Step 11 : Multi-Write Hardware Schematic


Here is the full schematic. Click on it to see the full (large) image. The parallel port control box in this how to is a multi-write configuration which means that each time a circuit is turned on or off, there are several clock cycles of data being sent from the PC to the box. In our scenario, each circuit state change requires 6 clock cycles.

Step 12 : Completed Circuit


Here is a photo of the wiring of the completed circuit. Most of what you see is the white wires going from the flip flop outputs to the 9-pin ports. There are 360 wires (9x40) to control 320 circuits.

Step 13 : 9 Pin Port


Here is a close up shot of one of the 9 pin ports and the wiring connections. Pins 1 through 8 are for circuits 1 through 8 and pin 9 is the ground.

Step 14 : Mounted in Box


This is a shot of the full circuit mounted in its box. Also, if you look real close at the bottom right of the image, you can see a red and black pair of wires (just below the parallel port cable). These wires go to a computer power connector which plugs into one of the PC's spare power connectors that you would normally plug into a hard drive or CDROM or whatever. These wires connect to the Vcc and Ground pins of all of the integrated circuits. This also gives a common ground reference for the IC power and the parallel port's ground.

Step 15 : Another View


Here is another picture before closing the controller box.