Collection of Nixie bar graphs bump to the beat

This VU meter uses Nixie tubes as the display. There are a total of fourteen IN-13 bar graph tubes that map out the audio spectrum. The build uses purely hardware for the display; no microcontroller processing, or dedicated VU-meter chips were used.

Input begins with a dual Op-Amp along with a pair of potentiometers which allow the left and right channels to be balanced. Both channels are then each split into seven signals, which explains the layout of tubes seen above. Each signal is then fed through a voltage divider to envelope the output between 0V and 6V. There is also a low-pass filter to handle sudden volume spikes which don’t work well with the nixies. But as shown in the video after the break, all that work has paid off. Thr clip gives us a look at the green protoboards which host all of this filtering hardware. You’ll want to turn the volume down for the first couple of demonstrations which use a sweep to test the system.

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The Ultimate Breadboard – a prototyping station that has it all


[Claudio] was working on a homebrew oscilloscope project when he started thinking about how unsuitable a standard breadboard is for a large-scale project. Rather than adding components on top of components until they became what he lovingly calls a “fragile, unforgiving crapstack”, he decided to build himself the Ultimate Breadboard.

He packed so much into his design, that it’s honestly hard to know where to begin describing it. Aside from an appropriately large breadboarding surface embedded in the center of the console, he added a power supply to the left hand side, which sits just below an Avr-Net-IO board. The right side of the console features an Arduino NG, and a pair of level converters. He also added some LED-based VU meters, a couple of 7-segment displays, an LCD display, an analog voltmeter, along with plenty of I/O connectors.

The Ultimate Breadboard might look a bit daunting at first, but it seems like an awesome setup on which to do any sort of prototyping. Be sure to check out the video below for more details and to see [Claudio] give a tour of the device.

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A quick and dirty VU meter for your next party

If you want an easy project to spice up your next party, chances are you already have parts on hand to throw together [Mikerbot's] quick and dirty VU-meter lights. The circuit he designed uses the audio input to trigger the base of a PNP transistor, toggling power through a string of LEDs. He’s using four lights for each of the stereo output signals, making them pulse with the music as seen in the video after the break. The circuit is built on a breadboard, and housed in a picture frame with a less-than-impressive diffuser (we think that’s always the hardest part… check out the Heavy Frost used in this project if you want something that works really well).

There are some VU meter chips out there that will really augment this concept. But one improvement might be to throw in an amplifier chip like the LM386 and a couple of potentiometers so that you can dial-in the sensitivity.

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Using an LED cube as an audio visualizer

[Isaac] sent in his mashup build of a LED cube combined with a graphic EQ meter. The build is fairly simple and from the video we can tell that his build would be a great installation in a dubstep venue. While it’s not the 9x9x9 cube possible with some judicious coding we think it’s a very fitting display for the intended purpose.

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VU meter scarf lights up the night


[Eli Skipp] wrote in to share a project she has been working on bit by bit, for over a year – an LED VU meter scarf. The project was originally going to be built using a custom PCB, but no matter how long she spent troubleshooting the piece, it just wouldn’t work right. She eventually broke down and purchased a VU meter kit, which worked out quite a bit better than the homebrew version.

The VU meter circuitry is tucked away inside the scarf as she shows in the video below. The LEDs are connected using conductive thread sourced from Lamé Lifesaver, which she says is far more durable than other threads she has tried. After originally testing the VU meter, she was unimpressed by the output of the LEDs, so she swapped them out for brighter ones, which look much better. It looks like it works quite well – we definitely dig the idea of a scarf with a built-in VU meter, even if it was partially built from a kit.

Continue reading to see [Eli] give a quick demonstration and a rundown of the scarf’s construction.

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VU meter lives in a Linksys housing

[Dillon] just finished his first project of the summer. It’s a volume units meter for his sound system and it has a few tricks up its sleeve.

He’s driving the rows of LEDs using an AN6884 LED driver chip. It has an integrated amplifier circuit which makes it the perfect part for building a VU display. He had a broken Linksys 5-port switch sitting around which he used as the enclosure for the project. It has just enough room to incorporate a speaker in case he wants to take the meter on the road with him. But when at home he can choose to use his stereo system instead with the flip of a switch. To ensure he’s making the most out of the 5-bit precision he’s included a voltage divider that can be adjusted with a potentiometer. We’ve embedded a video after the break which shows how well it works.

Looking for a bit more inspiration for your own VU meter project? Check out this RGB version.

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RGB VU meter

[Simon Inns] turned out this VU meter with a 16 RGB LEDs. He’s using three 16-bit TLC5940NTG LED drivers for the project. They’re not cheap chips but they do a great job. If you were looking to save on parts [Simon] found there’s more than enough brightness and any loss due to multiplexing would not be a problem. The device connects to a computer via USB thanks to the PIC 18F2550 which he’s used in his past VU meter projects. One of the design choices he made was to use a switching power supply. The LM2576 (datasheet) has no problem sourcing 3A at 5V and in addition to two electrolytic capacitors which are commonly used with linear regulators, you just need to add a diode and an inductor.

The meter offers several different configurations which are set on the PC side of things. These include the colors that are used and if the entire bars is used as one meter or split into sections to display both audio channels. Check it out after the break.

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