The new XLamp XP-E2 LEDs from Cree are claimed to deliver more lumens per watt and lumens per dollar to lower system costs for existing XP-E and XP-G designs. The new LEDs can increase the light output of existing XP-E designs at the same cost and power or reduce the system cost with fewer LEDs, enabling lighting manufacturers to deliver better lighting systems with minimal redesign.
The LEDs have the standard XP footprint (3.45 x 3.45 mm) and are optically compatible with all XP LED versions, including the popular XP-E and XP-G. The LEDs generate cool white light (6000 K) at up to 128 lm/W at 350 mA and 85 °C or 143 lm/W at 350 mA and 25 °C and are suitable for a broad spectrum of high-lumen applications for indoor and outdoor lighting, portable lighting and lamp retrofits and. [via]
New LEDs Double Lumens per Dollar - [Link]
The concept for this small birthday present was to create a small heart shape with red LEDs and then to draw a heart shape underneath it on the PCB as a backdrop. Then a small processor was added to control the heart shape of LEDs for both fade and pattern control. The method of control that we use (PWM) allows us to save precious battery life, control the exact brightness of each specific LED and create this tiny but awesome project.
LED Heart PWM Fading – [Link]
We create a lamp controlled by SMS using a GSM shield, a RGB shield and a Arduino UNO. Due to the simplicity of these boards, simply plug one over the other and connect a strip led to have a lighting effect. Then sending normal text messages from any phone, you can turn on and choose the color to set.
IKEA SMS lamp with GSM shield - [Link]
The LM3463 by Texas Instruments is a six-channel LED driver with dynamic headroom control for high-power applications that accurately drives up to six strings of LEDs. The biggest cost reductions in LEDs today come from improvements in efficacy (fewer LEDs needed for the same light output), and the LM3463 is no exception.
It is the industry’s first wide-input voltage LED driver featuring multiple dimming control modes—PWM input signals, analog-to-PWM input control, or 4-byte data control—to maximize system efficiency and reduces complexity in LED area lighting. The driver targets such bright-light applications as street, high-bay and ceiling lighting. When designers require PWM, the LM3463 is particularly useful as it accepts a simple serial data stream and the LED driver creates the PWM signals internally. It can, therefore, be used with a fairly inexpensive MCU and it easily adjusts brightness. [via]
High-power LED driver features multiple dimming control modes - [Link]
Shawn Rhen writes:
The advancements in high powered LEDs have brought them to the attention of the lighting industry, positioning them as replacements for the current incandescent and fluorescent technologies. Although widespread adoption has not yet come to fruition, opportunities exist in which these present lighting technologies are unable to compete, a fact that has been realized by lighting architects for years.
Most prevalent is the ability to produce multi-colored illumination for accent, automotive, and signage applications. It is this aspect of high powered RGB LEDs on which we will focus.
In order to produce consistent and repeatable colors, the first design criteria that must be met is that of a constant drive current for each of the RGB die. As shown in Figure 1, this is accomplished utilizing 1 amp maximum constant current drivers that are adjustable with trimmer potentiometers and powered from a 5 volt DC supply.
High Power RGB LED Color Mixing - [Link]
Current controlled boost LED driver and black soldermasks @ Limpkin’s blog – [via]
[Here's] all you need to know to design your own LED driver based on the MAX16834 and also give you the design spreadsheets that are quite long to get.
Current controlled boost LED driver and black soldermasks - [Link]
Ishan Karve writes:
I have made a 16×8 led word clock, a rectangular one. Break from square or almost square ones. This one is a complete modular design and can be scaled up or down in size / complexity according to ones need. The whole design and requisite files are in open domain and the project has also some good 3d pcb renders. The main clock controller is arduino-like and is again scalable.
The LED panel is composed of 8 individual panels of 4×4 LEDs. Each group of 4 such panels will be controlled by a MAX7219. Here are the schematics and board layouts of the 4×4 LED board and LED driver … They are on the way to a fab house….In the meantime I shall do 3D render of my project. Schematics & PCB designed using Eagle CAD 6.2.0 Lite Running on Linux Box.
16×8 LED Word Clock - [Link]
O’K, after having some fun with stereo version of the VU meter I described in my previous blog-post, now it’s time to do a serious stuff. Studio grade VU meter !!! 24 steps, equally spaced every 3 dB, covering Extra wide Dynamic Range from -63 up to +6 dB. Single (mono) channel this time, no messing around, absolute precision at the stake. Plus, it keeps absolutely Top-Flat linear frequency response from 40 Hz up to 20 kHz(*).
Audio VU meter with extra wide Dynamic Range 69 dB - [Link]
Physicists at the University of Utah (USA) have invented a new ‘spintronic’ organic light-emitting diode (OLED) with the potential to be brighter, cheaper and more environmentally friendly than existing LEDs. They made a prototype of what is called a spin-polarized organic LED, or spin OLED, that emits orange light. In time the new technology could be extended to emit red and blue light, and possibly even white light. It may take a while for the new LEDs to go commercial, because they only operate at cold temperatures (-33 °C), so more work is needed to develop practical devices.
The new OLED is based on spintronic devices, which utilise the spins of electrons in a semiconductor material to store or gate data. The researchers discovered that with key advances in the organic semiconductor material, spin valve devices could also be made to emit light. The first advance is to use deuterium (‘heavy hydrogen’) instead of normal hydrogen in the organic layer, which increases efficiency. The second advance is to deposit an extremely thin layer of lithium fluoride on the cobalt electrode, which allows electrons to be injected on one side of the spin valve while holes are injected on the other side. This makes the spin valve bipolar, unlike older spin valves which only allow hole injection. [via]
New OLED Spins Brighter - [Link]
This article shows you how to create a VHDL module in an FPGA or CPLD that can output a dynamic PWM signal to fade LEDs in and out, creating a cool visual effect. The hardware schematic, source code, parts list and theory are all included in the article.
CPLD LED Fading - [Link]