PC parallel port (LPT) and voltage - Home Automation

"joe" <mt@invalid.com> wrote in message
news:75ubd45b4hhrao47gudi68c4faro3ofp4g@4ax.com...
>I want to use my pc to imput data when a motion detector detects movement.
>
> I've read that LPT port can handle 5V. But what about current? I'd like to
> test
> with a small transformer. The transformer outputs 4.5V with 2.5A. Will
> that
> damage the printer port should should I cut the current with resistors?

Probably. Using opto-isolators is always a fine idea. But you'd do well to
search the web for articles on parallel port interfacing.

> >I want to use my pc to imput data when a motion detector detects movement.
I have some OLD but maybe useful stuff on parallel port HERE:
http://terryking.us/parport/

I agree about using opto-isolators. Learn that, and you can interface
about anything safely, for $1 or less....

On Fri, 31 Oct 2008 00:25:03 -0700 (PDT), TerryKing <terry@terryking.us>
wrote in message
<ec1a78ca-8b4d-4202-b53c-fee177d25e69@z6g2000pre.googlegroups.com>:

>> >I want to use my pc to imput data when a motion detector detects
movement.
>I have some OLD but maybe useful stuff on parallel port HERE:
>http://terryking.us/parport/
>
>I agree about using opto-isolators. Learn that, and you can interface
>about anything safely, for $1 or less....
>

Terry's write up on the hardware is helpful, but writing directly to I/O
ports is more complicated under modern windows ( W2K, XP, Vista) than under
DOS and Win9x.

Here's a detailed, step-by-step How-To for GUI-based programs to control the
parallel using Visual Basic 2005 Express Version (a free download from MS).
You can also just download the source code.

http://www.codeproject.com/KB/vb/Inpout32_read.aspx

The site that provides the required (also free) .dll file also has links to
parallel port programs and programming in Python and Real Basic as well as a
64-bit version of the .dll

http://logix4u.net/index2.php?option...age=0&Itemid=1
I agree that opto-isolation is highly desireable, even necessary depending on
the application. Here are links to interfaces:
http://www.epanorama.net/circuits/parallel_output.html

HTH ... Marc

Visit my updated Home Automation and Electronics Internet Porch Sale at
www.ECOntrol.org/porch_sale.htm

Marc_F_Hult
www.ECOntrol.org

Some old but simple parallel port stuff that will work on XP
machines.

http://www.geocities.com/zoomkat/status.htm
http://www.geocities.com/zoomkat/index.htm


On Fri, 31 Oct 2008 09:11:31 -0400, Marc_F_Hult
<MFHult@nothydrologistnot.com> wrote:

>On Fri, 31 Oct 2008 00:25:03 -0700 (PDT), TerryKing <terry@terryking.us>
>wrote in message
><ec1a78ca-8b4d-4202-b53c-fee177d25e69@z6g2000pre.googlegroups.com>:
>
>>> >I want to use my pc to imput data when a motion detector detects
>movement.
>>I have some OLD but maybe useful stuff on parallel port HERE:
>>http://terryking.us/parport/
>>
>>I agree about using opto-isolators. Learn that, and you can interface
>>about anything safely, for $1 or less....
>>
>
>Terry's write up on the hardware is helpful, but writing directly to I/O
>ports is more complicated under modern windows ( W2K, XP, Vista) than under
>DOS and Win9x.
>
>Here's a detailed, step-by-step How-To for GUI-based programs to control the
>parallel using Visual Basic 2005 Express Version (a free download from MS).
>You can also just download the source code.
>
>http://www.codeproject.com/KB/vb/Inpout32_read.aspx
>
>The site that provides the required (also free) .dll file also has links to
>parallel port programs and programming in Python and Real Basic as well as a
>64-bit version of the .dll
>
>http://logix4u.net/index2.php?option...age=0&Itemid=1
>I agree that opto-isolation is highly desireable, even necessary depending on
>the application. Here are links to interfaces:
>http://www.epanorama.net/circuits/parallel_output.html
>
>HTH ... Marc
>
>Visit my updated Home Automation and Electronics Internet Porch Sale at
>www.ECOntrol.org/porch_sale.htm
>
>Marc_F_Hult
>www.ECOntrol.org