PC audio level data over com port? - Page 1
Forum section: electronics / projects

author: Alex
author_rank: Regular Contributor
timestamp: November 04, 2017, 02:07:26 pm
content: Here is a question - I am building a vu meter and I am wondering if, instead of using some analogue audio connection to an audio card, there is a way to pull the audio level data from a PC without writing new software. This could then talk to an arduino over a virtual com port and the arduino controls the display.Are you aware of something that fits this description?CheersAlex

author: Someone
author_rank: Super Contributor
timestamp: November 04, 2017, 10:13:38 pm
content: Seems overly complicated when a vu meter (of the specific analog moving coil type) does everything passively. Historically there were bits of software written for specific music players:https://winampheritage.com/plugin/lcdriver-for-winamp/36370With various amounts of hackery its possible for software to intercept the audio outputs on modern computers:https://apple.stackexchange.com/questions/52129/audio-meter-toolhttp://www.mzuther.de/en/software/kmeter/But I've not heard of any that then turn that into data for output on other interfaces. You'd probably need to do quite a bit of software to achieve what you want.

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 04, 2017, 11:38:22 pm
content: What is the difference between "audio level data" and "audio"? How fast do you want the VU meter to respond? Are you looking for actual accuracy, or just something cosmetic to "wave the needle"? What kind of response time do you want? Real-time peaks, or longer-term average levels? Not clear why you don't want to simply take the audio out of the computer?

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 05, 2017, 12:41:52 am
content: I'm pretty sure "audio level data" is the RMS of the audio over a 100ms or so period.

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 05, 2017, 05:23:41 am
content: Quote from: NiHaoMike on November 05, 2017, 12:41:52 amYes, of course. I just wasn't sure which emoticon symbolizes a rhetorical question.Expecting to find a built-in function to take the envelope of the audio signal, integrated over some unstated time period and output digitally seems rather unlikely in any computer.

author: Alex
author_rank: Regular Contributor
timestamp: November 06, 2017, 02:33:38 pm
content: In this particular case what can be done will drive the application; I appreciate the comments on ambiguity.I am not looking for complexity beyond a simple visual effect; something like the green bar behind the volume setpoint in Windows.There is already a virtual COM port to my device so it makes sense to try and send data over that, if possible.From Someone's comments I get the feeling that an existing plugin on an established media player might be possible, I will look into that.Alex

author: ogden
author_rank: Super Contributor
timestamp: November 06, 2017, 02:57:55 pm
content: Quote from: Alex on November 06, 2017, 02:33:38 pmWhat you need - VU meter PC software with remote display capability. Arduino will act as VU display which shows received over serial port, VU level. You could add com port support to project like this and with little coding on arduino side you are done:https://www.codeproject.com/Articles/94567/Logarithmic-PPM-sound-meters This one is even closer to the subject, just interface type and "remote display" differ:http://www.instructables.com/id/Parallel-port-based-VU-Meter/