Digital System and Computing

Galang Yanu Achmad Ramadan, Eko Sulistya

Flood disasters frequently cause significant socio-economic losses in developing countries, while many existing early warning systems remain costly, complex, or insufficiently accessible for real-time community use. This study proposes a low-cost IoT-based flood early warning system using a conductive K-0135 water level sensor integrated with a NodeMCU ESP8266 microcontroller and HTTP-based communication architecture. The novelty of this work lies in the use of a conductive sensor with systematic threshold characterization under both static and dynamic conditions to reduce false alarms while maintaining reliable detection performance. The methodology involved sensor characterization through controlled laboratory experiments, including static testing with 0.5 cm depth increments and dynamic testing simulating rainfall splashes. The results show a non-linear increase in sensor output with depth, ranging from 16.3 at 0.0 cm to 565.3 at 4.0 cm. Dynamic testing produced an average maximum output of 424.7, leading to an optimal detection threshold of 425. The integrated system achieved a communication success rate of 100% in delivering real-time alerts via HTTP requests to a web server and Telegram platform. An HTTP error code −11 was observed, corresponding to a timeout condition caused by network latency; however, this did not affect successful alert transmission. The findings are limited to controlled laboratory-scale testing and have not yet been validated under real environmental conditions. Overall, the proposed system demonstrates the feasibility of a low-cost, threshold-based IoT solution for real-time flood early warning applications and highlights its potential for improving community-level disaster preparedness.

Digital System and Computing

Anjelina Daima, Andi Rosano, Trisna Fajar Prasetyo

Open-field tomato cultivation is vulnerable to environmental fluctuations, yet manual monitoring often leads to inaccurate decisions. This study aims to design and validate a low-cost Internet of Things (IoT)-based soil quality monitoring prototype, addressing the gap in accessible real-time alert systems for small-scale farming. The system integrates a NodeMCU ESP8266 with soil moisture, temperature (DS18B20), air humidity (DHT11), and pH sensors, visualized via Blynk and Telegram. Conducted over 14 d with nine experimental units across three soil media (clay, sandy, and humus), the study focused on technical prototype validation. Results indicate the system monitored moisture levels (43–47%) and temperatures (≈30.3 °C) with high reliability. Automated irrigation activated at ≈60% and deactivated at 80% moisture, maintaining an uptime of ≥95%. Sensor verification showed temperature deviations below ±1 °C. Unlike existing greenhouse-centric models, this work implements a multi-parameter sensing framework tailored for open-field conditions using affordable hardware. While this study successfully validates the prototype's operational stability and data synchronization, it is primarily a technical verification; further research is required to evaluate agronomic impacts such as yield and water-use efficiency.

Digital System and Computing

Yurimasanti Rachman, Deden Ardiansyah

Gate security systems in residential areas often rely on manual controls or simple remotes, which limit flexibility, real-time monitoring, and secure access. This study developed an IoT-based automated gate control system using RFID authentication and a web-based interface. The system integrated Arduino Uno, an ESP8266 Wi-Fi module, an RC522 RFID reader, a relay, and a DC motor to automate gate operation, while user activity was monitored through a local web server built on Apache and MySQL. Testing was conducted under controlled indoor conditions with an average Wi-Fi signal strength of -62 dBm, an ambient temperature of 27°C, and a local network latency of 8 to 12 ms. Across 50 trials using five different RFID cards, the system achieved 100 percent reading accuracy, an average response time of 1.42 seconds from tag detection to motor activation, and stable communication with no packet loss. Mechanical implementation using 8.25 kg of galvanized steel and a dual-rail support system ensured stable and smooth gate movement. These results confirm that the system provides secure, contactless, and remotely accessible automated gate control. Future improvements should focus on cloud-based integration and enhanced network stability for real-world deployment.

Digital System and Computing

Lailatul Maulida

Public institutions increasingly depend on IT assets to sustain essential operations, yet many still lack structured risk management frameworks. At TVRI East Java, the absence of a dedicated IT division underscores the need to evaluate asset vulnerabilities and threat exposures systematically. This study identifies and prioritizes critical IT assets and their associated risks using the Quantitative Risk Analysis (QRA) method. Data were gathered through interviews, document analysis, and expert validation. Thirteen IT assets were assessed against fifteen potential threats, and quantitative metrics such as Single Loss Expectancy (SLE) and Annualized Loss Expectancy (ALE) were used to estimate financial impacts. The analysis showed that personal computers are the most critical assets, primarily threatened by computer viruses, while minor peripherals pose minimal risk. Expert verification confirmed that the findings reflect real operational conditions. However, the study’s scope was limited by the reliance on a single expert for data validation, which may constrain the broader applicability of the findings. The results provide a structured basis for risk mitigation strategies and can guide similar institutions in strengthening IT asset management.

Digital System and Computing

Anisatul Mukaramah, Syahiduz Zaman

Organizations are increasingly adopting open-source Human Resource Information Systems (HRIS) due to their cost-efficiency, configurability, and scalability. However, selecting the most suitable platform remains a major challenge due to diverse functional requirements. This study aims to determine the most appropriate Free and Open Source Software (FOSS) HRIS based on key decision-making criteria. A comparative evaluation was conducted on three platforms, IceHRM, OrangeHRM, and Sentrifugo, using the Analytic Hierarchy Process (AHP) to calculate criterion weights and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to rank the alternatives. Seven HR functional domains, including employee management, attendance, recruitment, and payroll, formed the evaluation framework. The results indicate that IceHRM achieved the highest relative closeness score (RC = 0.7892), followed by OrangeHRM (RC = 0.7428), and Sentrifugo (RC = 0.0133). Based on the evaluation model, IceHRM is identified as the most suitable option due to its alignment with prioritized functional criteria. The proposed AHP-TOPSIS approach provides an objective and replicable decision-support model for organizations undertaking HRIS selection as part of digital transformation initiatives.

Digital System and Computing