Controlling things with the parallel port

[joel]

I have read a document on controlling led's with a parallel port. I
plan on using the led's to make an optio isolator connected to a relay
to control things around the house. first off, i was wondering if
anyone knows of a book that covers things at a basic level like this
and secondly a parallel port can only control 8 devices, is it cheaper
to use multiple computers or is there perhaps some type of system out
there that will let me control more?

thanks for any input

 

[John Jardine]

joel <jjshoe@hotmail.com> wrote in message
news:2cc16b82.0308210920.7ca6c688@posting.google.com...

I have read a document on controlling led's with a parallel port. I
plan on using the led's to make an optio isolator connected to a relay
to control things around the house. first off, i was wondering if
anyone knows of a book that covers things at a basic level like this
and secondly a parallel port can only control 8 devices, is it cheaper
to use multiple computers or is there perhaps some type of system out
there that will let me control more?

thanks for any input

You only need 1 computer.
A method is to just use 3 of the port pins (eg D0-D1-D2), to -serially- send
a set of on/off bits to one or more 74HC595 i.c.'s.
Each 74HC595 chip can control 8 outputs. 4 chips (say) could control 32
optos.

For example,
D0 serially puts out the opto-led, ON or OFF bits to the 74HC595's
D1 makes a clock pulse for each of these serial opto-led bits.
After all the data bits are sent out then D2 is set high then low, to tell
the chips to latch the sent data onto their output pins.
(Use optos that have low current LEDs to avoid loading the 74HC595 o/p pins)
regards
john

 

[the Wiz]

Check Jan Axelson's site www.lvr.com and her book on interfacing the parallel
port.

It's relatively easy from DOS and Windows 3.x, but you need additional interface
software (drivers, etc) for Windows 95 and higher.

You might also consider a separate controller board, such as the one from
http://www.boondog.com/ (click on the Products link).


jjshoe@hotmail.com (joel) wrote:

I have read a document on controlling led's with a parallel port. I
plan on using the led's to make an optio isolator connected to a relay
to control things around the house. first off, i was wondering if
anyone knows of a book that covers things at a basic level like this
and secondly a parallel port can only control 8 devices, is it cheaper
to use multiple computers or is there perhaps some type of system out
there that will let me control more?

thanks for any input

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Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter atat mindspring dotdot com. Fix the obvious to reply by email.

 

[cpemma]

joel wrote:

I have read a document on controlling led's with a parallel port. I
plan on using the led's to make an optio isolator connected to a relay
to control things around the house. first off, i was wondering if
anyone knows of a book that covers things at a basic level like this
and secondly a parallel port can only control 8 devices, is it cheaper
to use multiple computers or is there perhaps some type of system out
there that will let me control more?

The method John outlines has a circuit at DiscoLitez:

http://discolitez.com/download.shtml and there's the software too.

 

[Si Ballenger]

On 21 Aug 2003 10:20:42 -0700, jjshoe@hotmail.com (joel) wrote:

I have read a document on controlling led's with a parallel port. I
plan on using the led's to make an optio isolator connected to a relay
to control things around the house. first off, i was wondering if
anyone knows of a book that covers things at a basic level like this
and secondly a parallel port can only control 8 devices, is it cheaper
to use multiple computers or is there perhaps some type of system out
there that will let me control more?

thanks for any input

I've got the below page showing how to use the parallel port to
control my homemade webcam video switchers using "notepad"
software. The "El Cheapo #3" setup could control ~40 things one
at a time, and is made totally from Radio Shack parts. If you
really want to be a parallel port control freak, the bottom link
shows how to individually control up to 380 strings of christmas
lights via the parallel port.

http://www.geocities.com/zoomkat/ppswitcher.htm
http://tinyurl.com/ksbc

 

[Bob Masta]

On 21 Aug 2003 10:20:42 -0700, jjshoe@hotmail.com (joel) wrote:

I have read a document on controlling led's with a parallel port. I
plan on using the led's to make an optio isolator connected to a relay
to control things around the house. first off, i was wondering if
anyone knows of a book that covers things at a basic level like this
and secondly a parallel port can only control 8 devices, is it cheaper
to use multiple computers or is there perhaps some type of system out
there that will let me control more?

thanks for any input

The parallel "port" includes 3 separate I/O ports: Data, Status, and
Control. To control more than 8 bits, you can use the Control port
to provide 3 additional bits directly (it's got special uses for some
bits). For lots more outputs use those 3 extra bits as address bits
to select one of 8 octal latches that are updated by the Data port.


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
Shareware from Interstellar Research
www.daqarta.com

 

[R. Steve Walz]

joel wrote:

I have read a document on controlling led's with a parallel port. I
plan on using the led's to make an optio isolator connected to a relay
to control things around the house. first off, i was wondering if
anyone knows of a book that covers things at a basic level like this
and secondly a parallel port can only control 8 devices, is it cheaper
to use multiple computers or is there perhaps some type of system out
there that will let me control more?

thanks for any input
-------------------

Multiplexing. Learn digital.
-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public