Maximum PC

Holy crap that's a ton of information. Sorry I haven't really been in the forums too much lately (Just finished my last final a couple hours ago).

I'm thinking that I should probably start simple and get it so that I can turn the lights on and off, then probably start writing some code etc. I think setting up any circuits etc should be easier (at least for me) than writing the code. I'll probably be writing most of this in linux (Ubuntu 9.10) as stuff like this just seems to work better than in Windows.

That parallel port relay board looks pretty cool too. I was thinking that I could basically make one from scratch that could be able to control like 128 relays or something so that I could hook up all kinds of stuff and control it with the computer.

Start simple then. Look at the kernel driver code I posted and try to understand what it does. Build the pulser board I did. See if you can put the two together. That is about as simple as it gets as far as parallel port interfacing goes.

When I built this 3.5 years ago I bought everything at the shack. You could order online for cheaper.

Parts list

• 8 LEDs
• 8 Resistors (unless you are using 5v tolerant LEDs)
• Desired length of Cat5 cable
• 25 Pin Male D-Sub Connector
• Some breadboard
• Length of wire for the ground (if using cat5 cable).
• Solder and soldering tools.

I have a soldering station but you can get a simple soldering iron for $20. However if you plan to be serious about it, spend the $100+ for a nice soldering station. Bonus if it has a de-soldering pump on it too. Now you can skip the D-Sub connector, cat5 cable, and wire IF you cannibalize a standard parallel cable. It was easier to do it this way as I found that hacking off the end of a parallel cable was a bit cumbersome to work with.

You may want to get something like this for prototyping first though:
http://www.radioshack.com/product/index ... Id=2734155

btw, grats on your finals.

I took a wimps way out. Since I have a small mountain of old printer cables (DB25 to Centronix 36) and some cutters I whacked off the 36 pin end of one of them.

My next problem was a system with a stock parallel port. The card was a dismal failure for the software I was trying to run. Hell I forgot about a few other machines lying around here. My old Dell Workstation before I built my new workstation fit the ticket so I dragged all 70 pounds of the beast out of the corner. Booted right up in XP for me.

I installed the software I mentioned earlier that went with the relay card and away it all went. I could toggle each data line without a hitch. Interesting the data highs were about 3.4 volts on this system. My new workstation has 5 volts off that card I installed. Anyway, things worked.

The idea behind the relay card link wasn't just the software but the complete schematic was in the pdf file on the web page.

I may continue to screw with a Windows approach but do admit that Linux is a more viable approach since working in Linux you have a straight shot at the parallel port.

There is really no limit to what you can interface to the port as to Relays, Triacs and whatever to control whatever. You have 8 data bits which can be fanned out to 255 whatever with a small mountain of chips.

When soldering, just remember the bigger the blob the better the job.

Ron

Nooooooooooooooooooooo.....

lol

I do have a few higher end Weller controlled heat stations here but the pencil I use most often is a Radio Shack plain pencil with two settings which does fine for most soldering applications. I think it was about $12.95 and the tips are something like 2 for a buck.

On another note I have had some luck outputting from the parallel port using VB. Better luck in Windows XP than Vista.

Interesting is what I found earlier holds true. My old workstation outputs 5 Volts on the data lines while every newer machine outputs about 3.4 Volts.

Ron

Are there any lines on the port that are 5v? If it is a constant 5v pull-ups will take care of the logic issue.

Nope, I am looking at them with similar to a logic analyzer. Really doesn't matter much as if I were to actually use the signals I would use a buffer in there right off the port.

This should be a slow workweek (why I like being in there over the holidays) so maybe I can experiment more. I won't be as beat up when I get home.

Anyway, I would likely run with an octo-buffer or I have a small mountain of 2N2222 transisytors which would make for great drivers off the port at literally a few cents each.

Since I wanted to work in a Windows environment my biggest problem is getting things to work primarily on Windows Vista. Haven't even screwed with Windows 7.

Ron

I will have to try to get some code together for Windows Vista/7. I am pretty sure I can do it.

I guess my question is even if you buffer it, won't you still want to have as close to the ideal 5v as possible?

Nifty chart: http://www.interfacebus.com/voltage_threshold.html

I guess it doesn't matter as long as it is above 2.2v

[source]

Damnit... I really want to play with this now...

Crash, there is no doubt in my rabbid ass mind that you could write something. Most of what I have seen seems to be built around that impout.dll file and from what I gather the .dll has been improved to address 32 and 64 bit Windows systems. Stuff written primarily in C# too or variants of C.

No, it isn't all that important the output lines be a true 5 volt TTL level. Really the only time that the actual voltage plays into things is dependent on what we are driving with the data lines. If for example we wanted to use an optocoupler device to drive a triac knowing the forward diode current and voltage drop would be important as to coming up with a series resistor. Pretty much a matter of what you want to interface to from the port. That is how I see it anyway. I have been screwing with some interface circuits.

Once Christmas is behind me I'll have more time, especially over New Year's weekend.

Ron

Looks like we might have a winner for Vista and 64bit systems!

http://www.highrez.co.uk/Downloads/InpOut32/default.htm

I saw that but have yet to try it. Having survived a trip to Columbus for Christmas and having picked up the dogs from the puppy hotel finally back here in Cleveland and the laptop put away.

I want to get back to my experimenting with the parallel port outputs.

I have also been thinking about the serial port since the old parallel port seems to be a dying item anymore. I am busy at work this week for three days then I get a 4 day break (Happy New Year). So hopefully I will have some time to screw with this stuff.

Ron