Computer Control and Monitor

LED connected from pin 5 to ground (pin20)


If you are interested in sending a tiny current out of your computer, it is possible to do this through the parallel port.

Caution! It is possible to damage your computer.
This project requires advanced knowledge of electronics and computer hardware.

This site has a diagram of the pinouts of a standard 25 pin parallel port:

Writing code in Visual Basic to support this project requires the installation of a DLL that will give access to the port.
Download and install  "inpout32.dll" under "Programming Tools" from this site:

This code supports VB5, create a form with two command buttons and a text box.
Make sure "inpout32.dll" is copied to System and System32.

When completed, clicking "On" makes a tiny current available between pin 5 and ground.


Private Declare Function Inp Lib "inpout32.dll" Alias "Inp32" (ByVal PortAddress As Integer) As Integer

Private Declare Sub Out Lib "inpout32.dll" Alias "Out32" (ByVal PortAddress As Integer, ByVal Value As Integer)

Private Sub Command1_Click()

Text1.Text = "On"

Out 888, 8

End Sub

Private Sub Command2_Click()

Text1.Text = "Off"

Out 888, 0

End Sub