And notice that the NFC antenna is very much to the top of the phone. So unlike a lot of different Android phones, it's not in the middle of the back of the phone, but it's more to the top of the phone. When you're ready to scan, you simply place in proximity within a few centimeters or two centimeters of the NFC sensor tag. A graph with display to show all the data that are being stored in the tag. Here an example of acceleration information. You can also use a PC to exercise the NFC sensor tag. We have the SC25 PC NFC software. And to get it, you can go to the link down below to download it. And it would require you to have the SC25 or 3911B discovery board. You can also use a type of reader known as the LR1002. It makes by Feg. And these are the reader currently supporting the SC25 PC NFC software. Here's a display of what you can see when downloading sensor data from the tag. It shows similar screenshot from the app's temperature pressure humidity acceleration. It has the ability to trigger at certain sensor event and configure the data such as time interval and so on. Some of you may have noticed that there is a black connector, the back of the NFC sensor tag. That connector is used to download the firmware of the SCM32L0. To do that, you would need a nuclear board. This is a quite popular board that you can find in different distributions such as Digi-Key and Mouser. This smart tag is programmed using the ST-Link V2 in-circuit debugger and programmer. And this section is shown in the yellows. You can break this board in half, retaining the ST-Link section the smaller part. Now you will connect it according to figure on the left. Make sure that the battery isn't its holder. You will need the tag to be powered during this operation. There are two ways to get the binary file into the SCM32L0. One of the ways is simply plug this board, the ST-Link board via USB to your computer. Once you connect it, it will be recognized as a USB drive for example. You simply drag and drop the bin file, the binary image, onto the drive and you will notice the LED stop blinking. And that signals that the firmware is being programmed into the SCM32L0. When it's completed, you can remove the sensor tag and start the operation as normal. You can also use the software that is known as the ST-Link Utility available on SC.com. From there, it allows you to open the file, read the file and do the target program and verify. Well thank you for your time and attention.