This page describes how you can use keyboard LEDs to monitor the status of a linux server. This is very handy have a number of linux servers at home, and typically want to be able to monitor the status of them remotely.
All my servers run various flavours of linux, and typically run headless (ie, no monitor/keyboard/mouse), but are accessed remotely via SSH and/or HTTP.
While it would be possible to connect a small LCD to a server, and write some software to display status information on the LCD, this required a lot more effort and expense than I was prepared to expend.
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.
The relatively long PS/2 cable on most keyboards is ideal for remotely mounting the LED display remotely from the linux box.
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