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parallel port

I've been reading James "J.J" Barbarello's book, Real-World Interfacing With Your PC, 2d ed., and now I'd like to try to actually do something. The first thing one has to do is to make a "break-out cable", which he describes early in the book. As it happens, I found a discarded printer several months ago and scavenged its printer cable, one end of which plugs into the PC. So, I think I don't need to build a break out cable according to his prescriptions, I just have to cut the cable somewhere. If I had any way to make use of the end that goes to the printer, I wouldn't need to cut the cable at all. It looks like it is supposed to receive some kind of card edge. Maybe if I had also scavenged the printer, I would have been able to extract its card and remove all the electronics and use it for my own experiments. Without it, I'm not sure what to buy and for how much to use the cable intact.

Barbarello is very specific about the lengths he wants one to use to make the break-out cable and the jumper cable one needs to connect the break-out cable to the breadboard one is using for experiments. He wants

4 inch lengths of #22 wire to make the break-out cable from a DB25 connector and he wants a 5 inch length for the jumper cable. This seems to take nothing into account about the actual distances between the computer and the breadboard. I know from experience, from which I unfortunately did not learn enough, that funny things can happen when one uses long wires in digital circuits. So, I'm allowing for the possibility that Barbarello really means that the wires should be fairly short. On the other hand, the printer cable is clearly much longer than that, but it is much more carefully designed and maybe that matters.

I also looked at another book, Parallel Port Complete, by Jan Axelson, but it seems to be mostly concerned with software and gives almost no guidance in actually building anything. Also, it seems to be oriented towards Windows, while Barbarello is oriented towards DOS, which I prefer.

If there are more interfacing books with simple parallel port projects, I'd also be interested in looking at them. Ultimately, I'd like to build some kind of simple apparatus for simple experiments in areas other than electronics (safe stuff that can be done in the home) and have it controlled and monitored by the computer via the parallel port. At the moment, I'm keeping an open mind about what I'd like to do and would be glad to know about books that contain specific projects that can be done very cheaply. Barbarello mostly discusses using DAC's and temperature sensors.

--
Ignorantly,
Allan Adler 
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
Reply to
Allan Adler
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Don't worry about the length of the printer cable. The parallel port isn't really what you would call "high-speed", and the normal PC parallel port can handle cable lengths of 15 feet or more. Just cut the cable that you have to the length you need and you should be just fine. Since this is an unusual manufactured cable, you will obviously need to make sure that all the wires you need for your experiments are wired into the cable. Some of the early printers (Radio-Shack, Commodore, etc.) didn't have the standard Centronics interface that more modern printers have used.

Cheers

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

If a mute swears, does his mother wash his hands with soap?
Reply to
DaveM

I've got some simple parallel port stuff at the below links that might be of interest. For cabling, I just use a male DB25 connector and four conductor cat3 telephone wire.

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Reply to
Si Ballenger

the plug that the other end goes to is a centronics 36-way plug should you want to purchase one (might be easier to grab a discarded printer)

he probably had it short to save money, unless he's running that port at a really high data rate length won't be much of a problem. (not with breadboard projects atleast)

I've seen printers on the end of 30m ribbon cables and those round cables are often superior to ribbon cables.

Bye. Jasen

Reply to
jasen

Wrong way around. Radio Shack ALWAYS used the standard Centronics interface - they made their standard from Centronics' design. It was IBM who stuffed it all up by using the standard DB25 serial connector for the printer and a reversed connector for the serial port. They also misconnected some of the wires making it even less like the standard. Curse their black hearts.

Reply to
Homer J Simpson

Coincidentally, I just found an electric motor in a dumpster. Assuming it still works and I can figure out how to use it (I've never done this before), one project can be to control this motor from the parallel port. It was sitting next to a fan enclosure in the dumpster, so I'm guessing it was used to turn the fan. It has something on the spindle that probably is inteneded to hold a loop to turn the fan. It's dirty and heavy and I found the following information on the body of the motor (= signs mine for readability):

Howell Motors 6146 HP=3/4 PH=1 DUTY=CONT. FRAME=N56 FRQ=60 RPM=3450 VOLTS AMPS S.F. L 203 230 4 . 5 1.25 V H V

CODE=L C^o RISE=40 (C^o means C superscript o, as in (I think) deg C).

38P11-5301-1 Thermally protected AUTO 70377900 SF AMPS 5.0 86H

I think the AMPS field is 4.5A, but maybe it means between 4 and 5 amps.

Before using it, I'll probably need to mount it and probably on a thick board, but I don't know yet how strong it needs to be and what that implies for the choice of board. I don't think I can tell the computer to control the motor until I know how to do it myself. After that, there is the problem of setting up the circuits to power and control the motor, but one thing at a time.

--
Ignorantly,
Allan Adler 
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
Reply to
Allan Adler

Thanks.

OK

What do you mean by the standard Centronics interface?

--
Ignorantly,
Allan Adler 
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
Reply to
Allan Adler

Thanks. I'll try looking at them on a better computer than I have. I took a look with my browser on my computer and Netscape hung while I was trying to bookmark them. Then the whole computer hung. When I rebooted and the PC tried to correct the errors due to having failed to unmount the disk cleanly, I got an unusual message about how the file system had become inconsistent. I had to log in as root and run fsck manually to correct the problem. I'm not saying it is your fault, just that my machine and its browser seems to have some deficits.

--
Ignorantly,
Allan Adler 
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
Reply to
Allan Adler

Commodore used the IEEE-488 interface for their early computers, and their serial version of the IEEE-488 bus in the Vic 20 and up, till they introduced the Amiga line

The original Centronics interface called for twisted pairs for the data lines, but I don't recall any personal computer that actually stuck to that requirement. I had a Centronics service manual that had a whole section on their parallel port interface. They weren't arrogant enough to name it after themselves.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
Reply to
Michael A. Terrell

A 3/4 horse motor is a honking big motor and can only be on or off. No other control is possible.

You'd do better to pick up a Radio Shack Color Computer (about $10) and look at some of the interfacing books on various sites: -

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They'll have practical projects and how-tos.

Reply to
Homer J Simpson

and its most likely no good..

--
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5
Reply to
Jamie

Let me take these points in turn. (1) Who will sell me a Radio Shack Color Computer for $10? Will it cost more than $10 to ship it to me? (2) Does anyone else think that I should get a Radio Shack Color Computer? (3) The first website deals with emulators for TRS computers. If I ran such an emulator on a PC running Windows (which would not be one of my PC's, which all run Linux), and ran software for interfacing a TRS through its parallel port, would that software run under the emulator and would the project thereby work on the PC in question? (4) I could be mistaken, but I would think that the most useful information to be extracted from the practical projects and how-tos would be adaptable to the PC's I'm actually using. I'm planning to use FREEDOS at first and Linux if I can ever get an overview of how it talks to the parallel port. I'm somewhat optimistic that I can since I once downloaded some software for Linux that does just that and it said that it was working. Also, I have the book, Linux Device Drivers, 2d ed, and it has a project of talking to the parallel port in one of the chapters. Anyway, one the premise that the information in the TRS guides to interfacing and projects is exportable, I don't think I need to get a Radio Shack Color Computer.

Apologies if I didn't realize you were joking.

--
Ignorantly,
Allan Adler 
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
Reply to
Allan Adler

eBay

Not joking. Coco's have been used for all sorts of things like this. IIRC, someone used one to replace a $20,000 video controller. There are books on interfacing them, which is real easy to do. Even an old 8088 PC is a bitch in comparison, and that is when you could buy boards to do this.

I also recall a Model 100 used to control a road resurfacing machine. Ports are handy.

Reply to
Homer J Simpson

OK. I'm not ready for ebay. I don't know if I ever will be. On the other hand, I did once look over the vendors at ebay and found one with a good reputation and made a deal with him for an item that he didn't happen to be auctioning. So, maybe I'll try something like that.

Thanks very much for telling me about this.

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Ignorantly,
Allan Adler 
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
Reply to
Allan Adler

have a look at the "linux-coffee howto" a good introduntion to ad-hoc hardware and the parallel port under linux.

--

Bye.
   Jasen
Reply to
jasen

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