ESP8266 Upgrade Gives IKEA LEDs UDP Superpowers

May 27, 2019 by Tom Nardi 39 Comments

It can be difficult to resist the impulse buy. You see something interesting, the price is right, and even though you know you should do your research first, you end up putting it in your cart anyway. That’s how [Tobias Girstmair] ended up being the not-so proud owner of a LEDBERG RGB LED strip from IKEA, and what eventually pushed him to replace wimpy original controller with an ESP8266.

So what was the problem with the original controller? If you can believe it, it was incapable of producing white light. When IKEA says an LED is multi-color, they apparently mean it’s only multi-color. A quick check of the reviews online seem to indicate that the white version is sold as a different SKU that apparently looks the same externally and has confused more than a few purchasers.

Rather than having to pick one or the other, [Tobias] decided he would replace the original controller with an ESP-03, hoping that would give him granular enough control over the LEDs to coax a suitably white light out of them. He didn’t want to completely start from scratch, so one of the first decisions he made was to reuse the existing PCB and MOSFETs. Some handy test points on the PCB allowed him to hook the digital pins of the ESP right to the red, blue, and green LED channels.

Then it was just a matter of coming up with the software. To keep things simple, [Tobias] decided to create a “dumb” controller that simply sets the LED color and intensity according to commands it receives over a simplified UDP protocol. Anything beyond that, such as randomized colors or special effects, is done with scripts that run on his computer and fire off the appropriate UDP commands. This also means he can manually control his newly upgraded LEDBERG strips from basically anything that can generate UDP packets, such as an application on his Android phone.

It might not be the most robust implementation we’ve ever seen, but all things considered, it looks as though this modification could be a pretty good way to get some cheap network controlled RGB lighting in your life.

Lateral Thinking For An Easier Charlieplex

May 20, 2019 by Kerry Scharfglass 9 Comments

In the practical world we live in, PCBs are often rectangles (or rectangles with rectangles, it’s just rectangles all the way down). When a designer goes to schematic capture things are put down on nice neat grid intersections; and if there isn’t a particular demand during layout the components probably go on a grid too. Routing even the nastiest fractal web of traces is mostly a matter of layers and patience. But if the layout isn’t being done in a CAD tool and needs to be hand assembled free-form this isn’t always as simple. [M Rule] had this very problem and discovered a clever solution, turning things diagonal.

They changed the fitness criteria to the optimization problem that is controlling a lot of LEDs. Instead of minimum pins to drive the goal became “easiest assembly”, which meant avoiding wires snaking back and forth across the layout, a big source of frustration in a big Charlieplexed design. The observation was that if they turned the a rectilinear LED matrix by 45° and wrapped each connection around at the edges it formed what was essentially a large multiplexed matrix. The topology is pretty mind bending, so take a minute to study the illustration and build your mental model.

It looks a little strange, but this display works the same way a normal multiplexed display does but with the added benefit that each trace flows from one side to the other without turning back on itself at any point. To light any LED set the right row/column pair as source/sink and it turns on!

What if you actually need a rectangular display? Well that’s no problem, the matrix can be bent and smooshed as desired to change its shape. At the most extreme the possible display topologies get pretty wild! We’re sure to try thinking laterally next time we need to design an unusual display, maybe there is a more efficient matrix to be found.

Not Happy With Smart Bulbs? Make Your Own

May 19, 2019 by Tom Nardi 23 Comments

The idea of the so-called “smart bulb” sounds good; who wouldn’t want to be able to verify the porch light is on if you’re out of town for the night, or check to see if you left the bathroom lights on in your rush out the door in the morning? But in practice, it can be a nightmare. Each brand wants to push their own protocol. Even worse, it seems you can’t get anything done without signing up for three different services, each with its own application that needs to be installed on your phone. It’s a frustrating and often expensive mire to find yourself in.

[Dom Gregori] liked the Hue bulbs offered by Philips, but didn’t want to buy into the whole ecosystem of phone apps and hardware hubs they require. So he decided to create his own open source version that would do everything he wanted, without any of the seemingly unavoidable baggage of the commercial offerings. The final result is a professional looking ESP8266 controlled RGB bulb that hooks into Home Assistant via MQTT.

Looking at his Bill of Materials, it’s actually pretty amazing to see how little it really takes to pull a project like this off. Outside of the Wemos D1 Mini board, [Dom] just needed a few concentric WS2812 rings, and a USB charger small enough to fit into the base of his 3D printed enclosure.

We especially like how he handled the socket-side of the bulb, as that’s the part that would have left us scratching our heads. Rather than trying to salvage the base from an existing bulb, or come up with his own printed piece to stick in the socket, he just used a cheap and readily available light socket adapter. The solution might be a little bulky, but we like how he’s deftly avoided having to handle any AC voltages in this project.

Over the last couple years, we’ve seen more and more smart bulb related content come our way. From the ever popular teardown of a new entry into the market to the sobering realization that your light bulbs might provide the key attackers need to access your network, it’s been fascinating to see the transformation of these once simple pieces of hardware into something far more complex.

DIY Button Matrix Lights Up And Speaks I2C

May 17, 2019 by Donald Papp 2 Comments

[David Johnson-Davies] always wanted an illuminated button matrix for projects, but cost was never very friendly. That all changed when he discovered a cheap source of illuminated pushbuttons on Aliexpress, leading to this DIY 4×4 illuminated button matrix design which communicates over I²C. The button states can be read independently of setting the light pattern, and an optional interrupt signal gets pulled low whenever there is a change detected. Not bad for one PCB plus about $10-worth in components!

The device uses every single pin on an ATtiny88, and because each button gets its own pin the keypresses can be detected with pin-change interrupts. The state reporting of buttons over I²C is unambiguous, even when multiple buttons are pressed simultaneously. A simple protocol provides all the needed functionality, and all connections are brought to the board’s edge to allow for easily tiling multiple panels.

The GitHub repository contains the code and PCB files and [David] helpfully shared the board files to OSH Park and PCBWay for easy ordering. In addition, he provides two demos (Tacoyaki and Tacoyaki+) which are games related to the classic Lights Out to show off the matrix.

A Ping Pong Ball LED Video Wall

May 17, 2019 by Dan Maloney 6 Comments

Constrained builds are often the most fun. Throw an artificial limit into the mix, like time limiting your effort or restricting yourself to what’s on hand, and there’s no telling what will happen.

[bitluni] actually chose both of those constraints for this ping pong ball LED video display, and the results are pretty cool, even if the journey was a little rough. It seems like using sheet steel for the support of his 15 x 20 Neopixel display was a mistake, at least in hindsight. A CNC router would probably have made the job of drilling 300 holes quite a bit easier, but when all you have is a hand drill and a time limit, you soldier on. Six strings of Neopixels fill the holes, a largish power supply provides the 18 or so amps needed, and an Arduino knock-off controls the display. The ping pong ball diffusers are a nice touch, even if punching holes in them cost [bitluni] a soldering iron tip or two. The display is shown in action in the video below, mostly with scrolling text. If we may make a modest suggestion, a game of Pong on a ping pong ball display might be fun.

[bitluni] says that the display is on its way to Maker Faire Berlin this weekend, so stop by and say hi. Maybe he’ll have some of his other cool builds too, like his Sony Watchman Game Boy mashup, or the electric scooter of questionable legality.

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An Impeccably Designed High-Speed LED Flash

May 16, 2019 by Tom Nardi 58 Comments

If you want to take a picture of something fast, and we mean really fast, you need to have a suitably rapid flash to illuminate it. A standard camera flash might be good enough to help capture kids running around the back yard at night, but it’s not going to do you much good if you’re trying to get a picture of a bullet shattering a piece of glass. For that you’ll need something that can produce microsecond flashes, allowing you to essentially “freeze” motion.

You can buy a flash that fast, but they aren’t common, and they certainly aren’t cheap. [td0g] thought he could improve on the situation by developing his own microsecond flash, and he was kind enough to not only share it with the world, but create a fantastically detailed write-up that takes us through the entire design and construction process. Even if you aren’t in the market for a hyper-fast flash for your camera, this is a fascinating look at how you can build an extremely specialized piece of gear out of relatively common hardware components.

So what goes into a fast LED flash? Rather unsurprisingly, the build starts with high-quality LEDs. After some research, [td0g] went with an even dozen CREE CXA2530 arrays at just shy of $7 USD each. Not exactly cheap, but luckily the rest of the hardware is pretty garden variety stuff, including a ATMega328P microcontroller, some MOSFETs, and a TC4452 driver. He did pack in some monstrous 400 V 10μf capacitors, but has since realized they were considerably overkill and says he would swap them out if doing it all over again.

To make development easier (and less costly, should anything go wrong), [td0g] designed the flash so that the LEDs are arranged in banks of three which can be easily removed or swapped in the 3D printed case. Each trio of LEDs is in a removable “sled” that also holds the corresponding capacitor and MOSFET. Then it was just a matter of getting the capacitors charged up and safely dumping their energy into the banks of LEDs without frying anything. Simple.

At this point, the astute reader is probably thinking that a high speed flash is worthless without an equally fast way of triggering it. You’d be right, but [td0g] already figured that part. A couple years back we covered his incredible ballistic chronometer which is being used as a sensor to fire off his new flash.

LED Panel Lamp Is A Great Way To Use Protoboard

May 13, 2019 by Lewin Day 9 Comments

It’s now possible to source chip-on-board LED modules that have huge light output in a simple, easy to use package. However they can have major power requirements, and cheaper modules are also susceptible to dead spots. [Heliox] put together a great LED lamp design the old-school way, showing there’s more than one way to get the job done.

Standard SMD LEDs are the order of the day here. The LEDs are laid out on protoboard in neat rows, making them easy to solder in place. This also makes power distribution a cinch, with the copper traces carrying the power to each row. Power is courtesy of 18650 lithium batteries installed in the back of the 3D printed housing. A GoPro-style mount is printed as part of the case, allowing the lamp to be easily mounted in a variety of ways.

It’s a quick, cheap and easy way to build a versatile LED lamp. With a diffuser installed and integrated USB charging, we could see this making an excellent portable device for on-the-go videographers or technicians. We’ve seen [Heliox]’s LED creations before, too. Video after the break.

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