VFD displays are beloved for their eerie glow that sits somewhere just off what you’d call blue. [mircemk] used one of these displays to create an old-school VU meter that looks straight out of a 1970s laboratory.
The build uses an Arduino Nano as the brains of the operation, which uses its analog inputs to process incoming audio into decibel levels for display on a VU meter. It’s then charged with driving a GP1287 VFD display. Unlike some VFDs that have preset segments that can be illuminated or switched off, this is a fully graphical dot matrix display that can be driven as desired. Thus, when it’s not acting as a bar graph VU meter, it can also emulate old-school moving-needle meters. Though, it bears noting, the slow updates the Arduino makes to the display means it’s kind of like those dodgy skeumorphic music apps of the 16-bit era; i.e. it’s quite visually jerky.
Overall, it’s a neat project that demonstrates how to work with audio, microcontrollers, and displays all in one. We’ve featured other projects from [mircemk] before, too, almost all of which appear in the same blue and grey project boxes. Video after the break.
Everybody keeps saying
VU meter
what does VU even stand for?
“Volume Unit” meter which is an indicator that displays the volume relative to a standard (“one unit”) volume level.
I thought this looked familiar… Lewin, I think you’re reposting old content!
March 9, 2022: VFD CHARACTER DISPLAY TURNED INTO AUDIO VU METER
https://hackaday.com/2022/03/09/vfd-character-display-turned-into-audio-vu-meter/
This is a dot matrix display; the article you linked to was a 2×20 character-style one. Same guy and it looks like he reused the case (or just made another identical one) but different display.
That looks more like a *simulated* (and a poor one at that) VFD.
You want authentic VFD, look at the “Telepost LP-100A” in line HF wattmeter.
I have one in my station, and the bright blue glow is unmistakeable.
I think it’s just the white balance of the camera not being right. The GP1287 is a true VFD and other pictures on the Internet shows a more bluish tone. Note that VFD’s do have a variety of color tones.
or the Kenwood TS-450/850/950 era.
Kenwood TS450 is a backlit LCD with numbers in “negative” and a color filter.
Your AI generated comment smells BS.
It IS a VFD display. Obviously you´ve seen them only behind a color filter.
Great journey and learnings to build a VU meter. A lot goes into these sorts of projects.
From a commercial perspective, nicest looking VU meter in a VFD I think is the long discontinued Squeezebox. See this image: https://the-gadgeteer.com/assets/slimdevices-squeezebox6.jpg This device may seem somewhat redundant with all the newer streaming stuff, but wow… when the SqueezeServer does get turned down, we have to come up with an alternate use for this VFD.
Whoever coded the meters in Audacity gets the prize. 4 factors are displayed not just the one, all in the same space. The standard for audio instrumentation. The meter here has no pips lined up with the numbers and +3 dB does not happen in digital audio. That belonged to the era of tape and vinyl but not radio.
https://service.shure.com/s/article/is-there-a-difference-between-a-vu-and-a-ppm-audio-meter?language=en_US
The project is cool, but an average-reading VU meter has little application these days, besides blinkenlights for a stereo system. I’m a sucker for real moving-needle VU meter movements, and I have maybe 16 to 20 VU meters (separately, or as part of analog recorders and mixers). Very retro.
Shouldn’t the channel input grounds go to the circuit ground? Perhaps with additional isolation components?
Correct. The schematic has been faulty since the first iteration of this setup (then it was 2×40 LCD wit HD44780 controller) – It persists.