LEDLoad is a device and software designed to controll two LED’s from your computer case. It uses modern tri-color LED’s that change color according to the computer processor load. So the only modification you need to make is to replace the original case LED’s with the tri-color ones. The device shows Blue for idle and gradients light blue, green, yellow, orange, and finally red indicating high CPU load. If the circuit loses communication with the software it flashes RED thus letting you know that the system has crashed or there is something wrong. The hardware is implemented by using a AVR ATMega88 microcontroller. The firmware is based on a software implementation of the USB 1.1 protocol. You can get the schematics and source code from the link below.
LEDLoad – controller for computer case LED’s: [Link]