LoRaWAN complemets the Smart City IoT infrastructure. Meet the Masters module with STM32WL microcontroller.


 
Applications based on LoRaWAN are naturally used in smart citiy and smart factory applications as part of the still developing trend related to the Industry 4.0. Intelligent devices require a combination of many areas and during their design, there may arise problems with choosing an appropriate hardware, ensuring appropriate connectivity and software. However, smart devices producers can take advantage of ready-made solutions On the market we can find universal modules that significantly facilitate and improve the work of engineers and constructors. Such modules enable a quick transfer of an idea from the virtual area to a prototype, and then a commercial solution.

IoT applications – challenges with hardware

In practice, adaptation and implementation of the Internet of Things solutions face many problems. The most significant challenge for engineers and designers is focused on the constraints in the area of energy consumption and range, which means that minimum energy requirements must be met with maximum range.

Lack of sufficient amount of energy over a long time unit for battery solutions that do not possess the possibility of recharging from renewable sources (e.g. photovoltaic panels, mechanical and piezoelectric generators, etc.) means the necessity to limit the frequency of interaction of devices with data storage systems.

Insufficient energy level in IoT applications usually generates the need to limit the power of the communication part, which in turn reduces the range. This means reducing the business value of the solution and makes investments and implementation on the market unprofitable, which is what we as users ultimately lose.

Striving to ensure wireless communication in IoT solutions requires making a decision on the selection of the appropriate communication technique, which is associated with the choice between working in licensed and unlicensed bands.

Basing communication on the GSM network makes it possible to transfer a large part of the burden to the telecommunications infrastructure, but it has consequences in the form of fees and restrictions related to with increased energy consumption. Choosing CAT.M or NB-IoT communication significantly improves the energy balance. However, for many solutions it is still an unacceptable level.

In such a case, a solution worth considering is to use a communication technique operating in the unlicensed band, closest to the security level and universality of the GSM network. The second aspect is to ensure that energy consumption is reduced by several orders of magnitude.

płyta ewaluacyjna STM32WL z LoRa

LoRa WAN – how does it work and what are the benefits?

Only a few years have passed and LoRaWAN has become one of the most popular communication techniques used in Internet of Things devices. Increasing popularity is favoured by the continuous increase in demand for possibly maintenance-free battery solutions or powered by publicly available energy. The dynamic increase in the number of applications is the result of the properties that underlie the assumptions of this network. The most important goal is to ensure the maximum range while optimizing energy consumption. Transmission takes place in unlicensed bands in a star topology in two logical layers:

  • physical – LoRa modulation with spectrum spreading that changes the frequency over time while maintaining a specific bandwidth
  • MAC – defining the protocol enabling communication within the LoRaWAN network.

This type of solution guarantees high resistance to interference. As a result, the appropriate level of propagation translates into ranges. In non-urbanized areas it is up to 30 km, and in highly urbanized areas up to 2 km depending on propagation conditions.
As a result, the LoRa transmission capacity is available in the range of 0.3 – 50 kbps. The solution is suitable for services that do not require real-time data transmission where periodic communication is acceptable.

The LoRaWAN extended star topology consists of end-points and gateways. The purpose of the gate is to aggregate communication from devices and send data to a dedicated, indicated network server. By design, the gate for end devices should be transparent. The exception is the management of access rights.
The continuous development of LoRaWAN now makes it possible to successfully locate end devices by measuring the level of signals using a mathematical triangulation method.

płyta ewaluacyjna STM32WL z LoRa

From an idea, through a prototype to a commercial solution

Prototyping is a necessary, but unfortunately, expensive design stage. Prototyping precedes implementation, engages resources and valuable time of project teams. By definition, it is complex and uncertain about the end result. The purpose of prototyping is to enable the verification of mechanical and electronic assumptions, identify functional problems before starting production, and ensure optimization of mass production costs. As a result of all these activities, the prototype serves as a demonstration device with the possibility of transferring some or all of the know-how directly to a commercial solution.

Masters evaluation board with world’s first LoRa SoC accelerating the prototyping phase.

Masters evaluation board is based on the STM32WL radio chip from ST Microelectronics. The module is made in SoC technology. It integrates a transceiver with LoRa modulation with an efficient microcontroller equipped with a Cortex M4 core. The STM32WL chip is a prioneer of the STM32 family for sub-GHz wireless connectivity, offering ease of use and reliability.

The distinguishing feature of the Masters STM32WL evaluation board is that it provides the user with a prototype platform that is equipped with the most essential elements necessary at the prototyping stage without the need to run additional cables. The board contains a built-in PIFA antenna by Proant, which is characterized by high stability and resistance to frequency detuning, even in close proximity to metal elements or hands.

Masters evaluation board with STM32WL has an SMA socket for external antennas and gives the possibility of testing wherever the requirement during application adaptation is the need to use a remote antenna with high energy gain.

Switching between the PIFA antenna and the SMA connector is programmable to ensure maximum usability and convenience for the user. The system also uses the HTS221 sensor so that real and time-varying data appear during the tests. The use of a battery means that the system can be a stand-alone solution. The module enables to run the first stage of prototyping in the PoC testing phase.

płyta ewaluacyjna STM32WL z LoRa

The module’s microcontroller is based on the well-known Arm® Cortex®-M4 core, and the radio system is based on the IP core SX126x. The system can operate not only with the LoRa® modulation. It also provides many standard modulations (G) FSK, (G) MSK, BPSK. Thanks to these features, it flexibly fits into wireless applications with LoRaWAN® or with another protocol, e.g. for the needs of IoT applications. The LoRaWAN® stack is available as an option.

The system was developed in the same technology as the STM32L4 microcontroller, thanks to which the STM32WL contains a similar set of digital and analog peripherals and has extremely low power consumption ensuring long battery life.

For worldwide compatibility, STM32WL MCUs are equipped with two high-frequency power amplifiers (15dBm and 22dBm) and a wide operating frequency range (150MHz to 960MHz) to operate in the unlicensed RF Sub-GHz band. STM32WL microcontrollers include built-in hardware features: AES 128- / 256-bit encryption, PCROP read / write protection, and public key cryptography with an elliptic curve encryption engine.

The STM32WLE5 line includes a wide variety of communication features, including up to 43 GPIOs, Integrated DC / DC Converter (SMPS) to optimize power consumption, multiple low-power modes to maximize battery life.

End-to-End service – communication tailored to your application

Ease of prototyping means providing comprehensive solutions, access to the latest evaluation systems and providing access to scalable cloud environments. Masters STM32WL evaluation board is a ready-to-use system that includes hardware and programming. Its use significantly accelerates the prototyping and testing phase. Thanks to the business partnership of Masters and Orange Polska, we can extend the offer with the missing element, i.e. connectivity to LoRaWAN.

Masters and Orange Polska provide customer support at every stage of project development, from knowledge transfer in the form of technical seminars and engineering consultations, through the provision of a hardware platform such as evaluation boards with a comprehensive data collection environment, to design services and large-scale production. Thanks to a holistic approach, customers gain time, save funds and bring the product to market faster. If you are interested, please email us rd@masters.com.pl.

Contact us by email rd@masters.com.pl or phone +48 502 825 627.