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INDONESIA
GEMA TEKNOLOGI
Published by Universitas Diponegoro
ISSN : 08520232     EISSN : 2656582X     DOI : -
Core Subject : Science,
Computer Science & IT
Gema Teknologi Journal (pISSN : 0852-0232, eISSN : 2656-582X) is an open access journal published by Vocational School, Diponegoro University, Indonesia. Gema Teknologi publishes articles from various engineering disciplines (the results of original scientific research or new scientific studies of literature). Editor receives articles both in English and Indonesian. Gema Teknologi Journal is published 2 (two) times a year, on April and October.
Arjuna Subject : -
Articles 217 Documents
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Rancang Bangun Sistem Monitoring Kecepatan Dan Jumlah Kendaraan Di Jalan Lingkungan Berbasis Sensor Photo Beam Muhammad Irvan Aditya Andreawan; Dista Yoel Tadeus
Gema Teknologi Vol 21, No 3 (2021): April 2021 - October 2021
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i3.90248

Abstract

Neighborhood roads are a form of transportation infrastructure frequently used by residents in residential areas; however, limitations in the monitoring system make it difficult to accurately track vehicle speed and traffic volume, potentially leading to accidents caused by vehicles exceeding the posted speed limit. Therefore, this study aims to design and build a prototype system for monitoring vehicle speed and count using an IoT-based photo beam sensor. The system is designed using a photo beam sensor to detect vehicle paths, an ESP32 as the main controller, an LCD for local monitoring, and a spreadsheet as a medium for remote data storage. The system is capable of calculating vehicle speed based on the time difference between two sensor points spaced 2.5 meters apart, distinguishing between vehicles entering and exiting, and categorizing vehicle speeds as either within the normal range or exceeding the limit, in accordance with Ministry of Transportation Regulation No. 111 of 2015. Test results show that the system operates in accordance with its design logic, demonstrating good accuracy in detecting speed and counting vehicles based on tests conducted on 500 vehicle data points. Additionally, the feature for automatic, real-time data recording in the spreadsheet functioned effectively, thereby facilitating traffic monitoring and evaluation. Based on these test results, the designed prototype successfully performed the functions of automatically monitoring, recording, and classifying vehicle speeds on local roads.
Perancangan Alat Deteksi Kematangan Buah Alpukat Mentega Berbasis ESP32 Menggunakan Sensor TCS3200 dan Sensor MQ135 Dengan Monitoring Google Spreadsheet Hanifan Arya Genio; Arkhan Subari
Gema Teknologi Vol 23, No 1 (2024): April 2024 - October 2024
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v23i1.90338

Abstract

Manually determining the ripeness of butter avocados based on skin color and aroma tends to be subjective, so a more objective measurement system is needed. This study designed an ESP32-based butter avocado ripeness detection device by integrating a TCS3200 color sensor and an MQ135 gas sensor. The TCS3200 was used to obtain red and green color parameters, while the MQ135 was used to detect changes in gases or volatile compounds around the fruit. Data from both sensors were processed using a rule-based system with threshold values derived from testing 50 fruit samples grouped into unripe, semi-ripe, ripe, and rotten categories. The test results showed that red and green values tended to decrease from the unripe to the rotten stages, while MQ135 values increased from 83–88 PPM in unripe fruit to 103–113 PPM in rotten fruit. The system successfully displayed the classification results on an LCD screen and automatically sent the readings to a Google Spreadsheet via Wi-Fi. These results demonstrate that the integration of color sensors, gas sensors, the ESP32, and cloud-based monitoring can be applied to support the automatic detection of butter avocado ripeness.
Prototype Sistem Proteksi Terhadap Undervoltage dan Overvoltage pada Panel Distribusi Tegangan Rendah Berbasis Internet Of Things (IoT) Khofifah Zhiya Ulhaq; Yuniarto Yuniarto
Gema Teknologi Vol 22, No 1 (2022): April 2022 - Oktober 2022
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v22i1.90230

Abstract

In this modern era, the stability of electrical systems plays a crucial role in sustaining various aspects of human life. Particularly in households and industry, a reliable and high-quality electricity supply is essential. However, electrical systems often face disruptions. Among these disruptions, overvoltage and undervoltage are serious concerns due to their significant impact. In this final project, the author designed a prototype system to protect against overvoltage and undervoltage in low-voltage distribution panels based on the Internet of Things (IoT). The goal is to minimize damage to electrical equipment caused by overvoltage or undervoltage. This prototype utilizes an Arduino Mega 2560 as the control center, collects data from a PZEM-004T sensor to measure electrical parameters, and displays the information on an LCD screen and via the Blynk app on a smartphone. The protection system in this thesis is designed to operate automatically upon detection of undervoltage or overvoltage. Based on the results of the experiments conducted, the IoT-based overvoltage and undervoltage protection system for low-voltage distribution panels is capable of cutting off the power supply to the load when overvoltage or undervoltage occurs. Alerts are provided via a buzzer and notifications on the Blynk app. In addition, the real-time monitoring system for voltage, current, and power per phase also functions as intended, with consistent and accurate data displayed on both the LCD and the Blynk app. Voltage measurements using the PZEM-004T sensor demonstrate excellent accuracy, with an error of 0.26% and an accuracy rate of 99.74%.
Rancang Bangun Trainer Pengatur Kecepatan Motor Induksi 3 Fasa Berbasis PLC Schneider TM221 dan VSD Altivar ATV320 Ismu Baikhaqi Murbiyanta; Priyo Sasmoko
Gema Teknologi Vol 22, No 4 (2024): October 2023 - April 2024
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v22i4.90304

Abstract

The development of industrial automation systems requires electric motor control that is efficient, reliable, and easy to operate. One of the methods used to regulate the speed of an induction motor is by utilizing a Variable Speed Drive (VSD) controlled by a Programmable Logic Controller (PLC). This study aims to design and develop a three-phase induction motor speed control system based on a Schneider Modicon TM221CE16R PLC, Human-Machine Interface (HMI), and Schneider ATV320U15M3C VSD using a three-stage multi-step method. The system was designed with three operating frequency levels, namely 15 Hz, 35 Hz, and 50 Hz. Motor speed measurements were carried out using a tachometer as a reference for the RPM value. At frequencies of 15 Hz, 35 Hz, and 50 Hz, the motor speeds obtained were approximately 450 rpm, 1044 rpm, and 1490 rpm, respectively. These results indicate that the motor speed is directly proportional to the VSD output frequency and closely matches the theoretical values, with minor deviations caused by induction motor slip. Furthermore, the HMI successfully functioned as an effective operation and monitoring interface, demonstrated stable performance, satisfactory accuracy, and ease of operation, making it suitable for educational purposes and industrial automation control applications.
Rancang Bangun 6-DoF Welding Arm Manipulator Robot Berbasis STM32 Alfonsus Giovanni; Fakhruddin Mangkusasmito
Gema Teknologi Vol 22, No 3 (2023): April 2023 - October 2023
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v22i3.90293

Abstract

In the era of Industry 4.0, the demand for automation in the manufacturing sector continues to grow, particularly in welding processes that require high efficiency, consistency, and quality. Robotic arm manipulators have become a widely adopted solution in various countries, including Indonesia. However, the dominance of imported products poses challenges such as high investment costs and limited customization capabilities. This research aims to design and develop a six-degree-of-freedom (6-DoF) welding robotic arm manipulator using the STM32H7 microcontroller as the main control system. The STM32H7 was selected for its high processing performance, low power consumption, and flexibility in integrating sensors and actuators. The outcomes of this study are expected to contribute as an alternative solution for the development of domestic industrial robotics, thereby reducing reliance on imported technologies and supporting national technological self-sufficiency. Several tests were conducted on the developed system, including repeatability testing. The results indicate that the prototype achieved a repeatability value of ±0.225 mm, which is still lower than that of comparable industrial-grade systems (±0.02 mm). This finding suggests that while the system shows promise, further refinement is required to meet industrial performance standards
Rancang Bangun Sistem Deteksi Dini Titik Panas Dan Proteksi Otomatis Pada PHB-TR Menggunakan Sensor Inframerah MLX90614 Berbasis IoT Fenty Nurhaliza; Yuniarto Yuniarto
Gema Teknologi Vol 21, No 3 (2021): April 2021 - October 2021
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v21i3.90272

Abstract

A rise in temperature at the PHB-TR connection terminals due to loose connections can cause hotspots, which have the potential to disrupt and damage the electrical power distribution system. Therefore, this study aims to design and build a prototype system for the early detection of hotspots and automatic protection of PHB-TRs using an IoT-based MLX90614 infrared sensor. The system is designed using the MLX90614 sensor as a non-contact temperature detector, the ESP32 as the main controller, an LCD for local monitoring, MQTT-based web monitoring for remote monitoring, and a Telegram Bot for notifications. The system can display temperature conditions categorized as normal, warning, and danger, and perform automatic protection by tripping the load when the temperature reaches the danger level. Test results show that the system operates according to the design logic, with an optimal sensor measurement distance of 2 cm, an average sensor calibration error of 1.55%, and an average Telegram Bot notification delay of 1.33 seconds. In addition, the reset feature and safety interlock mechanism also functioned properly, allowing the system to resume operation once the temperature returned to normal. Based on these test results, the designed prototype successfully performed its functions of monitoring, early detection, notification, and automatic protection.
Rancang Bangun Floodlight 100 W Dengan Kontrol Kecerahan Berbasis PWM Ninna Nikita Dewi; Dista Yoel Tadeus
Gema Teknologi Vol 23, No 2 (2025): October 2024 - April 2025
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v23i2.90344

Abstract

High-power floodlights are commonly operated continuously at maximum brightness even though lighting needs vary by operating condition. This study designed and developed a 100 W COB LED floodlight with brightness control based on Pulse Width Modulation (PWM). The system used an ESP32 as the main controller, a potentiometer as the PWM input, an IRF540 MOSFET as the electronic switch, a boost converter as the lamp voltage supply, and DS18B20, LDR, and INA226 sensors to monitor temperature, light intensity, voltage, and current. Measurement data were shown on a 16x2 I2C LCD and sent to Google Spreadsheet when Wi-Fi was available, while the control and monitoring functions continued to operate during Wi-Fi disconnection. Testing was conducted through PWM variation, low-PWM operating threshold, Google Spreadsheet logging, fan cooling comparison, and oscilloscope observation of the MOSFET switching signal. The results show that the lamp responded at a very low PWM value, while stable light output was used at about 10% duty cycle. The LDR reading reached 4095 at 80-100% PWM. At 100% PWM, the measured voltage was 30.3 V and the current was 3.28 A, producing approximately 99.38 W. The fan reduced the temperature from 57.4 °C to 42.6 °C, with a difference of 14.8 °C. A 5 kHz PWM frequency produced a more stable light output than lower frequencies. Overall, the developed system was able to control brightness, monitor operating parameters, and record data automatically at prototype scale.
Pengendali Suhu Pada Etalase Fried Chicken Menggunakan Sensor DHT22 Dengan Metode Kontrol PID Berbasis Arduino Uno Cheyla Lokahita Pujiono; Fakhruddin Mangkusasmito
Gema Teknologi Vol 22, No 2 (2023): October 2022 - April 2023
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v22i2.90244

Abstract

The temperature inside a fried chicken display case is an external factor that affects the quality of crispy fried chicken. A heating system is essential to ensure that the crispy fried chicken remains in a condition ready and suitable for consumption. This study implements an Arduino Uno-based temperature control system for a fried chicken display case using the PID (Proportional-Integral-Derivative) control method. The PID method was selected because it offers the desired response characteristics: a fast response with minimal error. An incandescent lamp serves as the actuator, while a DHT22 sensor functions as the feedback component. Testing of the PID parameters yielded values of Kp = 220, Ki = 200, and Kd = 60, with a setpoint of 50ºC. In tests conducted without external disturbances, the system achieved a settling time (ts) of 576 seconds (approximately 10 minutes). When tested in the presence of disturbances, the system demonstrated a steady-state response with a steady-state error of 0.01%, a steady-state duration of 3900 seconds (65 minutes), and a recovery time of 609 seconds (approximately 10 minutes).
Simulasi Sistem Monitoring Suhu Dan Tekanan Internal pada Transformator Daya Berbasis ESP32 Menggunakan Website Dinar Salsabiela; Yuniarto Yuniarto
Gema Teknologi Vol 23, No 1 (2024): April 2024 - October 2024
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v23i1.90331

Abstract

Power transformers are prone to operational failures due to increases in internal temperature and pressure. Given that built-in mechanical protection systems operate only reactively, this study aims to design a real-time early-detection and tank-monitoring system based on the Internet of Things (IoT). This system was developed using an ESP32 microcontroller, a Type K thermocouple sensor, and a pressure sensor. The sensor readings are processed to control safety actuators (buzzer, heater relay, and solenoid valve) based on three threshold conditions: SAFE, WARNING, and DANGER. The system also visualizes monitoring data on a Node-RED website and automatically logs the history via Google Spreadsheet. Test results show that the simulated system successfully responds to changing conditions as designed. When the status is WARNING, the buzzer activates as an early warning. In the DANGER condition, the microcontroller automatically turns off the heater and opens the solenoid valve to reduce pressure. Validation tests recorded a very low average reading error percentage—0.36% for temperature and an average deviation of 1.47 psi for pressure—compared to the reference measuring instruments. Overall, this system simulation successfully performed remote monitoring and protection functions with a high level of accuracy.
Rancang Bangun Deteksi Pencurian Kabel Power Pada Gardu Distribusi Jaringan Tegangan Rendah 3 Phase Mukhammad Khoirurrijal; Yuniarto Yuniarto
Gema Teknologi Vol 22, No 3 (2023): April 2023 - October 2023
Publisher : Vocational School Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/gt.v22i3.90300

Abstract

Power cables at three-phase distribution substations are particularly vulnerable to theft by unscrupulous individuals. This is because the conductors used in these power cables are made of copper, which has a high resale value. Given this situation, a power cable theft detection system was developed using the NodeMCU ESP8266 microcontroller to transmit reading data and alerts to the Arduino IoT Cloud platform, as well as to send warning messages to WhatsApp Messenger via CallMeBot when power cable theft occurs. The parameters used to detect this activity are voltage readings obtained from the PZEM-004T sensor—with an error margin of 0.0036%–0.0049%—and time data obtained from the `millis()` function on the NodeMCU. When theft occurs, the microcontroller will trigger the buzzer and send alert messages to both the Arduino IoT Cloud and WhatsApp Messenger via CallMeBot.

Page 18 of 22 | Total Record : 217

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