Kevin Rye designed a simple LED tester:
I decide to put together a small LED Tester board. It’ll be powered by a small coin cell battery. I can pick up an LED with a pair of tweezers and just simply tap it to the solder pads. If it lights up, I know I’m holding it the right way, or not. As far as a PCB, I want it to be super simple and super cheap. I really don’t want to spend $10 bucks on something so simple. However, I don’t want it to be a one-trick pony either. Ideally, it should work for through-hole LEDs as well, as 1206s and whatever other sizes I can’t think of right now. Do SMD LEDs come in an 0805 package? I’ve never seen one, but it’s probably a good idea to place some large pads on it so that it’ll work for anything.
Kevin’s LED tester - [Link]
Andrew Rossignol has written an article detailing his YALEDD – 16×16 LED display project:
The class was instructed to choose a simple circuit such as an LED flasher or a simple sequential state machine composed of discrete logic, capture the schematic, layout the PCB and have it made by the end of the term. I decided that it would be boring to design a simple state machine. I also thought it might be pretty cool to have an electronic gizmo of my own design to show off on my desk at work.
YALEDD! 16×16 LED display - [Link]
Series of the Osram Duris S5 white LEDs brings an excellent version for an excellent price, while maintaining a long lifetime and a high CRI.
Series of the Osram Duris S5 white LEDs brings an excellent version for an excellent price, while maintaining a long lifetime and a high CRI. Some members of the family of mid-power LEDs Osram Duris were introduced to you a year ago in the article A light without an end with OSRAM Duris E3 and E5 LEDs. So far, these basic series were available:
- Duris E3 – white LEDs LED 3×1.4 mm with a max. current of 30 mA in a cost-effective plastic package. Suitable for general usage in lighting, mainly at construction of replacements of classic light sources (retrofits)
- Duris E5 – white LEDs 5.6×3 mm with a max. current of 180 mA in a cost-effective plastic package. Suitable for general usage in lighting, mainly at construction of replacements of classic light sources (retrofits)
Duris P5 – white LEDs 2.6×2.2 mm with a max current of 200mA in a resistant ceramic package. Handles high temperatures, extremely resistant to corrosion, long lifetime. Suitable for professional usage in lighting, mainly at construction of powerful light sources with a long lifetime.
The latest increase of the Duris family is the S5 series, which so to say merges the best of the E5 and P5 series. In other words Duris S5 represents a “golden middle way” between E5 and P5 and brings an excellent economical effectivity (low price), high light output and a very good lifetime. S5 is produced in a small epoxy-based package (3x3mm) with very good thermal properties. what enabled to increase power of this series.
Duris S5 also brings another valuable feature – high flexibility, because a pinout is the same as in several competition products and mainly
Notice the double voltage at the type PSLPS1, what indicates, that inside it contains 2 LEDs connected in series and at the same time it mains practically double power in comparison to type MS1. Features of particular types are best illustrated in an attached table. It´s also worth to notice the value „binning current“ and also columns „Typ. flux“ and „Typ. efficacy“, which display measured values at a given testing current. High efficacy up to 125lm/W at the type MS1 is reached at current of 65mA and serves mainly as a reference value for comparison with other LEDs from other producers, which are often tested just at such lower currents (even though in fact the type MS1 can handle up to 240 mA). In general it applies to all white LEDs, that they reach a higher efficacy at lower than maximum currents, mainly thanks to a lower chip temperature.
Into our standard stock offer we incorporated the most powerful type GW PSLPS1.EC in a warm white (3000K) and a cold white (5000K) version. Despite truly miniature dimensions, it is a considerably powerful LED with a max. power of >1W for a very affordable price. . Interesting and in praxis still more used is a possibility to use both types on a PCB (warm and cold white) and by means of a variable driving current we can change a resulting color temperature of a radiated light from warm to a cold white – according to a wish or a frame of mind of a user.
Further information will provide you the Duris S5 datasheet. It´s also a good news, that Osram promises to launch on the market a version with a min. 90 CRI.
Duris S5 – the best of the Osram Duris white LEDs family - [Link]
By Katherine Derbyshire:
Light destroys art. Some wavelengths are more damaging, some media are more vulnerable to damage, but all curators and conservators face a fundamental conflict between the demands of preservation and the desire to display the objects in their care. These conflicts come to the forefront whenever a museum must decide which objects to display, for how long, and with what illumination. The recent emergence of museum-quality LED lighting is challenging existing assumptions about the “best” lighting for art objects.
LEDs Offer Efficient, Color-Accurate Museum Gallery Lighting - [Link]
This is a 24×6 LED matrix control board based on Syst3mX schematics on Instructables. The board is connected on the LED matrix board and an external MCU or Arduino is required to produce the control signals that are feed on GP8. The circuit is able to drive a 24×6 LED matrix using an external MCU or Arduino board. The LED matrix columns are connected on JP1, JP2, JP3 and the 6 rows are connected on JP7. There is also the option to connect 2 more rows (total 8 rows) to make a 24×8 LED matrix.
24×6 LED Matrix Control Circuit - [Link]
New, more efficient LED series from company Kingbright were recently introduced to you in our article Small but powerful LED series KP- 2012, where we presented you new stock types – red series SR-J4. Meanwhile we also enhanced our stock offer with green LED series (525nm) LED – ZGK as well as with yellow LED series – SYK. All these series have one feature in common – high efficiency, whch is praxis reflected in two aspects:
- significantly higher luminous flux than standard types (at the same current) or
- significantly lower current necessary to reach the same brightnessFor illustration we attach series of snapshots from the same device with two different green LEDs (various expositions at a common indoor lighting). In the left device, there´s a standard LED, in the right one the KP-3216ZGCK is used (compare only a green LED, red LEDs are the same). We believe, that these pictures say it all – the difference is really very big.
It´s necessary to mention, that because of a different technology of a chip, the operation (forward) voltage of the ZGK series is higher than at standard types, i.e. approx. 3.3V, 2V at a yellow series and and 2.2V at red series. As a value of brightness (cd) is dependent on a radiation angle, this value is at SMT types without optics always lower than for example at 5mm or 3mm THT LED. However, that doesn´t mean, that a given LED provides less amount of light – overall luminous flux of these types with the same chip is the same. The only difference is that LEDs with optics focus light into a narrower radiation angle. Detailed information will provide you the Kingbright SR-J4, ZGK and SYK datasheets. Type „C“ at marking of many LEDS – for example ZGCK, SYCK means a transparent package (Clear).
Save 90% of LED power consumption with new types from company Kingbright - [Link]
By Shawn Rhen:
Despite the initial investment, solid state lighting (SSL) has proven to be a viable alternative over conventional technologies due to the combined savings in energy consumption and maintenance costs, as well as design flexibility. Furthermore, increased energy savings can be realized with active intelligence such as occupancy and ambient light sensors, as well as external dimming controls to eliminate excessive lighting. Since there are a wide variety of constant current LED drivers requiring a 0-10 volt DC input for dimming control available, the focus of this discussion will be utilizing these drivers with a wireless interface.
Wireless Control of Linearly Dimmed LED Drivers - [Link]
What’s inside a modern 18W LED Fluoro T8 replacement tube from German company Mueller Licht?
EEVblog #533 – LED Fluoro Tube Teardown - [Link]
by Steven Keeping:
LEDs have many advantages over traditional lighting including efficacy, longevity, and robustness, but price is not one of them.
The reason why LEDs are expensive is partly because the manufacturing process used to fabricate the wafers from which the individual chips are cut is difficult and employs exotic materials such as gallium nitride (GaN) deposited on sapphire or silicon-carbide (SiC) substrates.
But recently, some manufacturers have proposed using silicon, the material routinely used to fabricate billions of integrated circuits (ICs) every year, as an LED substrate. Apart from potentially reducing the cost of LEDs, the use of mature complementary metal oxide semiconductor (CMOS) IC technology would allow fabrication in conventional wafer fabs that have spare capacity.
Will Silicon Substrates Push LED Lighting Into the Mainstream? - [Link]
Carolyn Mathas writes:
There’s a new high-density class of CXA arrays from Cree that doubles the lumen density for next-gen LED spotlights. The CXA 1520 is the first HD Array announced under the breakthrough technology. It enables lighting manufacturers to create products that deliver the same intensity and light quality as 39W ceramic metal halide (CMH) at up to 50% lower power.
Cree rolls LEDs with double lumen density and 50% less power - [Link]