Re: using serial or parallel port for TTL input

<chad@xxxxxxxxxxxxxxxx> wrote in message
news:1132254545.707421.320160@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> HI,
>
> I would like to be able to use my PC to detect when a transistor is
> high. I have found several circuit designs on how to control a
> transistor from a serial or parallel port, but none for detecting the
> state of transistor.
>
> I want to build a laser beam break detector like this
> :http://repairfaq.ece.drexel.edu/sam/laserexp.htm#expbbd
>
> When the beam is broken, a transistor will be triggered and I would
> like the computer to sense when the line is high.
>
> Can this be done with a serial or parallel port?
>
> thanks
> chad
>

Chad, since you're obviously a bit uneducated about controlling a parallel
port, I suggest you look at Jan Axelson's web site at www.lvr.com
Jan has several books on using the parallel and serial ports on a PC to
control external circuitry, as well as using these ports to monitor external
events. Check out the parallel port links and you'll learn a lot about
what you're trying to do. A copy of her book Parallel Port Complete will
teach you more than you ever wanted to know about the parallel port.

Cheers!!!!
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the address)

Never take a laxative and a sleeping pill at the same time!!


.

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