USB to Parallel?

As far as i know yes, I have such a device and it works fine.

But just to be on the safe side wait and see if anyone else comments

I've seen a few microprocessor programmers which have disclaimers buried down deep in the documentation that USB-serial adapters won't work, aren't recommended, etc. But I've also seen a few which say they will but that only models x, y and z have been tested and approved, etc.

I've tried them and found that they sometimes work, sometimes don't. Sometimes an adapter will work for me but won't work for other people using the same programmer & software. Weird.

My anonymous, non-prosecutable, unpaid advice is to go ahead and try it.

Even on a desktop where one can access the registers of the Centronix port directly one have to strip the operating system of unnecessary software to obtain sufficient speed.

Using a USB port may just remove the possibility of direct control resulting in unacceptable speeds..

Maybe you should consider using a PIC to drive the stepper controllers.

GA from me.

Your comment:-

You can buy a PCMCIA parallel port that would work, if you have a PCMCIA slot on your laptop.

is truly excellent.

I do believe that on some modern laptops there are also other possibilities with plug in cards....

The USB to parallel converters are very "iffy" as to whether they will work or not.....

Hi

Picaxe have an adaptor which works fine, I use it all the time. You have to make sure you use the same USB port each time.

http://www.rev-ed.co.uk/docs/axe027.pdf

Tony

Its a good bit of kit, but it is USB to SERIAL, not Parallel!!!!

Hi

Sorry Andy you're correct! I should have read the question properly.

This is not an answer but, there are a number of CNC driver boards available, run through a program called Mach3. Maybe get an old computer with parallel port?

Maybe contact these guys http://www.users.on.net/~sapug/ they are into CNC, I'm mainly mechanical.

Tony

Its easy to make a mistake......you were not the first and you won't be the last either!!

Mach 3 is a good program, but a bit too expensive for DIYers like myself, but luckily there are so many Freeware softwares around for CNC and the like, that should never be a problem.....

Using an older computer with a Parallel port is a good idea, but I would still recommend buying a plug in printer port card as if you burn the built in port, you will need to replace the motherboard!!! A car can be replaced.

Laptops can be even more of a problem as the interface is often only around 3 volts instead of 5. And don't forget its only a TTL output, that means source only 2.6ma and sink 24ma.....not a lot to work with.....!!

I have a blog on Yahoo that concerns itself with safe and correct usage of the printer port, if you want to have a look or join goto:-

Or search under yahoo for the name:- DIY_CNC_Interfacing

The various good freewares around don't mind an older PC and there are versions for DOS and Linux.....where the older hardware still runs many times faster than needed.....a Pentium type with a speed above 500Mhz should be just great.....

If you, or anyone else for that matter, need more infos just ask, its no trouble to help.....

The CNC link you posted means they are a bit too far away for me and their online presence is about zero (which is the only way I could get to a meeting!!), only interesting for people who live in SA (near to them) I am afraid.....

We have a lot of people in the club, whose knowledge is far superior to mine (not hard) and I'm happy to ask if they are interested in communicating by email.

Tony

OH !! South Australia (where I have visited several times, nice area, got about 70 relatives down under mostly in that area.....!). I thought you meant South Africa, sorry!!!

I agree with Tony for light loads picaxe sell a pic with driver and free programming software so you can easily connect a stepper and program it. Add a few switches and you can change speed, direction, duration etc so you don`t really need a computer attatched all the time. Course it does depend on the application which hasn`t been stated. Look at the Rev Ed site for various board options and instructions on interfacing. Avoids blowing your parallel port if you are unsure.

I don't know what software you are going to use, my I recommend NOT a Windows software as WinDoze sticks its sticky little fingers all over the place......only expensive software will really work I find.

If you are a cheap person (like me!) then use an older PC with a plugin Par. Port or laptop with a PCMCIA card, as if you burn something (there are some REALLY badly designed interface ports that take FAR too much current from the printer port), you can replace the card, instead of the mainboard.

NEVER USE A MAINBOARD PRINTER PORT IN THIS WAY, ITS TOO DANGEROUS FOR THE MAINBOARD!!

There is plenty of free software under DOS or Linux or write your own....an older PC is fast enough to drive up to 10 or more steppers.....and far far cheaper, sometimes even free.....

I have a yahoo blog on correct interfacing of steppers to the Printer Port if you want, I can give you the link (offline), so just ask if you wish, or anyone else for that matter......

This may work for your application and with the os in the netbook:

http://www.cablestogo.com/product.asp?cat_id=1537&sku=16899

Thanks for all the answers, this forum is seriously overflowing with knowledge.

At this point I dont want to use a PIC because I have never used one before, and because it sounds more expensive.

What Im trying to do is: develop a (VB) program that I can use to test the steppers (taken from old printers) and later on to simply control a small, home-made CNC. I would like to create my own software for machining parts, but in order to do that, the interfacing needs to be simple.

My netbook doesnt have PCMCIA, but if it did, I couldnt afford that adapter right now, as i want to make this project with as little money as possible.

So, I guess at this point my only option is to use my own computer (not the netbook) parallel port, with adecuate diodes in the driver to prevent blowing the motherboard.

Again, thanks for all the input,

Testing is easy enough but with a 3 axis machine you will need to drive at least 12 outputs and you may find that a CNC user group could recommend a better board option dedicated to the task. www.cnczone.com may be helpful. This 18 pin board is £6 plus another £6 for the 18 x chip with the serial lead for programming. You may need a usb to serial if so add £9.39 plus p.p. Software is free.

With Picaxe you can use VB6 to interface with the chip read and write if you have mscomm. I think it comes with VB6 Pro. But other basics can also be used. I have used it to plot graphs from analogue sensors on the pic.

Good luck

If you must stick with USB its going to be difficult, but if you are writing your own code as you said, then you should be able to do it with a PIC. It does have a bit of a learning curve, but if this is what you need and you want to write your own code, I would look there.

If you have some money to spend I can suggest other options although I don't know how well they work. Anyhow here is the part where I give you some links to look at.

This site sells a USB cnc controller

This site had directions to build your own USB to parallel converter, and I think but am not sure that this one could work.

This site is a general site for building a cnc stepper controller but I thought I would add it.

Good luck with your project. Once you get it up and running, perhaps you will do a write up and post it to the workbench creations blog.

In my experience I also had problem to match parallel port device by USB adapter. Once I also wanted to have 2 parallel ports in desktop PC. I installed PCI card with additional parallel port, play with settings long but didn't work either. (I wanted to probram FPGA by ISE app.)

So, I thing that if your software access parallel port directly then you have problem. If you software use operating system functions mediating access to parallel port then there if chance that your USB adapter will work.

In my (limited) experience, its a question of getting a good card with good software/drivers. Some of the cheaper cards have bad drivers......some of them have good drivers. You are not the first to have such problems.

Certain Windows versions make it difficult to install such cards, Vista for example is very difficult I am told (no personal experience as I use WinXP Pro only on all PCs and Laptops except one which has Win98SE). I have no idea if Win 7 is better/worse than Vista or not....

On older PCs where DOS is used for CNC work, they seem to work just fine.

Linux is also good at finding and using plugin hardware.....

Plug and play PCI cards are usually less of a problem I have found under Windows....but not all modern PCs can take the older (wider) PCI standard I believe...

Just my 2 Cents, I hope that it helps....

There are stepper driver chips using two inputs (step & direction).

Even so, getting access to your registers are made difficult on Windoz. (but it can be done)

The speed factor is another problem.

To do an arc or a skew line you would have to time the pulses to obtain the correct ratio of pulses and blanks.

What I like to do is to use the electronics of a pen plotter - motion can then be programed in HPGL.

I had to give you a GA, for defining one of the problems that I was of the opinion that I could not address properly and for giving a simple fix to use HPGL!!!

There may not be one available. And I'm no expert on USB communications... but it seems to me that emulation of a parallel port via USB should be, theoretically, possible, if a hardware adapter is part of the equation. In other words, a conversion of USB commands to real parallel hardware (and vice versa) would have to be made some where along the way.

I found this product as well, which should do the job although if you want to write your own software you are going to need to wait for them to release the SDK. Currently it looks like it only works with Mach3 but they say they are going to make an SDK.

http://www.warp9td.com/