by Steven Keeping @ digikey.com:
The dominant technology for today’s high-brightness LEDs is gallium nitride (GaN) on sapphire or silicon carbide (SiC) substrates. These materials are popular because the resultant LEDs are bright, efficient, and last a long time. However, the chips are tough to manufacture and package into useable devices, multiplying the cost of end products that use them as light engines. Although prices have plummeted in recent years, LED lighting is still considerably more expensive to purchase than traditional alternatives. This initial expense is cited as a major factor slowing the acceptance of solid-state lighting (SSL).
A pioneering group of manufacturers has worked hard to reduce the cost of high-power LEDs by replacing the sapphire or SiC substrate with silicon (Si), the material routinely used to manufacture most electronic chips (“ICs”). The key benefit is a very-low-cost supply of wafers and the opportunity to use depreciated 8-inch wafer fabs for LED manufacture. Combined, those concepts enable a dramatic reduction in LED prices, overcoming consumer objections.
Improved Silicon-Substrate LEDs Address High Solid-State Lighting Costs - [Link]
by Dooievriend @ tweakblog.tweakblogs.net:
More than a year ago, a friend of mine asked me to write the software for his 3D Spectrum Analyser (3DSA): a device that takes as input an audio signal, and outputs its visualisation on a 3D matrix of leds. If the above description doesn’t quite ring a bell, simply watch the end result in action.
First things first though, the microprocessor to be programmed was an 80MHz Olimex PIC32, soldered to the PIC32-PINGUINO-OTG development board. (For those who ever tinkered with Arduino boards: it’s the same, only with a faster chip and fewer builtin libraries ) The Algorithm had to sample the input signal at regular time intervals, convert this signal to the frequency domain, and visualize the detected frequencies on a 16x16x5 LED matrix.
3D Spectrum Analyser - [Link]
Fairchild announced the FL7734 Phase-Cut Dimmable Single- Stage LED Driver, a highly integrated LED controller solution for low-cost, and highly reliable LED lighting solutions from 5 W to 30 W. The FL7734 enables designers to quickly achieve great light quality designs with high dimmer compatibility while integrating full power factor correction (PFC) circuitry to meet power factor (PF) and total harmonic distortion (THD) requirements.
The FL7734 solution uses Fairchild’s unique active dimmer driving technology to eliminate visible flicker or shimmer symptoms and deliver over 90% dimmer compatibility with a variety of leading edge, trailing edge and digital dimmers from a wide range of manufacturers. The solution fully meets NEMA SSL 7A-2013 & ENERGY STAR® standards and provides a programmable dimming curve and input current management flexibility.
Fairchild Simplifies Dimmable LED Lighting Design - [Link]
LT series LED drivers with 10-100W power represent a complete solution with wide possibilities of control. Exceptionally narrow and slim design, remained even at high-power versions, provides a high flexibility of use.
Power supplies for LED lighting (so called drivers) are available from many producers, in a various qualitative level. Why to decide just for the LT series from German company Friwo? Here are few reasons:
- precise design, safe operation and a long lifetime
- voltage and current regulation in one device
- high efficiency and a possibility of dimming in a range of 0-100% directly via a CTRL pin
- modules are available in 10-100W power, with a possibility of customization by laser directly at production
- also available a module for dimming – so called DIMMbox, further expanding possibilities of control (switch, 1-10V, DALI) and with a possibility of synchronization with up to 1000 slave units
- very small cross section of modules (21x30mm, resp. 24x30mm at LT100) – applicable even in very tiny conditions
Wide control possibilities of LT series modules are perhaps the most interesting. Modules contain a galvanically isolated CTRL input, by which it is possible to switch on/ off the module without disconnecting from 230V mains. CTRL pin also serves for regulation of an output current. For this purpose, only one resistor (or a potentiometer) is necessary – connected between SEC+ and CTRL pins, with a value counted by a simple formula in the datasheet. The output current can also be controlled by an external voltage in the range of 0-1,8V connected to SEC- and CTRL, as well as by means of a PWM TTL (0/5V).
Further possibilities of control are provided by a standalone additional module DIMMbox. DIMMbox operates as an (almost) lossless PWM regulator with a MOSFET switched at f=600Hz. DIMM-BOX connected to any series LT driver enables to regulate an output current in a range of 10-100% or 0% (OFF) via a usual switch („switch-dimm“ mode), via a linear voltage 1-10V and also a DALI interface. DIMMbox tests after switching on, which of three methods of control is used and consequently accepts only signals from a given input – until switching off the module. DIMMboxes can be connected through SYNC inputs, ensuring the same level of dimming for all modules. Enclosed pictures will provide you the best idea about possibilities of connection.
Every power class is available in several versions, with various output voltages and currents . Detailed information will provide you the LT series overview, DIMMbox datasheet, as well as datasheets of particular models, for example LT20 or LT100.
Friwo LED drivers will light up your LEDs as much as you just want - [Link]
by CsabaP @ instructables.com:
This Instructable shows you how to build a clap activated LED strip. The whole project is based on the Adafruit’s Secret Knock Activated Drawer Lock, where the user can record a secret knock pattern which will open the lock inside the drawer. I thought that I could use this to siwtch an LED strip on and off with a handclap pattern. So let’s begin!
Clap activated LED strip - [Link]
Impress your friend with the ultimate geek’s Birthday Cake! A hand-made open source electronic cake with candles you can blow out!
- Features 9 LED candles that you can blow on, to make them flicker and go out, like you do with a real birthday cake! Each candle blinks with random period and phase that depends on the intensity of the air flow
- Piezo sensor and a special air trap to detect air flow with astounding sensitivity using resonance effect
- Atmel ATTiny44 microcontroller on board with 4 kilobytes of flash memory and 256 bytes RAM
- Open source hardware and firmware. Can be re-programmed with an ICSP programmer or Arduino board via Arduino IDE
- Size 42 x 42 x 18 mm, weight 26g
- Powered by a single AAAA/LR61 battery (included)
- 3.3V step-up converter on board
- Ultra low shutdown current (less than 1 uA in deep shutdown)
- Hand-soldered using lead-free solder
BitCake – Electronic Birthday Cake - [Link]
by Rui Santos @ randomnerdtutorials.com:
If you want to learn more about the ESP8266 module, first read my Getting Started Guide for the ESP8266 WiFi Module. In this project you’ll create a standalone web server with an ESP8266 that can toggle two LEDs.
Why flashing your ESP8266 module with NodeMCU?
NodeMCU is a firmware that allows you to program the ESP8266 modules with LUA script. And you’ll find it very similar to the way you program your Arduino. With just a few lines of code you can establish a WiFi connection, control the ESP8266 GPIOs, turning your ESP8266 into a web server and a lot more.
ESP8266 Web Server Tutorial - [Link]
SosElectronics offers you simply applicable solution of a power LED on a thermal clad in a special offer!
- power white SMD LED Luxeon Rebel
- luminous flux min. 100 lm / 350 mA
- specified to continuous 700 mA / 3,2 V
- made on a ceramic base with electrically insulated thermal pad
- guaranteed lumen maintanance 70% of original value at 50 000 hrs / 700mA / Tj 135°C
- low moisture sensitivity – JEDEC Level 1
- dimensions: 4,61 x 3,17 x 2,10 mm
- thermal clad for Lumileds Luxeon Rebel
- optimal heat transfer from LED to heatsink
- longer LED lifetime and luminosity thanks to a lower operating temperature
- star board
- easy application
Readily usable LED for exceptional price - [Link]
by Donald Schelle @ ti.com:
Achieving optimal performance of an LED luminaire or LED backlight design requires numerous trade-offs. Understanding an LED’s power transfer characteristics empowers intelligent choices regarding cost, power consumption, and weight. While most LED datasheets publish pertinent data that can be used to make these decisions, data may not be formatted in a way that is readily applicable to the chosen application. Optimal performance requires finding pertinent information from manufacturer’s LED datasheets and utilizing methods to capture, reformat and analyze the data.
Optimal operating point of an LED - [Link]
by Henry Tonoyan @ htonoyan.blogspot.gr:
Last week I had the idea to create a last-minute valentine’s day gift for my girlfriend. I had a bunch of WS2812 LEDs from my previous endeavors and decided to make a big LED heart. These are a great choice because of the very minimal amount of components necessary: no I/O expanders, driving transistors or ICs necessary. Plus you just need one I/O line from your microcontroller to drive them.
Since they run off 5V, I planned to create a board that is powered from a wall-wart power supply. That way the board doesn’t even need a voltage regulator on it. I chose to use an ATMega48 because I have several from previous projects.
A Valentine’s Day Surprise - [Link]