MM SCIENCE JOURNAL I 2021 I OCTOBER 4781 LONG RANGE IOT COMMUNICATION ALENA GALAJDOVA, ROBERT RAKAY Technical University of Kosice, Faculty of Mechanical Engineering, Kosice, Slovakia DOI: 10.17973/MMSJ.2021_10_2021038 e-mail to corresponding author: alena.galajdova@tuke.sk The article deals with the design of wireless automation system. The proposed systems compare wireless data transmission devices. The main components and their parameters, which are necessary for building such system and base steps how to create and test a device are described. The created systems can serve as a suitable basis for remote monitoring and control systems in open space applications such as weather system or small-scale home automation system and can be used as an example in the education of students in fields such as Automation or Mechatronics. KEYWORDS Long range, wireless communication, micro system, microcontroller. 1 INTRODUCTION Nowadays more and more systems require or support wireless connection. By creating a seamless connection to a remote location, we can control or monitor various devices and systems. This applies to home and industrial automation too. However, the first wireless systems did not support long distance transmissions or required amplified signal transmission and large antennas. Currently available microcontrollers and communication technologies enable remote communication with small mechanical and technical requirements. This type of solution only concerns the monitoring of home automation systems, such as meteorological stations or other measuring systems based on microcontrollers. Nowadays, the wireless data transmission has replaced wired connection, and the aim of solution is to make everyday life easier and more comfortable for everyone in society [Galajdova 2009, Vagas 2020, Krenicky 2011]. The wireless connection generally allows remote monitoring and control of systems that assist with tasks such as control of lights or heating, ventilation and air conditioning (HVAC), opening and closing of doors, windows and controlling various electrical devices [Simsik 2016, Ketshabetswe 2019]. Every advanced manufacturer is trying to implement some form of wireless interface however not all are suitable for long distance communication. Asset monitoring, security systems, weather stations are just a few of the applications that use long distances wireless communication. All of them can be created using protocols such as: Zigbee, BLE, ESPNow, LoRA, and other RF-based protocols. Each of these communication tools allows from small to long range, lower transfer rates and connection limitations. Despite the limitations of the above mentioned protocols, they can be integrated to measure temperature, humidity, movement, gas, vibration and similar factors. The transferred data doesn´t contain any private information and in the most cases, they are not time-critical nor mission critical [Kar 2017, Vagas 2020]. For the purpose of experimental testing of the system, there is no exact application that would allow remote monitoring, and the devices are tested only as a laboratory model to compare the range of the tested devices and their protocol. The main goal is to create a smooth long range communication channel between transceiver and receiver [Sarga 2018]. The proposed systems consist of transmitting and receiving devices, which are connected first via the LoRa Module and in the second via ESP´s ESPNow protocols (Fig. 1). The input of the system is the temperature and humidity sensor DHT11, while in the second experiment only the direct cyclic message is used as information for transmission between the microcontrollers. The measured value is processed and sent, and the signal strength is also measured. Figure 1. Concept of wireless system with multiple sensors and actuators 2 LORA MODULE LoRa stands for Long range. It is part of LoRaWAN, a long- ranged energy efficient wireless communication technology, which is defined by the LoRa Alliance. As the name of the module suggest it is designed for long distance radio communication. It was developed by the Ai- Thinker company. The device uses SX1278 integrated circuit and operates at a frequency of 433 MHz. By frequency hopping the range 420-450 MHz is available but up to 525 MHz is supported. This module works with a power supply of 1.8 to 3.7 V. During the receiving, the power consumption is less than 10.8 mA, while when transmitting, it is less than 120 mA. When the device is in sleep mode, the consumption is 0.2 μA. The module uses half-duplex SPI communication, with programmable bit rate, which can reach up to 300 kbps transfer rates. The maximum output is +22 dBm, and the sensitivity is - 140 dBm.  ANT Pin is the connector where the spring antenna has to be connected (see Table 1).  GND is the ground pin for 0V and is usually marked as a reference for identifying the other pins.  3.3V is the power pin.  RESET pin, the module resets itself when powered on.