Development of very low frequency (VLF) data acquisition system using Raspberry Pi

Abstract

Space weather is an important area of research. The Space Weather Monitor program was introduced by Stanford SOLAR Center with the aim of building and distributing inexpensive ionospheric monitors (SID). These are used to detect changes to the Earth's ionosphere which are caused by solar flares and other ionospheric disturbances that might affect very low frequency (VLF) radio propagation. SuperSID that has been developed by Stanford SOLAR Center for SID detection is a low cost but sensitive space weather monitor which is currently being used around the world. Since 2010, UKM has participated in the “International Space Weather Initiative (ISWI)” and this program has given positive impact and triggered Malaysian students' interest in space science at the secondary school level. In 2012, researchers at University Kebangsaan Malaysia (UKM) succeeded in building their own VLF receiver system, known as the UKM-SuperSID for SID detection, effectiveness determination and development of a teaching kit for SuperSID Introductory Project. However, for both systems, a desktop PC is needed in the existing system to run the SID program and to save the data for further analysis. Thus, power consumption, cost and size of the computer are becoming limiting factors for educators in Malaysia who wish to attract the interest of the young students in Science, Technology, Engineering & Mathematics (STEM) education. This is mainly because the UKM-SID system currently comprises of a loop antenna, preamplifier, sound card and a computer where the computer is required to capture, analyze and save the data, making it difficult to bring it to schools and the community. To overcome this problem, a portable VLF data acquisition system using Raspberry Pi was proposed to detect SID in this study. This system consists of a VLF receiver, preamplifier, analog to digital converter (ADC) and Raspberry Pi. The acquisition software was compiled with Python and run in the Linux environment. As a result, a portable VLF acquisition system using Raspberry Pi has been successfully developed which is able to detect and monitor frequencies transmitted from FTA (16.8 kHz), France and NWC (19.8 kHz), Australia.