Triangle Tiles Form Blinky Networks Using Clever Interconnects

June 7, 2021 by Kerry Scharfglass 14 Comments

We love to see LEDs combined in all shapes and sizes, so we were especially ticked when we caught a glimpse of [Debra Ansell]’s (also known as [GeekMomProjects]) interlocking triangular TriangleLightPanel system glowing on our screen. This unusually shaped array seemed to be self supporting and brightly glowing, so we had to know more.

The TriangleLightPanel is a single, triangular, light panel (refreshing when everything is in the name, isn’t it?). Each panel consists of a single white PCBA holding three side-firing SK6812 LEDs aimed inward, covered by transparent acrylic. When the LEDs are doing their thing, the three-position arrangement and reflective PCB surface does diffuses the light sufficiently to illuminate each pane — if not perfectly evenly — very effectively. Given the simple construction it’s difficult to imagine how they could be significantly improved.

The real trick is the mechanical arrangement. Instead of being connected with classic Dupont jumper wires and 0.1″ headers or some sort of edge connector, [Debra] used spring contacts. But if you’re confused by the lack of edge-plated fingers think again; the connectors are simple plated strips on the back. There is a second PCBA which effectively acts as wires and a surface to mount the spring contacts on, which is bolted onto the back of the connected leaves to bridge between each node. The tiles need to be mechanically connected in any case, so it’s a brilliantly simple way to integrate the electrical connection with the necessary mechanical one.

All the requisite source files are available on the project’s GitHub page and the original Tweets announcing the project are here for reference. We can’t wait to see what this would look like with another 30 or 40 nodes! Enterprising hackers are already building their own setup; see [arturo182]’s 24 tile array glowing after the break.

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Investigating A New Chip In A Minimalist LED Lamp

May 27, 2021 by Danie Conradie 6 Comments

Teardowns of cheap electronic devices can produce results that are interesting, horrifying, or both, especially when mains power is involved. [bigclivedotcom] gave a minimalist LED lamp his reverse engineering treatment, and discovered a new chip that requires only four additional passive components to run LEDs on AC power.

The chip in question is a Joulewatt JWB1981, for which no datasheet is available on the internet. However, there is a datasheet for the JW1981, which is a linear LED driver. After reverse-engineering the PCB, [bigclivedotcom] concluded that the JWB1981 must include an onboard bridge rectifier. The only other components on the board are three resistors, a capacitor, and LEDs. The first resistor limits the inrush current to the large smoothing capacitor. The second resistor is to discharge the capacitor, while the final resistor sets the current output of the regulator.

It is possible to eliminate the smoothing capacitor and discharge resistor, as other LED circuits have done, which also allow the light to be dimmable. However, this results in a very annoying flicker of the LEDs at the AC frequency, especially at low brightness settings.

As always, this is a very informative video from [bigclivedotcom], and it was all done based on a single picture of the PCB sent in by a viewer. He also mentions that the lifespan of the lamp would likely be increased by swapping out the current setting resistor for a larger one.

We’ve covered several [bigclivedotcom]’s videos, covering topics from self-powered wireless switches to filling up fake capacitors with electrolyte.

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Voidstar’s Vitals, Visualized For Video

May 26, 2021 by Kristina Panos 4 Comments

Great news for fans of [Voidstar Labs] — [Zack] is going to be streaming future builds live on YouTube instead of trying to keep up with a grueling and limiting schedule of releasing a build video every week. The only problem is that the wall behind him is totally blank and boring, which matters quite a bit for pretty much any streamer that doesn’t broadcast from a hot tub. Well, not anymore! Now the wall has twenty square feet of rainbow hexagons, because blinkenlights.

But these aren’t just any blinkenlights. They’re informative. They dance to the beat of [Zack]’s bio-metrics, or in other words, they are visualizing how sweaty and anxious [Zack] may be at a given moment, and turning that information into art.

At the heart of this build is a brand-new bio-metric board called the EmotiBit which boasts sixteen sensors in a small package, including a pulse oximeter. The EmotiBit sends vitals to [Zack]’s PC, which is running an oscilloscope app to interpret the signals. Then they are sent over Open Sound Control to an ESP32, which runs the light show.

Like [Zack] says in the video after the break, this isn’t a terribly difficult project, but the construction takes time. [Zack] used aluminum extrusion meant for under-cabinet lighting and ran forty strips of fourteen DotStar LEDs each. The nodes are printed in carbon-fiber PLA and hold the lights away from the wall so it looks cooler. Worried about the current draw? It’s okay, because the brightness and number of lit LEDs at any one time is limited. Add in the fact that none of the LEDs are ever turned off — they fade by one percent each loop — and you have some really cool animations. Check them out after the break.

Want some localized blinkenlights to wear about town? Wear your heart on your sleeve and show them how hard you’re crushing the elliptical at the gym.

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NeoPill Is The NeoPixel Emulator You’ve Always Wanted

May 26, 2021 by Lewin Day 16 Comments

NeoPixels and other addressable LED strings are a technology that have made vibrant, glowing LED projects accessible to all. Of course, it’s nice to be able to simulate your new glowy project in software before you actually set up your LED strings in practice. [Randy Elwin]’s NeoPill simulator can help with that!

The NeoPill consists of an STM32F103 development board, into which one simply hooks up a NeoPixel data line. The microcontroller then decodes the data using a combination of its onboard timers and SPI hardware. This data is then passed to a PC over the onboard USB serial connection, where it’s decoded by a custom Python app. The app takes the data and displays the pixels on screen, so you can verify they operate as expected before you hook up a single real LED.

It’s a great tool, one that costs very little and yet does the job well. It can even be used with LEDs in circuit to verify if problems are related to the data output or the hardware itself. [Randy] demonstrates the software working with strings of up to 256 LEDs at once; we’d love to see how far it can be pushed before breaking. Code is available on Github for those keen to get their own NeoPill operational.

It’s not the only NeoPixel simulator out there, but it is the first one we’ve seen that can be used to debug actual signals from real hardware, and that’s an incredibly useful thing to have in your toolbelt. Video after the break.

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Putting LEDs In Motorcyle Tail Light Shows How Trivial Becomes Tough

May 25, 2021 by Donald Papp 55 Comments

[Maarten Tromp]’s replacement of his motorcycle’s tail light with LED equivalents is a great example of something that every hacker learns sooner or later: interfacing to and working around existing parts can turn a trivial-seeming task into a much bigger job than expected. The more one has to work within the constraints of an existing system, the more opportunities there are for roadblocks and surprise issues to stall progress, and this project is a great example of that.

[Maarten]’s 1999 Honda ST1100 Pan European motorcycle had no aftermarket options for an LED rear light assembly, and he wasn’t too keen on just installing a generic module to replace the original. Instead, he resolved to purchase and disassemble a used factory assembly, and replace the incandescent lamps with some equivalent LEDs. Replacing bulbs with LEDs sounds easy, but doing the job right took [Maarten] almost two weeks in the end.

Problems started early with simple things like how to open up the light assembly itself. The unit isn’t user-serviceable and isn’t intended to be opened, and the parts are sealed shut with a waxy substance. Fortunately, heat does the trick. Another early hitch was the curved base of the light assembly, which made mounting flat perfboard or veroboard a challenge. In the end, [Maarten] settled on a triangular grid of high-brightness LEDs, driven with LM317 regulators configured as constant-current supplies, mounted on some protoboard cut to fit the unique curve of the assembly. The result accepts the wide voltage range of the motorcycle’s battery (from 10.5 V to 14.5 V) and can still function even if some individual LEDs stop working.

The project has one more example of how working around existing hardware can be a pain. [Maarten] had originally intended to swap out the turn signal lamps for LEDs as well, but there is a glitch. The motorcycle’s turn signal relay will do a fast blink pattern if burnt-out turn signal lamps are detected. Since LEDs consume considerably less current than the original bulbs, the relay will remain stuck in the fault condition. There are a few different ways around this, but it’s a problem for another day. For now, the tail light LED replacement is a success.

Working around existing hardware frequently brings unexpected challenges, but when safety systems (such as lights on a vehicle) are involved, it’s extra-important to make sure things are done right.

Persistent Displays With UV Light

May 24, 2021 by Jenny List 52 Comments

This year’s Hackaday Prize has “Rethink Displays” as one of its first theme, and [Tucker Shannon] has given us his best shot on that subject with a set of impressive displays that “write” on glow-in-the-dark material using ultra-violet light. These materials glow for a while after UV illumination, so moving a light source like a UV LED over the surface draws glowing text or simple graphics which can be readily consumed.

One of the examples this a clock we were first smitten with back in 2018. It is a rather attractive 3D-printed affair with those servos mounted below the screen that moves a UV LED through a pair of linkages. Other offerings that play on the same UV stylus medium include a laser on an az-el mount controlled by a Raspberry Pi Zero. It’s a neat idea very effectively done, and we can see it has a lot of potential.

But the most impressively advanced so far is the model shown in the image at the top of the article and the demo video at the bottom. A loop of phosphorescent material is the display surface itself. This one moves that loop with two rollers to make up the X axis, and moves the UV source up and down for the Y axis. As with all of these designs, whatever is written will soon fade, leaving the surface ready for the next bit of information.

Interested in this project and think you could do a display of your own? The Hackaday Prize 2021 is live, and we’d love to see you enter it!

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RGB LED Rings Teach Old Dash New Tricks

April 29, 2021 by Tom Nardi 9 Comments

We’ve seen several so-called “digital dash” upgrades over the years that either augment, or completely replace, a vehicle’s original dashboard indicators with new displays. Whether its seven segment LEDs or a full-on graphical interface powered by the Raspberry Pi, the end result is the same: a dashboard that looks wildly different than it did when the car rolled off the assembly line.

But this LED dashboard project from [Flyin’ Miata] takes a slightly different approach. Rather than replace the analog gauges entirely, rings of RGB LEDs of the same diameter were placed behind their matte black faces. When the LEDs are off you’d never notice them, but once they kick on, the light is clearly visible through the material.

LEDs can easily shine through the gauge face.

So far, it looks like most of the work seems to have been put into the tachometer. The firmware running on the CAN equipped Adafruit Feather M4 can do things such as light up a dynamic redline based on current engine temperature. It will also light up the LEDs to follow the analog gauge as it moves around, which might not have much practical application, but certainly looks cool.

On the speedometer side, the LEDs seem to be used primarily as warning indicators. As demonstrated in the video below, the whole gauge can light up bright red to indicate a critical situation such as low oil pressure. If you wanted to, the system could also be configured with different colors corresponding to various possible fault conditions.

Compared to some of the more aggressive dashboard updates we’ve seen, this is an interesting compromise that helps retain the look of the original instrumentation. Of course, depending on the make and model of the car, you might be able to sneak in a small LCD screen without anyone noticing.

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