Blog Archives
Posted on 17 May 2008
This page describes how you can use keyboard LEDs to monitor the status of a linux server.Martin writes:Instead, I use some software running on each linux box, to toggle the keyboard LEDs on and off to indicate status information. Instead of having a full-size keyboard plugged into each server, I disassemble the keyboard, and remove all the unnecessary components, leaving just the circuitry required for controlling the LEDs. The standard LEDs are replaced with new LEDs that are easier to mount, and an additional power LED is added, allowing the three LEDs (NumLock, CapsLock, ScrollLock) to be used to indicate various status information. [more]
Posted on 17 May 2008
For most of my LED applications a very special circuit was designed to run the LEDs at a “constant current”. This provides a constant amount of power to the LEDs and also provides a constant amount of light for a longer period of time. This circuit also allows the LEDs to run on almost any normal voltage above 4 volts. This means you can use multiple sources of power for the same light, a few AAA batteries, or even a car battery .[more]
Posted on 14 May 2008
35 Pixels writes:This thing operates just like a real firefly. Initially, it flashes a firefly song for 30 minutes. Then, it samples the ambient light level every minute. It waits for daytime, and then waits for dusk. Then the cycle starts over with the firefly flashing.[more]
Posted on 11 May 2008
The project uses a PIC16C84 to monitor 4 NC alarm inputs that when triggered, activates an output relay. The first zone triggered is illuminated with a solid lit LED, while the second and subsequent zones are indicated with a flashing LED.This project serves as a complete, although relatively basic introduction to digital electronics, PIC microprocessor programming and interfacing techniques.[more]
Posted on 08 May 2008
The goal of this project was to develop 3D spinning mechanism capable of displaying smooth video or static images. The device uses a spinning ring with tri-color LEDs inside, and relies on precise angular sensing and persistance-of-vision and to create the effect of a spherical display surface. Although the system consists of only a single ring of LEDs, the high rotational speed makes it possible to display any combination of red, green, or blue pixels along the surface of the resulting sphere. (3-bit color depth!) [more]
