Notes on LEDs. LED Parts LEDs come in all shapes and sizes, but the 3mm T-1 or 5mm T-1¾ are probably the most common. The die is an itty bitty cube of semiconductor, the composition of which determines the color of the light given off. It sits in the bottom of the die cup, which has reflective sides to reflect the light emitted by the die toward the dome end of the LED. The epoxy body is shaped to act as an inclusion lens and focus the light into a beam. LED Color Visible LEDs LED colors are often given in "nm", or nanometers, which is the wavelength of the light. Notice the temperature given in the upper right corner of the graph - LEDs emit slightly different colors at different temperatures. Infrared LEDs The infrared band can be divided into Near Infrared (NIR) and Far Infrared (IR). Infrared LEDs are sometimes called IREDs (Infra Red Emitting Diodes).
Ultraviolet LEDs 400 nm is a pretty common wavelength for UV LEDs. White LEDs White light is a mixture of all the colors. LED Brightness Confused yet? Back. A dark detecting circuit for your jack-o'-lantern. Here’s an inexpensive electronic circuit that you can build to put in your Jack-o’lantern. It provides power to drive a few LEDs at night, and automatically turns them off during the daytime. It’s a simple and automatic dark-detecting circuit that you can use to for your very own photosensitive pumpkin. Our pumpkin project is closely related to the minimalist dark-detecting LED circuit that we showed previously. In that project– basically an LED throwie with a sensor– a phototransistor controls a single LED. While the minimalist circuit is marvelously compact and simple, it is limited both in terms of sensitivity, LED driving capability, and extensibility.
It can drive a single red or yellow LED from a lithium coin cell– but that’s it– and it requires fairly bright light (e.g., direct sunlight) to turn off the LED. So our new dark-detecting circuit is only almost as compact or simple, but is much more sensitive, and is capable of driving several bright LEDs for your Jack-o’lantern. Lighting Effects with LEDs. LOOK at the top row of pins. The third from the right is marked “CK” or “Clock”. BOTH the resistor and capacitor go to this pin. It’s a bit of a tight fit, but not hard to make. If you wish, you can use wire wrap to connect this pin to one leg each of the resistor and the capacitor. Or you can use very fine tip needle nose pliers and carefully fold a wire from the resistor and the capacitor around this pin, and then solder.
Gently straightening out the pin away from the body of the chip may make this step easier. As usual make sure these wires don’t touch any other pins. NOW, connect the other wire from the resistor to the pin marked “out 1”, the second from the right. Sometimes I just use the wire wrap to connect the resistor and capacitor, especially if I have to cram the circuit into some place tight. O.K. But how do you tell if it’s “alive” and functioning? How fast will things blink? AND each pin goes from ‘positive’ to ‘negative’ rather than from ‘on’ to ‘off’. Experiment. Led circuits page. 1.5 Volt LED Flashers The LED flasher circuits below operate on a single 1.5 volt battery. The circuit on the upper right uses the popular LM3909 LED flasher IC and requires only a timing capacitor and LED.
The top left circuit, designed by Andre De-Guerin illustrates using a 100uF capacitor to double the battery voltage to obtain 3 volts for the LED. Two sections of a 74HC04 hex inverter are used as a squarewave oscillator that establishes the flash rate while a third section is used as a buffer that charges the capacitor in series with a 470 ohm resistor while the buffer output is at +1.5 volts. When the buffer output switches to ground (zero volts) the charged capacitor is placed in series with the LED and the battery which supplies enough voltage to illuminate the LED. The LED current is approximately 3 mA, so a high brightness LED is recommended. AC Line powered LEDs The lower circuit is an example of obtaining a low regulated voltage from the AC line.
LED Traffic Lights 72 LED Clock. Candle LED with Simulated Flicker. Hello everyone! After finding out about the Arduino I ordered one. And I don't think I've unplugged it from my computer since! Well I have done many small project and such so far, I'm finding a wealth of information all over the net. But by far this Forum as been one of my favorite resources. Here's the code: ( Excuse any mess. /* * Wind Switch with Flickering LED * by Electrick_RWM (dragoonx@gmail.com) * Date Oct 18 2007 * Makes the LED on Pin 9 glow sloftly and when Switch or "Wind" Switch is toggled it flickers!
Void setup() { pinMode(ledPin, OUTPUT); // declare LED as output pinMode(ledCandle, OUTPUT); // declare Wind led as output pinMode(inputPin, INPUT); // declare Wind Switch as input} Here's a Picture of the board itself, as you can see, pretty simple:: Well I hope someone out there can put the code and/or info to some use!