3D Printing Custom LED Bar Graphs

[BikerGlen] wanted to spice up his zombie containment unit (see video below) so he designed and 3D printed some very cool looking bar graphs. Apparently, you can get curved bar graph LEDs, but only if you buy a fairly large quantity. Hand soldering discrete LEDs at the perfect angle would be frustrating, but with a 3D printed jig, it was a piece of cake.

The devices use a MAX6954 LED driver, so it needs very few parts and takes commands via SPI. The chips were not cheap, but the small size and high integration sold [Glen] on it.

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A Very Large VU Meter Indeed

It used to be a must-have on any hi-fi, a pair of moving coil meters or LED bar graphs, the VU meter. Your 1980s boombox would have had them, for example. VU, for “Volume Units”, is a measure of audio level, and the fashion for its visual measure in consumer audio equipment seems now to have largely passed.

The LED bar graph VU meters were invariably driven by the LM3915, a chip that contains a resistor ladder and a stack of comparators which can drive LEDs directly. [Juvar] has taken an LM3915, and used it to drive a set of opto-isolated triacs which in turn drive a stack of appropriately coloured mains LED bulbs concealed within an Ikea Vidja lamp. The result is a huge and very bright VU meter that is as much a lighting effect as it is a measure of sound level.

He’s posted a video of the lights in action, and we’ve placed it below the break. There is a cameo appearance from his cat, and one can’t escape the feeling that it is wasted on a small room and would be at its best before a dance floor. Still, it’s a neat lighting effect and a new use for a classic integrated circuit.

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Hackaday Prize Entry: Modular Rail Lighting

When operating any kind of hydroponic farming, there are a number of lighting solutions — few of them inexpensive. Originally looking for an alternative to the lighting of IKEA’s expensive hydroponics system, [Professor Fartsparkle] and their colleague prototyped a rail system that allows clip-on LED boards for variable lighting options.

Taking inspiration from wire and track lighting systems, the key was the 5mm fuse holders mounted on the bottom of the LED boards. Snipping off their stopping clip makes them easy to install and remove from the mounting rails. The rails themselves double as power conduits for the LED boards, but keeping them out of the way is easily done with the variety of 3D printed hangers [Professor Fartsparkle] has devised. Lighting is controlled by a potentiometer on the power injection board, as well as any home automation control via an ESP8266.

[Professor Fartsparkle] asserts that the boards can be slid along the rails without any noticeable flickering, but they do suffer from heat dissipation issues. That aside, the prototype works well enough that the 3W LEDs can be run at half power.

This is an ingenious — and cheap — workaround for when sunlight isn’t an option, but you are still looking for a solution capable of automation.

A Smart Table For Gamers

When makers take to designing furniture for their own home, the results are spectacular. For their senior design project, [Phillip Murphy] and his teammates set about building a smart table from the ground up. Oh, and you can also use it to play games, demonstrated in the video below.

The table uses 512 WS2812 pixels in a 32 x 16 array which has enough resolution to play a selection of integrated games — Go, 2-player Tetris, and Tron light cycle combat — as well as some other features like a dancing bird party mode — because what’s the point of having a smart table if it can’t also double as rave lighting?

A C2000-family microcontroller on a custom board is the brains, and is controlled by an Android app via Bluetooth RN-42 modules. The table frame was designed in Sketchup, laser-cut, and painstakingly stained. [Murphy] and company used aluminum ducting tape in each of the ‘pixels’, and the table’s frame actually forms the pixel grid. Check out the overview and some of the games in action after the break.

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Hackaday Prize Entry: Brightenmacher

We have all at some point have made a flashlight. It used to be a staple of childhood electronics, the screw-in bulb in a holder, and a cycle lamp battery. If you were a particularly accomplished youthful hacker you might even have fitted a proper switch, otherwise, you probably made do with a bent paperclip and a drawing pin.

So you might think that flashlights offer no challenges, after all, how many ways can you connect a bulb or an LED to a battery? [Peter Fröhlich] though has a project that should put those thoughts out of your mind. It uses a power LED driven by a TI TPS61165 boost driver, with an ATTiny44 microcontroller providing control, battery sensing, and button interface. The result is a dimmable flashlight in a 3D printed case housing both control circuitry and a single 18650 cell which he sourced from a dead laptop. Suddenly that bent paperclip doesn’t cut it anymore.

The result is a flashlight that is the equal of any commercial offering, and quite possibly better than most of them. You can build one yourself, given that he’s published the physical files necessary, but probably because this is a work in progress there are as yet no software files.

We’ve featured a lot of flashlights over the years, but it’s fair to say they usually tend towards the more powerful. Back in 2015 we published a round-up of flashlight projects if it’s a subject that captures your interest.


Ask Hackaday: What About the Diffusers?

Blinky LED projects: we just can’t get enough of them. But anyone who’s stared a WS2812 straight in the face knows that the secret sauce that takes a good LED project and makes it great is the diffuser. Without a diffuser, colors don’t blend and LEDs are just tiny, blinding points of light. The ideal diffuser scrambles the photons around and spreads them out between LED and your eye, so that you can’t tell exactly where they originated.

We’re going to try to pay the diffuser its due, and hopefully you’ll get some inspiration for your next project from scrolling through what we found. But this is an “Ask Hacakday”, so here’s the question up front: what awesome LED diffusion tricks are we missing, what’s your favorite, and why?

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Hackaday Prize Entry: Portable LED Flash For Photography

Photography is all about light. It’s literally right there in the name – stemming from the Greek word, photos. This is why photographers obsess over the time of day of a shoot, why Instagrammers coalesce around landmarks at sunset, and why a flash helps you take photos in darkness. Historically, flashes have worked in all manner of ways – using burning magnesium or xenon lamps for example. For this Hackaday Prize entry, [Yann Guidon] is developing a portable flash using LEDs instead.

By this point in time, you might be familiar with LEDs as flash units from your cellphone. However, [Yann] is taking this up a notch. The build is based around 100W LED modules, which obviously can pump out a lot of light. The interesting part of the build is its dual nature. The LEDs are intended to operate in one of two ways. The first is in a continuous lighting mode, running the modules well below their rated power to reduce the stress on the LEDs and power supply, and to enable the flash to run on the order of an hour. In this mode, temperature feedback will be used to control the LEDs to manage power use. The other is a pulsed mode, where the LED will be overvolted for a period of milliseconds to create a much more powerful flash.

It’s this dual nature which gives the LED-based flash a potential advantage over less versatile xenon-based units, which are limited to pulsed operation only. We can see the continuous lighting mode being particularly useful for videographers needing a compact, cheap lighting solution that can also work as a pulsed unit as well.We’re excited to see how [Yann] tackles the packaging, thermal and control issues as this project develops!