While several communication technologies like LoRa, LTE-M, NarrowBand-IoT (NB-IoT), and Sigfox alphabetical order) are trying to impose themselves as the standard for the Internet of Things (IoT) the market is being flooded with all sorts of low-cost radio modules. The good thing with these modules and technologies is that they are designed for (relatively) long distance operation, something that is difficult to achieve with Wi-Fi or Bluetooth.

 
Dragino LoRa IoT kit contents
Enter the world of LoRa with a Dragino IoT kit.

The idea behind IoT is that objects (edge nodes) send data through a gateway to a (cloud) service from where it is distributed to the data consumers. Although this is a nice concept, for many applications it is too complicated, and one or more peer-to-peer (P2P) connections are sufficient in many situations. Of the aforementioned technologies, currently only LoRa supports P2P (LTE-Direct is on its way). Also, LoRa is subscription free, which explains why it is so popular amongst electronics amateurs.

Waterproof wireless Dragino node

Dragino is a manufacturer of IoT hardware, specialized in Linux IoT/VOIP, Arduino Yùn add-on boards and LoRa modules and gateways. One of their latest products is the LSN50 long-range LoRa sensor node, designed for outdoor use. Built in a sturdy waterproof enclosure (IP66) and powered by a 4,000 mAh Li-SOCl2 battery, the LSN50 targets wireless sensor network applications such as irrigation systems, smart metering, smart cities, smartphone detection, building automation, and so on.

 
Dragino LNS50 LoRa node
Port map of the Dragino LNS50 LoRa node.

ARM Cortex-M0+

The wireless part of the LSN50 is based on the popular SX1276/SX1278 transceivers from Semtech (LoRaWAN 1.0.2 compliant) supporting multiple bands (433/868/915/920 MHz, to be specified when ordering). The wireless modem is controlled by an ARM Cortex-M0+ 32-bit STM32L072CZT6 microcontroller by ST. This MCU, clocked at 32 MHz, features a memory protection unit (MPU), 192 KB flash program memory, 20 KB RAM, and a 6 KB EEPROM plus an extensive range of peripherals (I²C, USART, USB, 18 GPIO pins, two 12-bit ADCs and one 12-bit DAC).