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9 Feb 2012

freecircuits.org writes:

This simple LED tester consists of a current source with a potentiometer that can be used to adjust the current. The current source is implemented using a type TL081 opamp. The output current of the opamp flows through the diode and R2. The voltage drop across R2 is fed back to the inverting input and compared with the reference voltage, which is set with R1 and applied to the non-inverting input. The adjust- ment range is approximately 0–30 mA, which is suitable for testing all normal LEDs. If you wish, you can connect a multi- meter across the LED to measure the voltage on the LED. For the power source, a good option is to use a small laboratory power supply with the output voltage set to 5 V. It is convenient to fit the potentiometer with a scale so you can see directly how much current is flowing through the LED. In order to calibrate the scale, you can temporarily connect an ammeter in place of the LED.

Simple LED tester circuit - [Link]

8 Feb 2012

Richard Comerford writes:

The first LED replacements for 60 W incandescent bulbs are now appearing on shelves in local stores across the United States. Although current U.S. law will phase out only 100 W incandescent bulbs in 2012, one can easily find replacements for incandescent bulbs of other wattages – 15, 25, 40, 60, and 75. The initial cost of the LED bulbs is relatively high, but they more than pay for themselves over time with their longevity and energy savings.

The LED bulb that has received the most attention so far is the AmbientLED Model 12E26A60, a 12.5 W, 800-lm replacement for 60 W incandescent bulbs made by Philips Lighting (Figure 1). It is similar in configuration to the bulb that won the U.S. Department of Energy’s first Bright Tomorrow Lighting competition, or L Prize. It was also declared a standout among the CFL and LED bulbs in lamp and ceiling fixture tests conducted by Consumer Reports magazine.

Inside the New LED Retrofit Bulbs - [Link]

3 Feb 2012

dangerousprototypes.com writes:

Mashiara designed an I2C controlled 4×4 RGB LED matrix. He uses 3 PCA9635 I2C-to-PWM drivers with 16 PWM outputs. Each IC controls a different basic color of the LEDs.

The up-side to this design is that all of the drivers are on-board, and only control signals are needed to manipulate the matrix. The down side is that his design requires 4 layers to route, and 4 layer boards are quite expensive to make.

I2C controlled 4X4 RGB LED matrix - [Link]

3 Feb 2012

This blog demonstrates how to drive a bi-color LED, or any 2 LEDs, by using only one microcontroller pin. Sinking or sourcing current from the LED selects which one will light up. Setting the pin as input turns both LEDs off.

Alternating between 0,1, and high-Z, both LEDs are fully controllable and even dimmable. The article also explains how to calculate the resistor values to get the desired current for the LEDs. The only drawback to this circuit is that consumption will increase because the voltage divider requires current even when the LEDs are off. [via]

Driving a bicolor LED from a single output pin - [Link]


3 Feb 2012

Having been disappointed by the generic offering of Christmas lights with small customization options, he decided to make fully customizable light decoration.

Small PIC12F609 MCUs along with RGB LEDs are placed on a board and daisy chained over a 3 wire cable. A master MCU is placed on one end of the cable and controls the color of the lights individually by sending addressed data over the wires. [via]

Christmas lights with a MCU in each bulb - [Link]

3 Feb 2012

Don built an Amblight for his home theater PC. He put together this tutorial describing his build of a multichannel Arduino-based Ambilight. He estimates the BOM at $40 (in addition to the Arduino). [via]

The bill of materials include 6+ ShiftBrites (your call, I wouldn’t do less than 6 though), a printed circuit board, wire, and headers. Additionally this will require all of the components needed to get over 0.5 Amps at 5.5-9V DC on to the board to drive the ShiftBrites; this cannot be reasonably done over USB power. My ultimate goal here is to give others some ideas on how to go about this project for less money than it would cost to essentially buy everything in a kit. I went in to this trying to be resourceful and I feel pretty good about how it turned out.

DIY Arduino Ambilight using ShiftBrites - [Link]

31 Jan 2012

To achieve a more aesthetic panel of your device, you can use flat top LED diodes Kingbright!

We´d like to focus your attention to well-proven flat top LED diodes intended mainly for indication on various controlling and indicating panels. In comparison to standard types with a half-ball top, these types offer a significantly more aesthetic solution when used in front panels.

Advantages / Features:

  1. aesthetic solution for front panels
  2. available in 5mm, 3mm and 2mm diameters
  3. very good visibility even from angles
  4. low power consumption

From the most used cylindrical types, we keep in stock types with a diameter of 5 mm, 3 mm, as well as miniature ones with a diameter of only 2 mm. All offered types have diffused plastic packages, thus they feature a good visibility even from high viewing angles.

Don´t let LEDs stand out of the panel - [Link]

30 Jan 2012

Andrea Belloni writes:

We realized this project for the “Arduino Day” in Rome 14/04/2011. For it we used two JeeNode (Arduino variant with wireless module on-board), one Rainbowduino + RGB LED Matrix and one PC with Processing. The Processing sketch generate the “plasma” animation and sends the images stream to the first JeeNode via serial port. This JeeNode receives the images and sends it to the second JeeNode via wireless link. The second JeeNode receives the images and sends it to the Rainbowduino + RGB LED Matrix via i2c. More details on the blog’s post (for the English version scroll down).

Wireless pixels - [Link]

28 Jan 2012

A very powerful and bright LED designed to be run on high current. Can be driven to 2800 mA and gives a light flux of 700 to 900 lm (400 lm at 1400 mA). Colour temperature 6300 K and beam angle 130°.

Available as a loose component as well as mounted on STAR PCBs.

Z-Power LED P7, 11.8 W  – [Link]

 

28 Jan 2012

An SMD LED for direct drive with 120/230 V alternating current. The LED consists of two separate coils which are connected in parallel at 120 VAC, and in series for drive with 230 VAC. Available in cold white and warm white versions with a light flux of 360 lm and 280 lm respectively.

230V AC Powered LED - [Link]



 
 
 

 

 

 

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