LED merilnik jakosti signala : diplomsko delo

Leben, Klemen (author), Beguš, Samo (mentor)

Osnovna ideja je bila izdelava VU metra, ki zajema signal s pomočjo vgrajenega mikrofona ali avdio vtičnice. Za procesiranje signala sem uporabil mikrokrmilnik Teensy 3.2 skupaj z dodatno avdio ploščo za hitrejše procesiranje podatkov. Teensy se programira v okolju »Arduino Sketch«, ki temelji na programskem jeziku »C++«. Za prikaz sem uporabil dva LED trakova, kjer vsak LED trak prikazuje svoj kanal. Dodatno sem uporabil tudi linijski izhod, na katerega lahko priključimo slušalke in v realnem času poslušamo hrup, ki ga krmilnik zaznava na vhodu. Kasneje sem dodal LCD zaslon z ločljivostjo 320x240 slikovnih točk. Na zaslonu je prikazan trenutni aktiven vhod in raven jakosti signala. Za mikrofon je bila v gluhi sobi na fakulteti narejena kalibracija. Pri procesiranju signalov, zajetih s pomočjo mikrofona, pa sem implementiral še frekvenčno uteževanje (»A«). To se zelo veliko uporablja pri merilnikih jakosti signala in je definirano v standardu IEC 61672:2013. Namen frekvenčnega uteževanja je približati odzivnost mikrofona človeškemu ušesu, in sicer tako, da pri procesiranju signala izločimo frekvence, ki soprispevajo k računanju hrupa, ki ga človeško uho ne zaznava. Na koncu sem vse elemente sestavil skupaj v ohišje, ki sem ga narisal v programu Creo Parametric in ustvaril s pomočjo 3D tiskalnika. Končna verzija merilnika jakosti signala prikazuje raven jakosti hrupa na zaslonu in LED trakovih ali pa za zajem signala uporablja telefon, ki predvaja glasbo.

• Language: Slovenian
• Keywords: VU meter, merilnik jakosti signala, mikrofon, 3D tiskalnik, jakost hrupa, mikrokontroler
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FE - Faculty of Electrical Engineering
• Place of publishing: Ljubljana
• Publisher: [K. Leben]
• Year: 2021
• Number of pages: 53 str.
• PID: 20.500.12556/RUL-127090
• UDC: 621.317.7(043.2)
• COBISS.SI-ID: 73587203
• Publication date in RUL: 17.05.2021

LEBEN, Klemen, 2021, LED merilnik jakosti signala : diplomsko delo [online]. Bachelor’s thesis. Ljubljana : K. Leben. [Accessed 28 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=127090

Secondary language

• Language: English
• Title: LED VU meter : visokošolski strokovni študijski program prve stopnje Aplikativna elektrotehnika

Abstract

Basic idea was to make a VU meter that captures signal with a built-in microphone or a audio socket. For data processing was used Teensy 3.2 microcontroller soldered together with the audio card for faster data processing. Teensy 3.2 can be programmed in program »Arduino sketch«, which is based on programming language »C++«. Two LED strips were used to display current power of detected signal. Each LED strip for each channel. Later was added LCD screen with resolution 320x240 pixels. On display is shown active input and signal strength level. Additionally, was added line-out on which we can connect headphones and listen to the processed noise detected on input. A calibration was done for microphone in anechoic chamber in faculty. Additionally, was implemented frequency weighting (»A«), which is widely used in noise meters and is defined in the standard IEC 61672: 2013. Its purpose is to bring the microphone's response closer to the human ear, so the process unit exclude unnecessary frequencies that contribute to the calculation of noise that the human ear does not detect. At the end, all parts were assembled together into the housing, which was drew in Creo parametric and was created with the 3D printer. The final version of the noise meter displays the signal strength level on the screen and LED strips, or the signal is captured by a phone that plays music.

• Keywords: VU meter, noise meter, microphone, 3D printer, noise level, microcontroller