by w2aew @ youtube.com
The Humanalight is a simple single-cell flashlight kit that will produce usable light, even from a “dead” AA battery. Circuits like these are often called a Joule Thief. This term has been applied to just about any circuit that allows you to boost the voltage from nearly depleted batteries for some other low-power application – such as lighting an LED. Strictly speaking, a Joule Thief circuit is an Armstrong style blocking oscillator that uses a bifilar wound transformer and relies on the saturation characteristics of the core to produce oscillation. This flashlight uses a simple two-transistor relation oscillator. A description of the circuit is given, and its operation is examined by viewing the waveforms on an oscilloscope. The proceeds from the sale of this kit benefit the “Ears To Our World” charity which provides self-powered radios and other technology to rural, impoverished and remote regions of the world.
Circuit Walkthrough: A single cell LED light - [Link]
MUNICH — At Electronica last week, the LED manufacturer Everlight introduced what it claims to be the world’s first colour-temperature tunable LEDs in a simple chip on board (COB) package.
After brightness dimming, tunable color temperature is a feature that allows end users to tune the warmth of the light they receive. Typically, this feature is implemented through the use of multiple LEDs binned from cool white to warm white, behind a diffuser.
With its CHI3030 27V/29W series, Everlight claims to have a very compact solution, with LEDs packaged behind concentric layers of phosphors offering different color temperatures of white. Depending on how much warm white or cool white you choose to light up, you can get a precise color-temperature mix.
New LEDs offer tunable color temperature - [Link]
by dany @ elecfreaks.com:
Smart RGB LED Strip is based on the development of our BLEduino, using the Bluetooth 4.0, and the sample code written by EF men, by mobile phone APP, to control the switch of RGB LED strip, and the RGB LED color changing. The main principle is that using BLEduino mega328P chip three PWM pins respectively to control the RGB LED strip of R G B three colors. When the phone APP and BLEduino bluetooth pairing connection succeed, phone APP can control mega328P chip three PWM pins output value, then control the the color of the RGB LED strip
Smart RGB Strip with BLEduino DIY Guide - [Link]
Francesco Truzzi published a new build, a 3-channel (RGB) LED driver:
I built another board, which is a 3-channel (RGB) LED driver based on an inexpensive chipset called PT4115 (you can find them on eBay or Aliexpress).
The circuit is very simple and looks like Sparkfun’s PicoBuck. However, I used beefier components and a different chip. You may say it’s pretty much the same thing, but I made it to learn some more about PCB design.
Datasheet here. LED current is set through a sense resistor. The output current I is equal to 0.1/Rs. I wanted ~300mA for each channel so I chose a 0.33 ohm resistor. If you want 350mA, choose a 0.27ohm resistor.
Each channel can be controlled via PWM (you can solder male/female headers on the board), for example with an Arduino.
Building a 3-channel, high power RGB LED driver - [Link]
by Digi-Key Corporation:
The Cree LMH2 LED Module provides unparalleled efficacy and light quality in a fully integrated module. Utilizing Cree’s True White Technology, the LMH2 provides beautiful 90 plus CRI lights in 4000 Kelvin, 3500 Kelvin, 3000 Kelvin, and 2700 Kelvin color temperatures. In addition, the LMH2 delivers 97 LPW efficacy across all CCT and lumen options. There are two lens options. The flat lens provides an 82 Degree Beam Angle while the Dome lens provides a 100 Degree Beam Angle. In addition, there is a Unique Driver Compatibility Program that provides a list of tested and recommended drivers for the LMH2. There is also a 5-year warranty on the module, even for those utilizing a third party driver. Finally, the aluminum housing provides tremendous thermal design flexibility.
Cree LMH2 LED Module Versus Traditional CFL Options - [Link]
RGB LED disco light is a simple project designed around PIC16F72 microcontroller.
This firmware is a RGB driver, as name suggests it is used to derive or light red, green and blue LEDs in particular fashion. Its main feature is the pattern shown on LEDs. It is quite difficult to describe pattern in words but we want to specify that first it will derive red then green then blue three times and then a particular pattern is shown on LEDs and again the three LEDs light.
RGB LED Disco Lights - [Link]
Wireless. Easier. Safer. Longer Lasting Christmas lights. by Chris Higgins & Hardeep Johar:
The first ever wirelessly powered Christmas lights
Smartphone controlled energy efficient LED lights
Outshines any of the average Christmas lights by 20 years
AURA: The first ever, wirelessly powered Christmas lights - [Link]
Control of up to 680 pixels on any of the popular LED strips from any device with a USB port! One controller to rule them all!
Working with addressable LED strips, we’ve found that the extra components required to communicate with and power them complicate designs and limit the options for how they can be used. Each chipset requires its own special protocol and supporting hardware components. This is where the AllPixel comes in. Think of it as a video card for your LED strips.
AllPixel – USB Interface For All Your LED Needs - [Link]
by R O Ocaya @ edn.com:
This Design Idea shows a way to drive low-power electronic circuits using a single 1.5V cell. The design is based on a free-running oscillator that drives a flyback transformer to generate a controllable higher voltage. It can be used to power analog circuitry, microcontrollers, and any other light loads.
Flyback switcher works down to 1.1V, flashes HBLEDs - [Link]