LoRa enabled Real-time Monitoring of Workers in Building Construction Site

41 Website: www.ijeer.forexjournal.co.in LoRa enabled Real-time Monitoring of Workers in Building ░ ABSTRACTIn construction, the real-time monitoring of the worker is necessary for ensuring safety in terms of health and accidents. The technology advancement in the sensors and wireless communication technology has inspired to implement Internet of Things (IoT) real-time monitoring in construction site. With this motivation, in this study we have proposed a system that is powered with long range (LoRa) and IEEE 802.15.4 based Zigbee communication for real-time implementation. Worker health monitoring mote, helmet detection mote, shoe detection mote, and glove detection mote are the primary components of the proposed system. In addition to this, a local server is embedded to supervise all the primary components and interconnect with gateway to log the real-time data on the cloud server for real-time implementation. As proof of concept, one of primary component i.e., health monitoring mote is implemented in the construction site to measure temperature and pulse rate of the work. In future, the remain components will be implemented in construction site, for the implementation of complete system in realtime. The current study enables to monitor the worker in the construction site and assist to respond immediately in case of emergency.


░ 1. INTRODUCTION
The construction sector is identified as important economic backbone of a country due to multiple categories of construction projects along with the importance of huge endusers [1]. Construction projects are highly beneficial but they are usually vulnerable to a range of unknown hazards and remain one of the riskiest sectors to work with because of events at all occurrences [2]. If the risk analysis is not evaluated properly in the building project's lifetime, then these risky scenarios may lead to life-threatening [3,4]. Health and safety are two important factors that keeps the workplace essentially free from possible hazards of injury and provides the necessary protective equipment. It is concerned with the growth, advancement, and management of the working environment [5]. In traditional method, it is bit challenge to monitor the status of workers in the construction site. In order of enhancing the monitoring of the workers in real-time assists to minimize health related incidents and other kind of accidents. The implementation of wireless sensor network (WSN) in the construction industry enabled to connect the different elements of the construction site through wireless sensors and communication protocol [6] [30].
person of different age group for evaluation.
The organization of the study is as follows, section 2 covers the background, section 3 covers the system description; section 4 covers the results and the conclusion of the article in the conclusion section.

░ 2. PRIOR ART
Construction hand tools are widely utilized and may be found on construction sites all around the world. To carry, make, and install building components for their homestead, human ancestors created and used a variety of hand tools. Construction methods evolved and productivity rose with the introduction of hand tools, although workforce habits on the field altered as well [8]. However, data suggests that when hand tools, particularly power tools, are utilized in a variety of situations, they can cause a variety of injuries [9]. Investigation of construction operations concerns and discovered that practitioners regularly use powered and hand tools as a valuable asset, but they can also be risky [10]. The construction industry has always been considered of as an employment one, with hand tools being employed for a large portion of the work. New technology that assists construction workers, on the other hand, may have irreparable consequences if utilized incorrectly, recklessly, or in a harmful manner.
In 2007, manufacturing workers were the most frequently injured by hand tools, according to Hong Kong occupational injury statistics; nevertheless, construction workers were the most injured of all industrial sectors in 2015. The decrease in the number of injuries can be linked to the digital transformation, which includes the use of IoT in manufacturing [11,12]. Two popular recommendations for lowering the risk of tool-related injuries are to use personal protective equipment (PPE) and to upgrade hand tools [13,14]. However, in practice, construction workers are unwilling to wear proper PPE, neglect to wear it, or wear the incorrect type of PPE for a variety of reasons, including: 1) the detrimental consequences of PPE on production; 2) the discomfort of wearing PPE, especially in high temperature weather; and 3) a lack of awareness on importance of wearing PPE and training to wear effective PPE. 4)negligence and not understanding the benefits of personal protective equipment (PPE) and a lack of information regarding the occurrence of frequent injuries and the possibility for death caused by improper use of hand-held equipment.
A study proposed an IoT-based system that uses trustworthy sensors to guarantee that people are wearing adequate PPE when utilizing both powered and non-powered hand-held equipment to minimize the risk posed by this equipment. Rapid building of smart construction sites is now possible because to recent advancements in electrical technology and computer science. Sensor-based safety management has provided designers, engineers, owners, and users with a variety of unique, automated, and smart services, making it one of the most interesting possibilities [15]. Safety management is more very crucial in preventing the occurrence of hazards than handling them after they occur. As a result, early hazard identification is critical for prevention, and large sensor-assisted safety management studies have proposed that a variety of sensors be used to identify hazards earlier on.
A haptic sensor like environmental sensors and biosensors, is directly placed on the object or included within the object that is to be monitored [16,17]. RFID readers and tags are integrated into the traditional construction supply system, dangerous tools and materials were effectively identified and traced from a safe distance [18,19]. Ultra-Wide Band (UWB) RFID was utilized to send huge amounts of data in a timely manner, implementing exact crane posture prediction and security space analysis [20,21]. Several other haptic sensors were also connected together simultaneously in order to extract a variety of building processes and improve safety management. To protect from falls and musculoskeletal disorders, the researchers used motion sensors to capture workers' muscular activity for workplace study [22,23]; Physiological sensors, such as eye trackers, electroencephalography (EEG) sensors, and electromyography (EMG) have lately been used to monitor physiological status for advanced occupational safety and health analyses [24,25].

Existing system for construction safety
General PPE on construction sites consists of many forms of protective clothing for the eye, head, hearing, hand, foot, breathing, and skin. Workers are prone to forgetting or using the improper protective equipment due to the range of protective equipment available. As a result, workers should be encouraged to pick appropriate PPE while on the job, taking into account the following criteria: 1) PPE should be chosen based on the recognized hazards during the building stage; workers. 2) PPE materials and specifications should be chosen in accordance with the detailed construction task. According to the Construction Site (Safety) Regulation, the obligatory PPE for certain activities is coupled with relevant hand tools in Figure 1 [2]. Regardless of the construction operations, hand, head, skin, and boot protections are standard PPE for workers on most construction sites. PPE is selected for various safeguards based on task qualities such as the region and basic materials.

Head protection
Hand protection Leg protection guarantee their safety. The system is empowered with wireless communication protocol and Wi-Fi protocol to provide the sensor data of the workers on the cloud server. This enables authorities to visualize the workers status from any remote location through internet connectivity.
Automating PPE kit

░ 3. SYSTEM DESCRIPTION
The safety of the construction workers at the site is significant element for preserving the health of the construction workers.
Here the monitoring the health status of every worker plays a vital role. As monitoring of health status is possible with the assistance of emergence technologies that are able to empower to establish a real time monitoring system through internet connectivity. However, the real time monitoring is only possible when the construction site is built with advanced infrastructure based on communication and sensor technology.
To realize this kind of system, architecture is specifically proposed to construction site for the safety of workers with the assistance of advance wireless communication and sensors.
The proposed architecture is shown in the Figure 3, where the architecture is integration of four components namely: health monitoring mote, local server, LoRa gateway and main server. As discussed, that to implement real time monitoring system the integration of sensors and communication is required. So here the detection and health mote component are integration of helmet detection mote, worker health monitoring mote, shoe detection system and gloves detection system. Each detection system is embedded on the body of individual workers for monitoring the safety status frequently. This detection system is embedded with the Zigbee RF communication and specific sensors. Sensors and communication allow to sense the physical parameters of an individual worker and communicate it to the local server located at the nearby in the construction environment. The local server records and save the data in its memory storage during interruption of connectivity with LoRa gateway. Local server empowers to act as interconnectivity between the LoRa based gateway and detection system with reliable connectivity. Local server is feasible to communicate with the LoRa gateway as it is integrated with multiple wireless communication protocol namely Zigbee and LoRa. LoRa and Zigbee communication are integrated in the architecture as it provides the open licensed spectrum to communicate the data with low energy consumption. The local server transmits the status of each detection frequently to the LoRa based gateway LoRa gateway is also integrate with the multiple communication protocol, however here the gateway is additionally embedded with Wi-Fi modem for allowing the sensor data of detection system to log on the main server over internet protocol (IP). The reason behind integration of the Wi-Fi modem is, as the RF packets receiving from the detection system doesn't support for logging the data on the cloud server. The data is available in the main server, where the authority is feasible to monitoring the status of each individual worker at every construction site in real time. The authorities can request for the status of an individual through the web application and Mobile app based on main server. This architecture enables to identify the status of workers in terms of number of workers entered into the construction site and number of unauthorized persons tried to enter into premises are available to the authorities on the server. Finally, the complete architecture enables to implement wireless infrastructure and environment in the construction site. In addition, the description of detection system is illustrated below:

Accessories detection and health mote
The "accessories detection and health mote" consists of various modules to monitor the multiple accessories of workers in the construction site to ensure their safety. Helmet Detection Mote, Worker Health Monitoring Mote, Shoe Detection System and Gloves Detection System are the components that come under the accessories detection and health mote. Moreover, an identification detection system is placed at the entrance of the construction site for identifying the worker through RFID technology as shown in figure 4.

International Journal of Electrical and Electronics Research (IJEER)
Open Access | Rapid and quality publishing Research Article | Volume 10, Issue 1 | Pages 41-50 | e-ISSN: 2347-470X This detection system enables to identify and restrict the unauthorized person entering into the construction site.
The circuit diagram for identification detection system is shown in figure 5. It consists of PIR Sensor, RFID Reader, Microcontroller, LCD, Power Supply Unit, Buzzer and 2.4GHz RF Transceiver. This circuit is placed at the entrance of the construction site to monitor if anyone is entering the site. PIR is a passive infrared sensor that continuously monitors the human movement and alerts the microcontroller whenever anyone enters the site, microcontroller read the data from RFID reader to check whether the person is a valid person or unknown person. If the reader reads the RFID card data, then it means person is wearing helmet otherwise he/she is not wearing the helmet. A buzzer is a output device used to alert through sound, it is connected to microcontroller. If a person without helmet or unauthorized person enters the site then the controller rings the buzzer and alerts the nearby people, simultaneously the same information is updated to the local server through RF transceiver.

Health detection mote
The purpose of this module is to check the whether the worker has worn the helmet or not using eye blink sensor. Workers might enter the site with helmet, but they may not wear it throughout their work at the site. Monitoring it continuously is very important to alert the worker and the management to reduce the risk. Googles are attached to the helmet to protect eyes and an eye blink sensor is embedded in to the googles to monitor the eye blink continuously, since helmet and googles are attached if the eyeblink sensor continuously detects the eye lid movement then it means the worker has worn the helmet otherwise the helmet is removed. Since each helmet has a RFID card it can be detected who has removed the helmet, to the worker a buzzer is placed that rings continuously when eye blink is not detected and the same informed is updated to management in the server through RF Transceiver. This mote is interconnected with shoe detection system and gloves detection system through RF communication as shown in the figure 6.

Worker health monitoring mote
Employees in construction site are usually adults and elders; because they work throughout the day rigorously monitoring their health parameters is very crucial in predicting any health issue. This mote checks the health parameters of the worker like body temperature and pulse rate continuously and updates the information through RF communication (Fig.8). The body temperature and pulse rate parameters empower the mote to confirm abnormality in the health of workers. This mote The circuit diagram for health detection of workers is shown in fig.9, to detect the temperature, an infrared temperature sensor MLX90614 is used and to monitor the heart rate pulse sensor is used.

Shoe detection system
Shoe detection system is to detect whether the worker has worn shoes or not using pressure sensor as shown in figure 10. The pressure sensor integrated on the shoe detection system empowers the system to authorizes the person is wearing the shoe or not. This indeed interconnects with the helmet mote through RF transmitter. The helmet mote will alert the person in the form of alarm to wear the shoes. The schematic diagram of shoe detection is shown in figure 11. To detect the pressure Force Sensing Resistor (FSR) Sensor is used and buzzer to alert the worker and RF module to communicate wirelessly.

Gloves detection system
Gloves detection system is used to check whether the worker has worn Gloves or not using touch sensor. The detection system is also interconnected with the helmet mote through RF transmitter as shown in the figure 12. The touch sensor integrated in the detection system authorizes the person whether wearing gloves or not. Touch sensor is configured as digital sensor, logic 1 and logic 0 represents two states: wearing of gloves and not wearing of gloves, based on the logic received from the touch sensor, the microcontroller will take appropriate action ( figure 13).

LoRa based gateway
LoRa based gateway empowers to log the sensory data of the mote on the main server. In the main server, the sensory data is visualized with respect to Identification allotted to each detection system of the individual. Moreover, the gateway handles the multiple communication protocols. Basically, the sensory data need to convert into internet protocol (IP) packets for logging on the main server. So here the gateway integrates the IEEE 802.11 based Wi-Fi module for transmitting the data received from the 433MHz LoRa to the main server as shown in figure 16.

░4.EXPERIMENT IMPLEMENTATION
In this section, we present the implementation of the proposed system at construction site by evaluating the performance of the certain components like the health monitoring mote. In the health monitoring mote, the two major sensors integrated are the temperature sensor and pulse rate sensor. The pulse rate sensor works on the basis of photoplethysmography. It monitors the change in blood volume via any organ of the body that results in a change in light intensity through that organ. The MLX90614 is a high-precision temperature sensor with an output voltage that is proportional to the temperature in degrees Celsius. It works with I2C protocol and very reliable sensor for accurate temperature reading. It is 4-wired sensor 2 wires are connected to power supply namely Vcc and Ground and the other two pins are SDA and SCL (serial data and serial clock) Any form of calibration or trimming is not necessary in the LM35 series sensor to give accuracy of 1/4°C at room temperature and 3/4°Ccover a full temperature range of -55 to +150 °C. Control circuitry is simplified by the LM35's linear output, low output impedance, and reliable calibration. Figure 17 illustrates the mechanism of the worker health monitoring mote with temperature and pulse rate sensor. During the firmware embedding in the health monitoring mote, the threshold temperature value and pulse rate of the worker are preset. This threshold value assists to conclude whether the worker health status is normal or abnormal. Moreover, the normal pulse rate of the healthy person in the table 2 are also considered for setting the threshold value.
As shown in the figure 17, initially the sensor initiates the temperature sensor and pulse rate sensor for sensing the temperature and pulse rate value of the worker with certain interval of time. If the temperature and pulse rate of the worker are above the threshold level, then the health mote alerts the person on helmet detection mote to initiate immediate action for avoiding serious condition. Moreover,  Figure 17: Mechanism of health monitoring mote ░ 5. RESULTS Table 2. illustrates the results of the health monitoring mote and the corresponding graph is figure 19, x-axis represents the age of the worker and y-axis represents the value of body temperature and heart rate measured through the health mote. Here we integrated the health monitoring mote on 8 different workers with different age groups. We have evaluated the pulse rate values of the workers with the normal pulse rate as shown in the table 1 and the corresponding bar chart graph is shown in figure 18. The values conclude that the pulse rate sensor and temperature value of the health monitoring mote is obtaining the pulse rate values and temperature values are in the normal range only. It is concluded that the proposed health monitoring mote is able to obtain the precise sensor values of temperature and pulse rate of the construction workers.