JAICT, Journal of Applied Information and Communication Technologies Vol.7, No.2, 2022 ———————————————————————————————————— 90 Temperature, Humidity, and Power Outage Monitoring System of Pamapersada Nusantara’s Server Racks Eskandaru Sadewa 1 , Samuel Beta 2 1,2 Telecommunication Engineering, Electrical Engineering Department, Politeknik Negeri Semarang Abstract — Data center is a vital location that must be managed. The room contains central devices that are essential for operational continuity of the information system. Like the PT Pamapersada Nusantara data center, this room needs to be maintained according to standards. One thing that needs to be maintained is temperature, humidity, and electricity because they have a direct impact on IT equipment and can be potentially fatal if they are not in standard conditions. Meanwhile, the data center being researched uses manual checks for temperature, humidity, and electrical power supply. The problem is the inconsistency of the administrator in documenting these parameters and the lack of responsiveness of repairs if an anomaly occurs in the parameter value, because the data is not real time. This research aims to build a monitoring system for monitoring temperature, humidity, and power outage at the PT Pamapersada Nusantara data center which provides direct notifications to administrators. Current similar studies generally do not include the sensor location factor which is essential. The sensor installation is not randomly placed in the room, nor in the hot aisle or in the cold aisle, but in the server rack so that the temperature and humidity truly represent the surroundings of the device as ASHRAE recommend. Referring to ASHRAE, the standard temperature is 18° C - 27° C while the humidity is 20% - 60%. This research starts from a needs analysis through a survey, followed by equipment design, equipment testing by comparing with manual measuring tools. ESP8266 and DHT22 sensors are used, telegram as system output in the form of notifications. Notifications are sent when the temperature and humidity values are not in standard conditions, they are sent every day at 07.00 and 15.00, and they are sent if there is 5% increasing or decreasing values. The results show that the system successfully sends a notification on telegram when the conditions are met. Tests using comparisons with other measuring instruments also show a deviation of values below 2%. Measurements on the server rack show varying value depending on the occupancy of the rack and its position against the air conditioner. Keywords— Data center, IoT, telegram, temperature and humidity monitoring. 1. Introduction Server room / data center is a vital room for information systems management in an institution. The data center contains a collection of IT devices that serve the information transaction needs of the institution. Among them, such as servers, storage, and network devices such as routers, switches and firewalls. They are devices that require high performance to support information system operations. These devices require special treatment regarding the surrounding environment (such as temperature, humidity, voltage, etc.) which must be maintained to maximize the performance of these devices. Data center is divided into 4 tiers. The data center is divided based on aspects of building architecture, electrical aspects, telecommunications aspects and mechanical aspects[1]. TIA-942 is one of the standards used to design data centers[2]. This standard also covers the flow of hot air and cold air in a data center. This hot and cold airflow is designed to maintain the optimal data center temperature for the performance of the servers/devices inside. ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) recommends for data center temperature to be at 18°C - 27°C for class A1 and room humidity to be in the range of 20% - 60%[3]. It is important to maintain this temperature and humidity so that the performance of servers and other devices can run optimally. The temperature must also be monitored to ensure there is no overheating that could cause a fire. ASHRAE also recommends that monitoring for temperature and humidity should be placed in the rack, because it is in the rack that there are devices to be monitored. Recently, a fire broke out in the Cyber 1 Jakarta data center, which was December 2, 2021. According to digital economy researcher at the Institute for Development of Economics and Finance (Indef) Nailul Huda, published in ekonomi.bisnis.com on December 3, 2021. The fire is detrimental to those who have equipment in the building in the number of hundreds of billions of rupiah. Of course, this is a number that is expensive because the losses in the data center are not only damage to devices but also transaction losses that occur due to system downtime. For this reason, it is important to monitor temperature and humidity in the data center to not only maintain server performance but also mitigate the impact of fires. PT Pamapersada Nusantara jobsite SMMS (Suprabari Mapanindo Mineral Sekako), on the other hand, needs to also manage its data center. The company strives to maintain the server room at the recommended temperature and humidity levels. It has one data center whose room size is 24 square meters with three racks in it. Two racks contain network devices, and one rack contains servers. There are