Indoor and outdoor air pollution are associated with particulate matter concentration of minute size that deeply penetrates the human body and leads to significant problems. These particles led to serious health problems and an increased spread of infection through airborne transmission, especially during the COVID-19 pandemic. Considering the role of particulate matter during the spread of COVID-19, this paper presents a smart wireless sensor node for measuring and monitoring particulate matter concentrations indoors. Data for these concentrations were obtained and used as a risk indicator for airborne COVID-19 transmission. The sensor node was designed to consider air quality monitoring device requirements for indoor applications, such as real-time, continuous, reliable, remote, compact-sized, low-cost, low-power, and accessible. Total energy consumption of the node during measurement and monitoring of particulate matter concentration was minimized using a low-power algorithm and a cloud storage system embedded during software development. Therefore, the sensor node consumed low energy for one cycle of the particulate matter measurement process. This low-power strategy was implemented as a preliminary design for the autonomous sensor node that enables it to integrate with an energy harvester element to harvest energy from ambient (light, heat, airflow) and store energy in the supercapacitor, which extends the sensor node life. Furthermore, the measurement data can be accessed using the Internet of Things and visualized graphically and numerically on a graphical user interface. The test and measurement results showed that the developed sensor node had very small measurement error, which was promising and appropriate for indoor particulate matter concentration measurement and monitoring, while data results were utilized as strategic tools to minimize the risk of airborne COVID-19 transmission.

The indoor environment climate should be controlled by continuously maintaining the temperature and relative humidity to achieve thermal comfort. A monitoring system of both parameters is the first step to improving indoor comfort quality. This paper presents a smart wireless climate sensor node for indoor temperature and humidity monitoring with a powering strategy and design approach for autonomous operation. The data logging results are sent to the cloud using Internet of Things protocol for thermal comfort monitoring and analysis. The monitoring and analysis results are useful to monitor and control the indoor thermal comfort condition for room occupants. A sensor node was designed that includes a low-power mode and compact size features. It consists of a built-in AVR-based microcontroller, a temperature and humidity sensor, and a wireless module with a supercapacitor as the power storage. A low-power algorithm and Internet of Things system were implemented to reduce the total energy consumption as low as possible during operation while improving the thermal comfort quality. This developed sensor node has a small error for temperature, and relative humidity sensed values resulting from calibration. At the same time, it also consumes low power for one cycle of data acquisition. The device was integrated with an Internet of Things monitoring system to monitor indoor thermal comfort in the field experiment. The experiment results showed that the indoor temperature and relative humidity were measured and recorded in the range of 25–30 °C and 30–40%, respectively. This prototype is a preliminary design to achieve an autonomous sensor node with a low-power energy consumption goal. Thus, with this feature, the developed sensor node has potential to couple with a micro energy harvester module toward a fully autonomous active node in further development.

Several studies reported the significant effect of indoor air quality on human health, safety, productivity, and comfort because most humans usually conduct 80%–90% of their activity inside the building. This is generally due to the fact that indoor pollution is associated with volatile organic compounds (VOCs), pollutants with chronic health effects, both non-carcinogenic and carcinogenic, on humans. Therefore, this study focused on developing wireless VOCs sensor nodes with a low-power strategy feature to perform an autonomous operation in indoor air quality monitoring (IAQM). The sensor node mainboard consists of a microcontroller-based AVR (ATmega-4808) that supports a low power mode and low-power IAQ-Core sensor for VOCs detection. The low-power sensing algorithm developed also allowed the sensor node to consume a total power of 0.22 mAh for one cycle of operation, which includes the initial process, TVOCs value reading process, data transmitting process, and low power mode process at a time interval of 30 min. The most significant power was observed to be consumed in the data transmitting process with 0.13 mAh or 58% of total power consumption in one cycle of sensor node operation. Furthermore, the 10F capacitance of the supercapacitor was able to drive the VOCs sensor node for 139 s and it was recommended that further studies use micro energy harvesting (from an indoor environment) to extend its lifetime. The 1541-minute field experiment conducted also showed that TVOCs and CO₂ values were successfully measured and displayed over an internet connection on the monitoring terminal dashboard. The recorded real-time TVOCs value of 175 ppb (<200 ppb) indicates good air quality.

Data security is one of the factors which evaluating airport service quality, starting with passenger verification and baggage management. QR Code technology security that is widely applied at this time is still considered lacking because of its characteristic that must be seen by the reader so that data can easily be copy through a camera or other image capture device. In this case, Radio Frequency Identification technology (RFID) can be applied because of its characteristic that does not require line of sight so that the data becomes safer. One of the developments of RFID technology is Near Field Communication (NFC) that enables data to be exchanged with a distance of no more than 10 cm so that in practice it very difficult to copy data between the sender and receiver because the range is too close. But, even with the right device, the data is can easily be copied, then the data encryption methods need to be added so that even though the third party succeeds in getting the data, the data can not be read. This research aimed to create a passenger and baggage management system in the airport using NFC technology. The encryption method used to secure passenger data is homomorphic cryptography. This method can simplify the encryption process and the addition of encrypted data. As the results of the testing, this system can secure data transactions because the communication distance is very close with the amount is 2 cm, then the type of tag that can be used is Mifare with 14443A standard. Finally, this system can be used to secure short-distance transactions that require the supervision of its users.

In recent years, portable electronic devices such as gadgets, tablets, mp3 players grow rapidly as daily devices for supporting people activities. In many applications, portable electronic devices need power backup. Since wireless power technology has been introduced in mobile device applications, portable power backup has become more popular to extend the battery life of mobile devices, moreover, the power backup technique also can utilize the advantages of wireless power technology. This paper presents the development of a dual-mode power bank: wireline and wireless, especially for gadget device power charge applications, to enhance user experience. The power backup is stored in a Li-ion rechargeable battery where the power in-outlet is monitored by the power monitoring module. The developed device was designed in a compact, simple, and portable module in the fashionable casing regarding the wireless power bank device. Concerning the wireless system, it was also designed based on Qi-standard Wireless Power Consortium (WPC), working at an operating frequency of 110kHz, maximum transmission distance at 10mm, and providing power at 5W. Experimental and validation reveal that the device can provide power 5V at maximum current 1A. The power transfer efficiency is around 70% and compatible with Qi-standard wireless power charger either modular or built-in inside portable electronic devices.