The 8bi8 is a small self contained 8×8 bi-colour LED matrix toy. It has emerged after various prototypes. From here I want to create a new revision building on what I have learn from building this version.
8×8 bi-color LED matrix toy - [Link]
A very popular type of LED that has finally come about is the tri-color, RGB LED. The RGB stands for: red, green and blue since the LED is capable of displaying all three colors, independently. This means that an RGB LED can display any color of the rainbow. This is a powerful capability, but it also requires more control.
In this article, we shall look at how to build an RGB LED controller so that we have accurate and independant control over all three colors at any instant. The method of Fading LEDs via PWM will be leveraged for this design, since our goal here is quite similar, but with more control paths.
RGB LED Controller - [Link]
Ordinary LED flashers turn the LED on and off abruptly, which can get a little irritating after a while. The circuit shown here is more gentle on the eyes: the light intensity changes very slowly and sinusoidally, helping to generate a relaxed mood. The circuit shows a phase-shift oscillator with an adjustable current source at its output. The circuit is capable of driving two LEDs in series without affecting the current. The frequency is set by three RC networks, each of which consists of a 100 microF capacitor and a 22 kohm resistor. Operation is largely independent of supply voltage, and the average LED current is set at about 10 mA. The circuit adjusts the voltage across the emitter resistor so that it matches the base voltage of the first transistor (around 0.6 V). The phase shifting network gives rise to the oscillation around this average value. In the prototype of this circuit we used an ultra bright red LED.
Smooth Flasher circuit - [Link]
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]
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]
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]
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]
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]
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]
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:
- aesthetic solution for front panels
- available in 5mm, 3mm and 2mm diameters
- very good visibility even from angles
- 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]