Simple Parallel (Printer) Port Interface

Schematic

Parallel Port Pin Assignments

Parts

Part Total Qty. Description Substitutions U1, U2, U3 3 74LS367 Buffer IC 74367, 74HC367 MISC 1 Case, Wire, Sockests, 18 Pin Socket (For Output), 25 Pin Connector (For Parallel Port), Ribben Cable

Notes

1. I built the interface on a piece of universal solder board due to the large number of wires that must cross. It is also much easier to fix mistakes then on a PC board. I also used a 25 pin crimp connector to connect it to the parallel port. 26 conductor ribben cable was used to link the connector to the board.
2. This interface only offers 5 inputs (on some computers it may be less). For more inputs, see Computerize Your Room/House. If you choose to use the inputs, remember that the voltage level can not exceed 5 volts or fall below ground.
3. This circuit is TTL and therefor must be powered by no more then 5 volts.
4. You can download control software from my files section.
5. For more information on programming the parallel port, see Programming The Parallel Port In QBasic or Programming The Parallel Port In Visual Basic.