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Low-cost wireless mesh communications based on openWRT and voice over internet protocol Nina Siti Aminah; Muhamamad Reza Ramadhani Raharjo; Maman Budiman
International Journal of Electrical and Computer Engineering (IJECE) Vol 11, No 6: December 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v11i6.pp5119-5126

Abstract

Technology makes it easier for us to communicate over a distance. However, there are still many remote areas that find it difficult to communicate. This is due to the fact that communication infrastructure in some areas is expensive to build while the profit will be low. This paper proposes to combine voice over internet protocol (VoIP) over mesh network implemented on openWRT router. The routers are performing mesh functions. We set up a VoIP server on a router and enabled session initiation protocol (SIP) clients on other routers. Therefore, we only need routers as a means of communication. The experiment showed very good results, in the line-of-sight (LOS) condition, they are limited to reception distances up to 145 meters while in the non-line-of-sight (NLOS) condition, they are limited to reception distances up to 55 meters.
Sistem Monitoring Konversi Wifi-RSSI Menjadi Jarak Antar Device dan Router Menggunakan Node-Red Pada Pengembangan Sistem Navigasi Dalam Ruang Rifqi Nafis Mubaroq; Nina Siti Aminah
Proceedings Series on Physical & Formal Sciences Vol. 1 (2021): Proceedings of Smart Advancement on Engineering and Applied Science
Publisher : UM Purwokerto Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (992.367 KB) | DOI: 10.30595/pspfs.v1i.130

Abstract

A global positioning system (GPS) is often used as a tool for determining direction and positioning. However, GPS is weak in estimating the error, which is quite large at the actual distance, so positioning in a narrow area cannot work well. Therefore, a better method is needed to be used as a narrow-navigation system. This study aimed to determine whether RSSI has a better error than GPS for navigation devices in a narrow space or area. The method used was plotting graphs using Ms. Excel and determining the value of R square. The RSSI value was obtained through the Esp8266 device and then sent to the server via the MQTT protocol and converted using Node-Red on the Raspberry Pi. The comparison results of the Esp8266 device RSSI graph match the Laptop RSSI device as a reference. The match between the relative distance to the RSSI with the actual distance shows a 3.3-33% error. This result is considered much better than the GPS error.
Pengembangan Prototipe Alat Pengukur Medan Magnet Menggunakan Sensor Magnetik 49E Rechan Zahrotun Nur; Nina Siti Aminah; Akfiny Hasdi Aimon
Jurnal Fisika Unand Vol 13 No 4 (2024)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.13.4.573-578.2024

Abstract

The magnetic field is an interesting physical phenomenon and found in everyday life. Many currents technological developments are applications of the magnetic field concept, such as electronics, electric motors, fast trains, and others. In this research, a prototype for measuring magnetic fields was developed with a physics instrumentation system. This prototype can be used for experimental measurements of magnetic fields for physics lecture in the school. It was found that a magnetic field measurement tool could be made using a physics instrumentation system. So, this tool can be used as an experimental medium for measuring the magnitude of the magnetic field in permanent magnet and wires carrying electric current. The prototype was consisted a 49E magnetic sensor. It is hoped that the prototype can replace the Gaussmeter or Teslameter which are relatively expensive. The prototype magnetic field measuring instrument was calibrated by comparing the magnetic field strength measured by the 49E sensor with the Lutron GU-3001 Gaussmeter. Measurements are observed at the centre of the object and parallel to the position of the measuring instrument. The results of the measurements show that the average magnetic field strength on the Gaussmeter and 49E sensor is 246.7 μT and 487.3 μT for permanent magnet and 51.2 μT and 96.9 μT for coiled wires.