In this article we explain

• what an NFC microcontroller is
• why it works without batteries
• what dynamic NFC tags and NFC chips are
• the areas in which NFC microcontrollers are used
• what advantages they offer

1. What is a NFC microcontroller?

In simple terms, an NFC microcontroller is a small computer that forms the bridge between the read data and an NFC reader. It can draw its energy from the smartphone's electromagnetic waves.

NFC microcontrollers are connected to an NFC tag and can perform various tasks by processing signals and issuing instructions. The microcontroller is described with a source code that should execute certain commands. The NFC microcontroller can also translate data into NDEF. This is the format in which data must be stored on an NFC tag so that NFC readers such as smartphones can read it. This translated data is stored on the NFC chip.

1.1. But why do you need an NFC microcontroller?

NFC microcontrollers are primarily used for measuring data. Instead of displaying measurement data with a display and a sensor, the NFC microcontroller is a more attractive method:

• Microcontrollers work without batteries and are very energy-efficient, as they can utilize the energy of another device. Thanks to adapted hardware, they generally require less energy than alternative methods such as displays.
• Unlike conventional displays, they are very durable and also work at temperatures from -40 °C to +85 °C.
• Due to their size, they can be easily installed and integrated into products, whereas a display requires significantly more space and costs more.
• They offer significantly more protection against unauthorized access than a simple password in a display.

1.2. We will explain exactly how this works using an example with an NFC sensor:

Imagine you have a small thermometer in your fridge. This thermometer contains a temperature sensor that measures how warm or cold the temperature in the fridge is.

1. Measurement of the temperature

The sensor measures the temperature and then outputs this information as an electrical signal.

2. The microcontroller processes the measurement

• Accepts the information from the temperature sensor: The information is a number in our case, 4 (°C).
• Calculates and processes the data: The microcontroller converts the number into understandable information, such as “Temperature is 4 degrees Celsius”.
• Stores the information or prepares it for transmission: It converts the data into NDEF format and stores it on the NFC chip. Now the temperature measurement is ready to be displayed on another device and can be read out.

3. NFC transmits the data

This is where NFC comes into play:

• When the cell phone is held up to the NFC tag, the cell phone reads out the temperature value, which is stored on the NFC chip, via.
• We find out on our cell phone: The temperature in the fridge is 4 degrees Celsius.

An NFC microcontroller typically contains all the essential components required to enable NFC communication:

• RF transmitter (radio frequency transmitter): Generates the electromagnetic field that enables communication between NFC-enabled devices. NFC typically operates at a frequency of 13.56 MHz.

• Control and processing: The microcontroller contains a control unit and memory to process NFC commands and store data.

• Security mechanisms: Many NFC microcontrollers contain special encryption hardware to make the transmission of sensitive data, such as payment information, secure.

2. Why the NFC microcontroller works without batteries

NFC microcontrollers are particularly environmentally friendly and cost-saving because they can use energy from other devices.

As a rule, the NFC microcontroller is activated by the energy of an NFC reader (e.g. smartphone) during the reading process. For this reason, the cell phone must be held against the NFC tag for longer, as the NFC microcontroller requires a certain processing time. The NFC microcontroller therefore works without a battery and is only activated at the time of reading, e.g. when the refrigerator temperature is read in the morning and evening.

However, there are also cases where continuous reading is desirable.

This is often the case in industrial areas where temperatures need to be monitored continuously over a longer period of time. In these cases, sensors with a battery can be used so that the NFC microcontroller can also use the energy from this battery. Special low-power chip microcontrollers are usually used for this in order to keep power consumption low.

If data is to be measured over a longer period of time and this process is to be checked with a readout, the sensor should be battery-powered. The NFC microcontroller can also use the energy from the battery for this purpose.

If only the measured value is to be measured at the time of readout, a battery can be dispensed with altogether.

3. Microcontroller as part of dynamic NFC tags

A standard NFC tag contains an NFC chip and an antenna. However, if the NFC chip and the antenna are connected to a microcontroller via a contact interface (e.g. I2C), manufacturers now often refer to so-called dynamic NFC tags.

Dual-interface chips are installed inside the dynamic NFC tag. A dual-interface NFC chip (also called dynamic NFC chip) makes it possible to exchange data in two directions between two electronic systems, for example an NFC reader and an NFC microcontroller. This is also possible if the object carrying the NFC tag is not supplied with power. A dynamic NFC chip differs from conventional NFC chips in that in most cases it only communicates with one electronic system, the NFC reader, during the readout process. In our example with the temperature reading of the refrigerator, a dynamic NFC chip is therefore also required.

NFC chips that only communicate with an NFC reader are also known as single-interface NFC chips. These are, for example, NFC chips that contain a link that is to be read, as with NFC business cards. They are passive and do not communicate with other devices such as an NFC microcontroller.

4. Application of NFC microcontrollers in companies

NFC microcontrollers are important for many applications. Their main task is usually to work together with sensors to monitor products or track their location. They are also used in contactless payment and energy harvesting, among other things.

There are many industries in which products need to be checked for various conditions. This is also known as asset monitoring or asset tracking. For this purpose, it is important to measure temperature, light, humidity, pressure, movement or other conditions as accurately as possible. This is usually done with the help of a sensor.

4.1. Asset monitoring / tracking in various areas

Medicine and pharmaceuticals: This is often done in the pharmaceutical sector, where the temperature or condition of a drug must be checked beforehand so that it can be used safely for studies and patients. Here, the microcontroller and interface are installed in vials or syringes.

Industry such as environmental technology: Sensors in conjunction with microcontrollers are also important in industry. One example of this is energy and environmental technology, where the status of machines such as wind turbines, but also soils, must be monitored.

E-scooter as a means of transportation: NFC microcontrollers can be used within e-scooters to determine motion states, for example. It is possible to check whether the e-scooter has fallen over during its operating time, but also whether it is locked or unlocked.

More about NFC in companies: NFC business applications

5. Advantages

Using microcontrollers with NFC technology offers various advantages.

• Energy-saving and environmentally friendly

NFC tags often do not require their own power supply, as they are supplied with energy via the electromagnetic field of the NFC reader. This also powers the NFC microcontroller and sensor during the reading process.

• Secure wireless communication

Due to the short range, the risk of eavesdropping and manipulation is lower than with other wireless technologies such as Bluetooth or WLAN. Unauthorized persons would require direct contact with the NFC tag. Furthermore, hardware with additional encryption algorithms or passwords is often used.

• Wide range of applications

NFC microcontrollers support many industries by monitoring products or machines. They are also used in other areas of NFC technology such as contactless payment and energy harvesting.

• Compact and user-friendly

Microcontrollers are easy to use as they can be easily integrated into existing devices or machines due to their size. To use them, all you need to do is hold the NFC reader to the NFC tag with integrated microcontroller.

6. Conclusion

An NFC microcontroller is a battery-free minicomputer that obtains its energy supply from the energy of a reader or the battery of other devices. This makes it very environmentally friendly and cost-saving. It processes data and then stores it on NFC chips, forming the bridge between data and NFC readers. This enables energy-saving, secure and wireless communication, making NFC microcontrollers ideal for various applications in companies. These areas include medicine, industry and asset tracking.

They are particularly advantageous due to their compact design, low energy consumption and versatile applications, from temperature monitoring to contactless payment.