Tearing Down A Failed LED Bulb

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[Todd Harrison] was thinking of replacing some incandescent light bulbs in his house with LED models, so and his wife picked up a single candelabra bulb to test before they spent the cash to swap them all out. The bulb died in about a week’s time, so [Todd] got out his trusty electronic disassembly device (his hammer), sharing his post-mortem examination with us.

After taking a cursory look at it, [Todd] found that the circuit powering the bulb was not overly complicated. A small bridge rectifier along with a few caps and resistors are all that was used to power the device, making it’s failure a bit puzzling. When [Todd] wired it up to his power supply, the bulb lit up, much to his surprise. His best guess as to why it died is that the shrink wrap around the PCB managed to cause a short, though he also noticed that one of the bridge rectifier’s legs was not soldered down.

He started tooling with the light to find out more about it, but he managed to blow out a handful of LEDs in the process. All in all the LED lighting swap was a disappointment, but at least he had some fun along the way!

Continue reading if you’re interested in seeing [Todd’s] diagnosis in its entirety.

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Color Changing Coaster Has A Built-in Drink Detector

[Robert] put together his own illuminated coasters that know when they hold a drink. They look fantastic, thanks to professionally produced PCBs and a layered, laser-cut acrylic case. They’re much like the pagers given to restaurant-goes who are waiting for tables, but this version is much fancier (and doesn’t include the vibrating/paging feature).

The RGB-LED board is a previous project which was developed using eight surface mount RGB LED modules around a circular board. It uses an ATmega168 paired with an MBI5168 constant-current LED sink driver. The coaster enclosure gave him room for a few more items, like the pair of AA batteries which work in conjunction with a boost converter to power the device. It also houses an IR reflectance sensor which is used to detect the presence of a drink on the coaster. This is important since an on-occupied coaster looks like it would be blindingly bright if there wasn’t a glass to diffuse the intensity of the LEDs.

He mentions that incandescent light bulbs mess with the IR reflectance sensor. But there must be some way to account for ambient conditions with the code, right?

USB Controlled SPÖKA Night Light

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[wejp] picked up an IKEA SPÖKA night light, but he wasn’t entirely impressed with its functionality. Pressing the top of the ghost’s head causes it to cycle through a few colors, and pressing it a second time locks it into displaying the current color until its tapped again. Inspired by this SPÖKA hack which used a different version of the night light, he tore his down to see what he could do with it.

Upon stripping off the outer cover, he found that the internals were considerably different than those found in its glowing brethren, though they were perfect for what [wejp] had in mind. He removed the rechargeable battery pack as well as the controller board, which sits on a PCB separate from the LEDs. He replaced the stock micro with an ATtiny25, which he uses to give himself a bit more control over the light display.

He couldn’t quite cram all the functionality he desired into the ATtiny, but he planned on powering the light using his computer anyhow, so he installed a small USB port in the back. When connected to his PC, the SPÖKA can be controlled more precisely than when it operates alone.

Unfortunately there’s no video available of the SPÖKA light in action, but there are plenty of images available on his site.

Becoming The YouTube Loading Animation

Whether you’re used to dropped wifi connections, or your housemates are using up all the bandwidth for streaming, we’ve all see the spinning octet of disks that is the YouTube loading animation. [technocrat] thought it would be a great idea to actually become YouTube and set out on designing a physical manifestation of the loading animation.

[technocrat] used eight ping-pong balls as the main structure of the build. After drilling each ping-pong ball and gluing white LEDs in, the only thing left was to connect everything up to an Arduino. The code loops through each LED and provides the ‘light trail’ animation YouTube has burned into our memory.

To complete the build, [technocrat] attached his physical loading animation to a black t-shirt emblazoned with the YouTube logo to make everything more understandable. While it may not be as colorful as the beachball of death or as conceptual as the Windows ‘spinning hourglass’, we’re really liking this build. Check out the video after the break.

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LED Tutorial Demystifies Several Control Techniques

Controlling LEDs is really quite simple. As you know, they need to be current limited which is as easy as applying Ohm’s law to your given set of values. To make things even more even there’s a slew of constant current LED driver chips out there that can be had for a song. But do you have any idea how those constant current circuits work? If not, then [Giorgos Lazaridis’] guide on LED driving and controlling methods will bring you up to speed in no time.

He starts out with the most basic concept, how to light an LED using proper current limiting resistors. But from there he moves on to the juicy bits. He builds a transistor-based constant current driver, then adds voltage regulation for the circuit as seen in the schematic on the left. He moves on to the more robust and efficient method on the right which pairs a MOSFET with that transistor circuit. This is the technique found on each pin of many of those constant current drivers and functions well regardless of the voltage input level.

He’s been producing videos to go along with these articles. After the break you can watch the episode that accompanies the schematic on the left. Continue reading “LED Tutorial Demystifies Several Control Techniques”

Adding A Lot Of Twinkle To This Rebar Sculpture

Blinky lights have a way of attracting attention and that’s exactly what the members of the Maui Makers hackerspace were shooting for. The sculpture above is the logo for the Source festival, a Burning Man inspired music gathering in the Aloha state. For this year’s festival they went crazy, installing twelve meters of RGB LED strip controlled by seven Arduino boards.

The goal was to make the twelve-foot tall sculpture into a lighted interactive showpiece. In addition to the LEDs it includes a microphone, capacitance sensors, Bluetooth connectivity, and a piezo speaker. There’s one Arduino to rule them all, with another Teensy controller to drive an LCD display in the control box, and five Teensy boards to address the LED strips. They grabbed [Bill Porter’s] Easy Transfer library to facilitate communication between the microcontrollers (his libraries are becoming popular, we just saw his mp3 shield library used in another project on Tuesday).

The code which drives the LED animations is based on some Adafruit examples. We really enjoy the waving flag effect seen in the clip after the break.

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Simple Hardware And Python Drive This Splunk LED Meter

Want to monitor the company system without continually loading up the Splunk dashboard? It turns out that they’ve got their own Python package which makes pulling down data a snap. All [Rick] needed to do was hook up an LED meter as an external display.

It used to be that this would take a lot of wire and bit of soldering (or some special Christmas lights), but the advent of affordable LED strips has really taken the guess-work out of it. He’s using an RGB version acquired from Adafruit Industries. These strips are driven using SPI and multiple-colors mean you can display multi-dimensional data using one column. He chose to use a Teensy microcontroller, grabbing some plastic packaging for welding rods as the enclosure. These strips are extremely bright and to help soften the impact he added wax paper to the inside of the enclosure to act as a diffuser.

Looking for more projects that use strips like this one? They make fantastic addressable accent lighting for your home.