Dilshan Jayakody wrote a post on his blog about his 3W constant current LED driver:
This is quick post about 3W constant current LED driver which I was design to combine with some homemade furniture piece. The main components of this system is LM311 voltage comparator and IRF9640 P-Channel MOSFET. This module is design to drive maximum of two 3W high power LEDs and it requires 8V – 10V DC (500mA) power source. In this given configuration this module may not need any heat-sink (for IRF9640) and consume maximum of 500mA of power.
DIY 3W constant current LED driver - [Link]
Dave Kruschke writes:
Yep, no transformer and no hard to get IC. But, … two transistors and other parts are required. I actually found this circuit by accident while roaming Colin Mitchell’s Talking Electronics website (talkingelectronics.com). This website is very rich with examples and explanations of a huge variety of circuits. In fact, this website is so abundant in circuits that later on, I couldn’t find the circuit revealed here. Anyhow, I believe that the TE circuit can be considered “robust” as it works even if different parts are used.
“Joule Thief” – no IC and no Transformer - [Link]
Raj @ embedded-lab.com build a mini LED Christmas tree for his son. He writes:
My two and a half year old son loves toys with flashing lights. For this Christmas I thought of making a mini LED Christmas tree for him. This project uses 22 multi-color LEDs which are driven by a PIC12F683 microcontroller using the Charlieplexing technique. The details of the build procedure is described in the following sections.
Making a mini LED Christmas tree - [Link]
By Gina Roos,
Widespread adoption of cameras in smartphones and other mobile devices, together with consumer expectations for higher quality, sharper images are driving the need for simpler designs, smaller sizes, and lower component counts, particularly as many smartphones move to integrate front- and back-facing cameras.
Mobile phone cameras will increase from approximately 1.6 billion units in 2011 to more than 2.2 billion units in 2015, representing 92 percent of mobile phones worldwide, according to Gartner Inc. The market research firm also found that an additional 15 percent of phones would have two cameras to take portrait photos or to enable video chat.
New LED Photo Flash Drivers for Smartphone Cameras Improve Image Quality - [Link]
Zak Kemble writes:
While working on an update for my CPU Usage LEDs project, I thought why not just make it into a universal RGB LED controller? The CPU Usage LEDs controller took a value between 0 and 255, worked out what colour it should be and then fade to that colour. This was very limiting; changing what colours it used and how it fades required a firmware update. With this universal RGB LED controller the host software does all the work and the controller is simply told what brightness the red, green and blue LEDs should be. To make it as easy as possible to interface with the controller I created a library which deals with all the LibUSB stuff.
AVR USB RGB LED controller - [Link]
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]