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'Other' uses for a parallel port

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paul.brett

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Jun 20, 2007
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376
Location
Wisbech, CAMBRIDGESHIRE, UK
Hi guys,

I have almost completed a project to semi-automate some of the gizmos in my home-office using the parallel port of an old PC.

Basically, I can turn on/off up to 8 mains powered devices. The software is written in BASIC, and using RAPIDQ, I have made the program a CGI script.

All this means I can turn on/off the lamp/fan/laser-printer/ftp-server in my home-office from anywhere in the world. I have obviously password protected this particular CGI script, as it could be mis-used. I have to say, it is a hoot to be able to control stuff from the Internet.

If anybody is interested, I can take some photos of the unit, post a circuit diagram and even demonstrate it working (via a webcam).

PM me.

Paul.
 
Yeah, that's a nice use for some older but stable systems. A lot of folks I've seen use an Amiga 500/1000 or something for that sort of work.

One of the most amusing ones I saw back in the day was a guy who did have it publicly open to the internet where you could turn on and off the light in his bedroom, ring the doorbell, and (the best one) drive a toy RC car with a mounted (wireless?) camera on it.

He also had a cat. Obviously he noted "go easy on the cat" on his website. I got the car stuck when driving around the kitchen because I was able to get under the kitchen table but didn't realize there were wood bars going around to some of the legs of the table and sort of drove myself in without figuring out how to get out. I left and a few hours later I guess he found it (or someone else figured it out) and it was sitting back in the living room again. I tried to drive through a computer case (top of a mid-tower case) on the floor but realized whatever I was driving was a little larger than I thought so that didn't work either. I also recall getting stuck either under or nose in trying to drive under the couch for some reason.

The thought of coming home to a little rc car driving around on its own seems pretty funny to me though.

It was a java front end on the site (he wrote it himself from what I remember) however from there I guess it was some cgi scripts that communicated to a com or parallel port on the computer in order to interface with the other devices. I think all of them were working through RF integrated circuits or RF power plugs. I know he's still out there although I think he took the car off the page and it looks like he may have moved into an apartment or something (could be wrong) but the rooms I used to drive through seemed large.
 
Paul,

Just as a coincidence I purchased the "Handbook For Parallel Port Design" by James Barbarello. It's a good book, but I am looking for other references too - do you have any to suggest?
 
back in the days when you thought you were something if the second digit of your front panel "megahertz indicator" was lit up, I built a sound sampler to go on my parallel port. I recorded stuff into a block of external static rams, then clocked it in to files on the pc.
I then had an R-2R resistor D-A converter and could play the samples back out again. it was a bit fiddly, and you had to run a calibration routine on a new pc to find out how fast to send the samples out to get the pitch right.

In later years I've had hundreds of things attached to parallel ports both for sensing and driving stuff, Last time i used it in anger was to drive a test rig for microstepping stepper motors to get loads of sub-steps per step, by driving variable constant currents into the windings. I had 3 PICs on the end one for each winding, and one for counting the pulses from the opto encoder to see how well I was doing. it would self optimise over about 10 minutes, and then someone would send me an email, and it would all go to ****! dual booted to dos after that!

it's just a shame that the HAL gets in the way on new operating systems and you can't just in and out it any more.

I've started looking at the new "dos" variants for that reason.

Edit - I've just been censored! I wonder if Vbulletin hosts a chicken fanciers forum??
 
Censored by what?

If you want to dink with the parallel port under Linux, download the kernel source code and party on! The problem with that of course is the real-time aspect, as you mentioned. But I'm sure that with a dual core 2Ghz machine you can simulate the timings you get on an old XT. ;-0
 
"all to <male chicken>"

Yes it seems to be true about the faster the processor, the slower the machine becomes. just seems to get bogged down with more useless tasks.

However I've been experimenting with a 1Gig PIII running 32 bit Freebasic under DOS and it does seem to steam along a bit. One day my wife will stop beating me up for sitting in a little dark room concocting, and I'll get my project parallel port disk reader up and running.
 
I remember having seen some information about a LPT to ISA converter. It let you use any 8-bit-ISA card which doesn't need DMA (and runs under Windows 3.1, because a driver was needed).
I believe it would be quite easy to write a bus driver for *BSD, without needing any change to the drivers (Linux, unfortunately, would need them).

My new computer didn't get a parallel port, so I can't use my Epson LQ-200 printer anymore. ;(
 
I remember seeing external ISA bus things that connected to I believe a parallel port or its own card. I think Jameco sold something like that at one time.

Yeah, when I bought my last rig it has no serial ports at all, just USB and IEEE 1394. You can still buy Serial port PCI cards though. but I don't know how well that would work.
 
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