This Big, Bright Seven-Segment Display Is 3D-Printable

March 18, 2018 by Dan Maloney 16 Comments

Seven-segment LED displays have been around forever, it seems, and the design is pretty optimized by now. Off-the-shelf units are readily available in all sorts of sizes and colors, but if you want a really big display, you might have to roll your own. Scaling up the size doesn’t necessarily mean you have to scale up the complexity, though, if this light-pipeless jumbo seven-segment LED display is any indication.

It’s clear that [Fran Blanche] has a thing for collecting and building oddball numeric displays, like this cathode ray tube Nixie knockoff or her Apollo DSKY electroluminescent display. Her plus-size seven-segment display is far less complicated than either of those, and that’s by design; [Fran] wanted something that was 3D-printable as a single part, rather than an assembly with light pipes and diffusers. To that end, the display is just a pair of X-shaped dividers stacked on top of each other behind the display’s face. They dividers form six triangular compartments and a diamond shaped one, with each compartment opening into a segment-shaped window. One LED goes in each triangular compartment, while the double-sized diamond space gets two. That’s it — the LEDs light up the inside of each compartment to turn on the appropriate segments. Watch it in action below.

The display still needs some tweaking, but it’s big and bright and has a large acceptance angle. What’s more, it’s scalable — imagine a display the size of a sheet of plywood using LED light bulbs. We’re looking forward to [Fran]’s improvements and her next display project, which appears to use hot glue as a light pipe.

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Lamp Analysis Tells Sad Truth Behind The Marketing Hype

January 13, 2018 by Dan Maloney 57 Comments

Here in the northern hemisphere, winter has wrapped us in her monochromatic prison. A solid deck of gray clouds means you need a clock to tell the difference between night and day, and by about the first week of February, it gets to feeling like you’ll never see a blue sky again. It’s depressing, to be honest, and the lack of sunlight can even lead to a mood disorder known as SAD, or seasonal affective disorder.

SAD therapy is deceptively simple — bright full-spectrum light, and lots of it, to simulate the sun and stimulate the lizard brain within us. Not surprisingly, such lights are available commercially, but when [Justin Lam] bought one to help with his Vancouver blues, he decided to analyze the lamp’s output to determine whether the $70 he spent paid for therapy or marketing.

The initial teardown was not encouraging, with what appeared to be a standard CFL “curly fry” light with a proprietary base in a fancy plastic enclosure. With access to a spectrometer, [Justin] confirmed that not only does the SAD light have exactly the same spectrum as a regular CFL, the diffuser touted to provide “full UV protection” does so simply by attenuating the entire spectrum evenly so that the UV exposure falls below the standards. In short, he found that the lamp was $70 worth of marketing wrapped around a $1.50 CFL. Caveat emptor.

Hats off to [Justin] for revealing the truth behind the hype, and here’s hoping he finds a way to ameliorate his current SAD situation. Perhaps one of these DIY lamps will be effective without the gouging.

Transparent 3D Printing?

May 13, 2017 by Al Williams 12 Comments

Transparent plastic is nothing new. However, 3D prints are usually opaque or–at best–translucent. [Thomas Sanladerer] wanted to print something really transparent. He noticed that Colorfabb had an article about printing transparent pieces with their HT filament. [Thomas] wanted to try doing the same thing with standard (and cheaper) PETG, which is chemically similar to the HT. Did he succeed? Watch the video below and find out.

You can get lots of clear plastic filament, but the process of printing layers makes the transparency turn cloudy, apparently mostly due to the small gaps between the layers. The idea with the HT filament is to overextrude at a high enough temperature that the layers can fuse together.

[Thomas] wanted to create some clear parts and diffusers for lamps. The diffusers print using vase mode and the lamps he creates when them look great even without clear diffusers.

His first experiments involved layer height and extrusion rates. He tried to determine what was making things better and worse and modifying his technique based on that. There were also some post-processing steps he tried.

If you want to see what the Colorfabb HT parts made by someone other than Colorfabb look like, check out the second video below from [3D Printing Professor]. The prints he is making don’t look very clear until he does some post processing. Even after the post processing, it isn’t going to fool anyone into thinking it is glass-clear. However, the parts that Colorfabb shows on their blog post about the material do look amazing. Between the overextrusion used to prevent gaps and the post processing steps, [3D Printing Professor] warns that it won’t be easy to get parts with precise dimensions using this technique.

If you have a big budget, you could try printing with actual glass. There seem to be several ways to do that.

Ask Hackaday: What About The Diffusers?

April 25, 2017 by Elliot Williams 82 Comments

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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Sleek Desk Lamp Changes Colors Based On Sun Position

December 13, 2014 by Rick Osgood 9 Comments

[Connor] was working on a project for his college manufacturing class when he came up with the idea for this sleek desk lamp. As a college student, he’s not fond of having his papers glowing brightly in front of him at night. This lamp takes care of the problem by adjusting the color temperature based on the position of the sun. It also contains a capacitive touch sensor to adjust the brightness without the need for buttons with moving parts.

The base is made from two sheets of aluminum and a bar of aluminum. These were cut and milled to the final shape. [Connor] found a nice DC barrel jack from Jameco that fits nicely with this design. The head of the lamp was made from another piece of aluminum bar stock. All of the aluminum pieces are held together with brass screws.

A slot was milled out of the bottom of the head-piece to make room for an LED strip and a piece of 1/8″ acrylic. This piece of acrylic acts as a light diffuser. Another piece of acrylic was cut and added to the bottom of the base of the lamp. This makes for a nice glowing outline around the bottom that gives it an almost futuristic look.

The capacitive touch sensor is a pretty simple circuit. [Connor] used the Arduino capacitive touch sensor library to make his life a bit easier. The electronic circuit really only requires a single resistor between two Arduino pins. One of the pins is also attached to the aluminum body of the lamp. Now simply touching the lamp body allows [Connor] to adjust the brightness of the lamp.

[Connor] ended up using an Electric Imp to track the sun. The Imp uses the wunderground API to connect to the weather site and track the sun’s location. In the earlier parts of the day, the LED colors are cooler and have more blues. In the evening when the sun is setting or has already set, the lights turn more red and warm. This is easier on the eyes when you are hunched over your desk studying for your next exam. The end result is not only functional, but also looks like something you might find at that fancy gadget store in your local shopping mall.

Halloween Props: Spooky Eyes Light Up The Bushes

October 19, 2012 by Mike Szczys 11 Comments

This is just one example of several pairs of spooky eyes which light up [Vato Supreme’s] bushes this Halloween. The quick and inexpensive build process make it a perfect diy decoration.

Each eye is made up of a ping-pong ball and an LED. But that alone won’t be very spook as the entire ball will glow rather brightly. So he spiced things up a bit by masking off the shape of a pupil and spraying the balls black. The vertical slit seen in white above will glow red like a demon in the night.

The LEDs are driven by an ATtiny85 running the Arduino bootloader. [Vato] found there was plenty of space two write code which fades the eyes in and out using PWM. This happens at random intervals for each of the four pairs he is driving.

We’ve seen a similar project that used oversized LEDs as the eyes. But we really like the idea of using a diffuser like this one. See it in action after the break.

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A Much Larger Rainbow Board Of Many Ping Pongs

July 27, 2012 by Mike Szczys 11 Comments

[George] started with an 8×8 grid, but just couldn’t help himself from upscaling to this 32×16 pixel ping pong ball display. That’s right, It’s a 512 pixel array of fully addressable RGB LEDs diffused with one ping pong ball each.

We featured the predecessor to this project back in January. That one was an 8×8 display using a Rainbowduino as the controller. [George] took what he learned from that build and expanded upon it. The larger display is modular. Each module starts as an 8×8 grid which connects back to the Arduino using a breakout shield with some Ethernet jacks used as quick connects. The LEDs are driven by 595 shift registers, with transistors which protect the logic chips from the currents being switched.

He had a lot of help soldering all the connections for the display and ended up bringing it to show off at the Manchester mini maker faire. See it in action in the video after the break.

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