Edge-Lit Ping Pong Paddle Lights Up The Fight

December 13, 2019 by Kristina Panos 7 Comments

[George] and his coworkers like to blow off a little lunchtime steam on the company ping pong table. We might do the same, except it’d just be us versus the wall, and most of the exercise would consist of bending over to pick the ball up off the floor. When he found a scrap piece of acrylic out in their shop, [George] got the bright idea to make an edge-lit paddle featuring the company’s logo.

Not only does the paddle look cool, it works pretty well, too, even though it’s heavier and has smooth surfaces compared to a standard paddle. To begin, [George] found a regulation-size paddle outline and imported it into SolidWorks, then designed all the necessary cuts for the LEDs and other electronics. He also designed and printed ergonomic grips to protect the goods.

Continuing the stuff-on-hand theme, [George] used through-hole LEDs and dug into the abundance of battery clips and springs they have lying around for designing prototypes, instead of making it all fancy with SMT LEDs and a rechargeable battery pack. Slip on those sweatbands, because we’re serving up the build video after the break.

We see more ping pong balls than paddles around here, and that’s probably because they make great LED diffusers.

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Reverse Engineering An Old Bus Display

December 11, 2019 by Tom Nardi 14 Comments

When his makerspace was gifted a pair of Luminator LED signs of the sort you might see on the front of a bus, [PWalsh] decided to pull one apart to see what made it tick. Along the way, he managed to reverse engineer its control protocol and replace its original control board with a WiFi-connected Raspberry Pi. Now they can use the LED signs to show whatever they want; no bus required.

As they were designed for automotive use, the signs were wired for 12 volts DC. So the first order of business was fitting it with an AC/DC converter so it could be plugged into the wall. After he measured the display’s current consumption, [PWalsh] estimated it’s maximum energy consumption and determined an old ATX computer power supply was more than up to the task.

With the sign happily running battery-free, he could begin figuring out how to talk to it. Noticing a MAX485 RS-485 converter on the PCB, gave a pretty good idea of what language it was speaking, and with the aid of his trusty oscilloscope, he was able to suss out the baud rate. A cheap USB to RS-485 converter was then wired in between the sign and its control board so he could sniff the data passing over the line.

From there, the final piece of the puzzle was studying the captured data and figuring out the protocol. [PWalsh] was able to identify packet headers and ASCII characters, and pretty soon knew enough about how the sign communicated that he was able to remove the control board entirely and just push text and images to it right from the Pi. He’s even made his framework available for anyone else who might have a similar piece of bus-signage laying around.

Even if you’re not looking to add one of these signs to your lab, this project is a fantastic example of protocol reverse engineering with low-cost tools and simple techniques. We always love to see the process broken down step by step like this, and our hat’s off to [PWalsh] for delivering the goods in a big way.

This isn’t the first time we’ve seen these sort of LED signs get the “Internet of Things” treatment, and if you’re content with a somewhat scaled down version, you could always just build your own display rather than waiting on the local public transit vehicle to get parted out.

Angela Sheehan Is Developing Wearable Tech With Whimsy

December 11, 2019 by Tom Nardi 4 Comments

As a concept, wearable technology excites many of us, but in practice, it’s been hard to nail down. Up to this point, the most high-tech thing the average person might reasonably wear has been a wrist watch. Devices like Google Glass tried to push the state-of-the-art, but it arguably raised more questions than it answered. It demonstrated in a very public way that developing wearable technology that’s simultaneously visually appealing, useful, and robust enough to handle daily life is exceptionally difficult. If Google couldn’t pull it off, what hope do we lowly hackers have?

But maybe we’ve been going about things the wrong way. Compelling as the end result may seem, the move from wrist watches to head-mounted computers is simply too large of a technical and psychological leap to make. To help develop the skills and techniques necessary to build practical wearable electronics, it might help to take a slightly more fanciful approach.

It seems to be working pretty well for Angela Sheehan, at least. In her talk “Building Whimsical Wearables: Leveling Up Through Playful Prototyping” at the 2019 Hackaday Superconference, she went over some of the things she’s learned while developing her Color Stealing Fairy costume. The product of several years of iterative design, the costume is able to mimic colors seen in the environment through the use of a wireless sensor wand, and features a number of design elements that are critical to any successful wearable project.

Even if a custom RGB Fairy costume isn’t on your short list of projects, there’s information in this talk that will surely be of interest to anyone who’s even contemplated a wearable project. From technical aspects like battery placement to logistical considerations such as making adjustments for multiple wearers, Angela’s make-believe creation has become a testbed for real-world considerations.

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A Tree Of LEDs That Blows Out Like A Candle

December 11, 2019 by Donald Papp 14 Comments

The beautiful workmanship in [Andrew]’s LED tree is gorgeous all on its own, but of course there’s more going on than meets the eye. This LED tree can be blown out like a candle and it even playfully challenges a user to blow out all the lights at once in a single breath.

Some of you may remember the fascinating example of an LED you can blow out like a candle which had the trick of using the LED itself as a sensor. Like any diode, the voltage drop across the LED changes very slightly based on temperature. By minimizing thermal mass with surface-mount LEDs and whisker-thin wires, it was possible to detect when the LED was being blown on.

The LED tree shown here uses the same basic principle, but with a few important changes. The electronics have been redesigned and improved, and the Arduino used in the original proof of concept is ditched for stacked custom PCBs. Each board has a diameter under 100 mm in order to take advantage of the fab house’s lower cost for small boards. [Andrew] says that while the boards required a lot of time-consuming hand soldering and assembly, the payoff was that five boards rang in at barely five dollars (plus shipping) and that’s hard to beat.

Watch the tree in action in the brief video embedded below.

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Chaining Together A 16×2 Bubble LED Display

December 10, 2019 by Tom Nardi 27 Comments

We’ve recently noticed an uptick of interest in so-called “bubble displays”: vintage alphanumeric LEDs which are probably best remembered as being used in watches and calculators before the LCD took over. Today they’re available as surplus or even salvage for literally pennies, but unfortunately they only provide four or five characters to work with. Or rather they did, until [sjm4306] built a board that chains them into a 16×2 array.

For the princely sum of 71 cents each, [sjm4306] picked up ten HPDL-1414 displays, each capable of showing four characters. He then designed a PCB that would accept eight of the displays at once, and even thought ahead to use headers so they could be pulled out and swapped as needed. Of course mounting them is only half the battle, you still need to drive the things.

Each display has its own dedicated driver chip on board, but trying to address each one individually would take far too many pins. So [sjm4306] opted to use a trio of 74HC595 shift registers, allowing him to toggle the three dozen pins necessary over SPI from a microcontroller. He’s even written up a little library and some example code that you can grab on the project’s Hackaday.io page.

Unfortunately, after all his hard work, tragedy struck. As these displays were a couple decades old given their date code, [sjm4306] thought he would clean them up with a bit of alcohol before their big video debut. But whatever plastic the clear panels are made of didn’t take kindly to the IPA, and they all shattered. They still work, but it’s definitely a quirk to keep in mind if you pick up some of these vintage displays to play with yourself.

In the past we’ve seen a much smaller PCB that allowed similar displays to more easily be interfaced with modern microcontrollers; perfect if you just want to bang out a few retro LED characters with a minimum of fuss.

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Tuning Up The ThinkGeek Star Trek Intercom Panel

December 6, 2019 by Tom Nardi 8 Comments

On Star Trek, all Kirk and friends had to do was snap the button on the always conveniently located intercom panel, start talking, and the intended recipient would immediately respond no matter where they were in the ship. How did it work? Who knows. In spite of, or perhaps even because of, the lightly-explained nature of the technology, the cherry-red wall intercoms still hold a certain charm for fans of the groundbreaking show.

A viewer sent [Fran Blanche] a scaled down replica of the intercom from ThinkGeek, and while it certainly looks fairly close to the original prop, it has a couple of annoying design elements. When triggered by the side-mounted motion sensors, the panel will play either the iconic swoosh of the automatic doors or the “Red Alert” sound effect. It’s a cute idea for a kid’s bedroom maybe, but not exactly ideal for somebody who regularly records YouTube videos.

So the first order of business was to cut the motion sensors out of the circuit and replace them with a push button. [Fran] draws up a quick diagram to explain how these sensors work, and shows that they can easily be bypassed with a momentary switch since they normally bring the line high when triggered. She then converted the indicator light on the right side of the panel into a button to enable the alert sound effect, which is more accurate to how it worked in the show anyway.

The other issue, and perhaps the most egregious to Star Trek fans, is that the “Red Alert” indicator on the top of the panel didn’t actually flash like it did in the show. To design and build this panel and not put a few LEDs behind that piece of frosted plastic seems a bit like producing a Matchbox car and forgetting to make the wheels spin. With a couple of red LEDs and a bit of new wiring, the oversight was quickly rectified.

While it might not be perfect, at least ThinkGeek actually produced a functional product this time. It could have ended up like one of their April Fool’s “products” that never get put into production, forcing a desperate Trekkie to begrudgingly build his own version.

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Start Your Day With The Mountain That Rises

December 4, 2019 by Tom Nardi 3 Comments

Like many of us, [Zach Archer] enjoys the comfort of his darkened room so much that he has trouble getting up and facing the day. To make things a little easier for himself, he decided to put together a custom alarm clock that would fill his mornings with the glorious glow of LEDs; and since he finds the mountains an inspirational sight he decided to wrap the whole thing up in a 3D printed enclosure that resembles snow capped peaks.

But even Bob Ross himself couldn’t have imagined a snowy mountain range that featured an integrated e-ink screen. The big 4.2″ panel is connected to a custom designed PCB by [romkey], which was graciously donated for this project. An ESP32 runs the show, providing a convenient web interface to control not only the clock, but various aspects of the mountain’s internal LEDs such as fade in time and total duration.

[Zach] says he originally printed the mountains in PLA, but the heat generated by the LEDs eventually started to cause things to warp. Switching over to translucent PETG not only solved the heat problem, but made for a very effective LED diffuser. Rather than complex animation patterns, he’s found that smoothly transitioning between different shades of blue and green seems to work best for him in the mornings.

This isn’t the first time we’ve seen somebody use LEDs to get them out of bed in the morning, but we do appreciate the aesthetic that [Zach] has achieved here between the design of the mountains and the impressive artwork on the e-ink display. Then again, we’re also quite partial to this version that looks like a warp core, so our tastes do run the gamut.