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9 Jan 2012

electrobob.com writes:

I have recently stumbled upon some LED strip at my local electronics shop and decided to give them a try. I bought some which I used to replace the spot lights in the kitchen. It is cold white, which is surprisingly good, especially for night time illumination (think moonlight like hue). It works at 12V and consumes about 0.25A per meter.

After installing the strip, some automation proved to be necessary, and so the following circuits were built. The goal in mind was to keep things as simple as possible and use only parts I had at hand, which is why the solution might not be the best.

The hallway spotlights got new white LEDs as well and a light sensor. Tiny PIR sensors will turn on the lights in the kitchen and bathroom when someone comes in range. The sensors are rather popular modules using a BISS0001 IC; they provide a 3.3V level for an adjustable time when motion is detected.

Overall the results are great. The hallway is lit at night, the there is a small automatic light for the bathroom and the automatic kitchen light is bright enough even for day time illumination of the sink and counter. The slow turn off provides both a visually pleasing effect and a warning in case someone stood still long enough to make the light go off. I am still looking for a simple solution to produce the same effect on turn on, but without the delay.

Fun with LEDs - [Link]

3 Dec 2011

Kristin Lewotsky writes:

LEDs have a well-deserved reputation for high-efficiency operation, not to mention high reliability. Properly specified and implemented, LEDs should and do satisfy virtually every lighting application. Still, there are times when actual device lifetimes fall short of the specified ideal. LEDs are wide-bandgap semiconductor devices. As a result, they have far more complex and varied failure modes than the incumbent technologies. Unlike an incandescent lamp, where failure is fairly simple (the bulb produces light until the filament breaks), with an LED, the failure modes range from mechanical and electrical to material.

Understanding and Preventing LED Failure - [Link]

29 Nov 2011

Paul Dietz, William Yerazunis, Darren Leigh write:

A novel microprocessor interface circuit is described which can alternately emit and detect light using only an LED, two digital I/O pins and a single current limiting resistor. This technique is first applied to create a smart illumination system that uses a single LED as both light source and sensor. We then present several devices that use an LED as a generic wireless serial data port. An important implication of this work is that every LED connected to a microprocessor can be thought of as a wireless two-way communication port. We present this technology as a solution to the “last centimeter problem”, because it permits disparate devices to communicate with each other simply and cheaply with minimal design modification.

LEDComm: Bidirectional Communications using LEDs - [Link]

28 Nov 2011

Mini RGB LED video wall using a Netduino and an Adafruit LED strips… [via]

16×10 RGB LED display built with an Adafruit LPD8806 LED strip and a Netduino mini as the controller. The display is capable of showing over 2 million colors. What’s not to like about RGB LEDs? With their bright, mesmerizing glow, often capable of displaying millions of colors, they’re a great to way to catch the attention of the viewer. Now, what if you had a 5 meter long RGB LED strip, loaded with 160 RGB LEDs to play with? Oh, the possibilities… It so happens that Adafruit, in their infinite wisdom, carries a very nice RGB LED strip, powered by a LPD8806 driver and encased in a waterproof sleeve. What about turning it into a mini video wall for instance? Think ‘Times Square’, just smaller

Mini RGB LED video wall using a Netduino - [Link]

24 Nov 2011

ColorNode » DigitalMisery.com – [via]

ColorNode is a wireless Arduino-compatible microcontroller board designed to replace the stock controller board on GE Color Effects light strings.

ColorNode was inspired by the original controller protocol reverse-engineering effort featured here: Hacking Christmas Lights. That work enabled simple control of each individual bulb of these light strings using just one pin on a microcontroller. The stock controller works nice and the patterns are good, however being able to have full control of the color and brightness of each bulb unlocks the potential for awesome holiday light displays. Hacking these lights is also relatively inexpensive, compared to using other addressable strings or light sequencers on the market.

ColorNode – OSHW LED string controllers - [Link]


18 Nov 2011

TRIAC Dimmable LED Driver

LT3799 isolated LED controller with active power factor correction (PFC) is specifically designed for driving LEDs over a wide input range of 24V to 480V+. It is ideal for LED applications requiring 4W to over 100W of LED power and is compatible with standard TRIAC in-wall dimmers. The LT3799’s unique current sensing scheme delivers a well regulated current to the secondary side with no opto-coupler, enabling it to provide ±5% LED current accuracy. It also offers low harmonic distortion while delivering efficiencies as high as 90%. Open and short LED protection ensures long term reliability and a simple, compact solution footprint addresses a wide range of applications.

TRIAC Dimmable LED Driver - [Link]

17 Nov 2011

Now, you can experience the energy-saving benefits of LEDs combined with Sharp’s true-to-life color rendering in applications previously limited to a 50W incandescent, halogen, or compact fluorescent equivalent. Meet Sharp’s new 10W Mini Zenigata.

This new module utilizes a 6 (series) x 10 (parallel) LED matrix that delivers a luminous flux between 610 and 690 lm. Sharp’s entire Mini Zenigata product line delivers an impressive CRI value of 87, exceeding ENERGY STAR requirements (minimum of 80 CRI).

The new 10W Mini Zenigata joins Sharp’s existing 3.6W, 4W, 6.7W and 7W Mini Zenigata products to offer chromaticity performance tighter than that defined by existing ANSI CCT standards (under 3 Macadam ellipse). Be sure to review our specification table below on this page to view updated features to many of our 3.6W, 4W, 6.7W, 7W and 10W products.

The Mini Zenigata product family gives a new meaning to “compact,” with approximately half (56%) the surface area of previous models and a significant reduction in the emissive area when compared to our Zenigata offering. Mini Zenigata modules provide an operating life exceeding 50,000 hours at a service temperatures of 80°C.

Mini Zenigata Leds - [Link]

11 Nov 2011

adafruit.com writes:

16×24 LED Matrix – Easy to use, chainable displays. These LED panels take care of all the work of making a big matrix display. Each panel has six 8×8 red matrix modules, for a 16×24 matrix. The panel has a HT1632C chip on the back with does all the multiplexing work for you and has a 3-pin SPI-like serial interface to talk to it and set LEDs on or off. There’s a few extras as well, such as being able to change the brightness of the entire display, or blink the entire display at 1 Hz.

16×24 LED Matrix – Easy to use, chainable displays - [Link]


5 Nov 2011

Thanks to an increasing interest about LEDs OSRAM from our offer, we can now offer you selected types for lower prices.

As we all see, LED light sources experience a global „boom“. Their usage thereby also their sale grows. Thanks to it, we are taking on stock still bigger ammount and we managed to gain notably lower prices. And as your those, for which we do our work, we automatically reflected these lower purchase prices to your favour – into sale prices. Namely, we decreased prices at selected types of Advanced Power Topled Plus, Golden Dragon oval Plus and Golden DRAGON Plus series, listed in the product list under this article.

LEDs OSRAM have a very quality and thin luminophor layer. Also thanks to this, LEDs OSRAM provide a very colour-uniform luminous flux even in corner angles of the radiation pattern – unlike various no-name power LEDs, which often provide significantly more yellowish light at the corners of the radiation pattern.

Detailed description of all types you can find on the OSRAM website.

Save costs at selected OSRAM LED types! - [Link]

5 Nov 2011

To connect wire leads to LED panels is easy, elegant and professional with poke-in connectors from TE Connectivity.

How to connect wire leads to PCB so that they had a reliable contact and didn´t require hand soldering? We probably will get an idea of more possibilities by means of various terminals. But what a terminal or connector to use, so that it looked professionally, didn´t act disturbing and had a low profile which doesn´t shade LEDs?

Poke in connectors from TE Connectivity are designed specially for lighting purposes. They are available in an SMT as well as a THT version. High temperature material enables reflow soldering together with other SMT components. Connection of wires themselves then requires only a simple insertion of a wire with a 7mm stripped part. For a simple strip length check, the connector has the strip length gage.

Connectors are available with a standard as well as low insertion force. It is possible to use 18, 20 and 22 AWG wires, 18-20 AWG stranded pre-bond wires, as well as 18 AWG stranded wires. They have a low profile and rounded corners to minimize shadowing. Relatively robust construction and redundant pads increase mechanical stability and prevent peeling of connector from PCB. If using more connectors side by side, they are stackable with pads on 4mm centers. Flat top surface allows for problemless vacuum pickup. Connectors are available in 1 and 2 positions, in SMT as well as THT version. White (cream) or black colour enable to differ polarity. For a maximum corrosion protection in outdoor and humidity environment also gel-filled types are available.

Connect the LED panels without soldering – with TE connectors - [Link]





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