The parallel port on my vintage laptop can source enough current to light up a few LEDs. With this simple circuit, I continue to improve my soldering and PCB organization skills.
The LEDs are driven by a simple program running under my own homebrew operating system, Snowdrop OS.
If you use the materials on this page, or any other page on this web site, you do so at your own risk. They are provided "as is". No warranty is provided or implied. I neither guarantee that the materials will work, nor that they will not be harmful in any way.