Re: [CAD_CAM_EDM_DRO] Simple Parallel Port controller

Scott Riddle wrote:

> I am looking for some help to use my parallel port to turn off and on a
> small relay switch. The device I want to control will shut off automatically
> after 1 cycle but it needs a 1 second ON switch to activate it. What I am
> doing is turning a small motor on and it will turn one revolution and then
> stop when the cam lobe on the pulley hits the switch lever to stop it. I
> need the computer to turn the relay on to start the motor moving. The motor
> is just a plain motor 12V not a stepper or servo. I will have the final
> drive slowed way down with a pulley so the switch cycle will take 3-4
> seconds. I have seen some simple controller boards for small servo motors
> for about $50 but All I need is a Off and ON switch. I would appreciate any
> help.

You can get DC solid state relays. Digi-Key sells them, for instance.
You can connect the SSR to the parallel port directly. It works best
if you supply +5 V from a spare disk drive power connector, or from the
game port (pins 1,8,9, and 15 are +5 V). Use the parallel port bit to
drive the pin you are using to ground to turn on the LED in the SSR.

Jon