Feature Request: Parallel Port

[Steven]

I recently bought a simple kit with 8 relays that are controlled by the parallel (printer) port. I think it would be a neat idea to use this to control things like my FM transmitter, low-power audio amp, possibly even some indicator lights.

How about letting LOR control the parallel port just like an 8-channel digital IO device? After all, LOR still has support for Dasher, which you can't buy anymore, and BSOFT, for which I can't find any information, so why not the parallel port, which you can find on any old computer?

Or is there some way to do it now that I don't know about?

Who else would find this useful?

[Vic Fortenbach]

I presently use the Dasher and LOR to control my 3D wire frame deer motors (through an SSR). The Dasher chips are still sometimes available through LOR or Dave Homes at www.chaselights.com. While the Dasher output is not dimmable, it's perfect for controlling motors.

[rwertz]

I started out with a couple parallel port boards (before I new about LOR et al). It would be great to be able to dust off my boards and use them.

I'm not sure how much of a PITA it would be for LOR to support. I know direct control of the parallel port keeps getting more difficult with each release of windows. Starting in NT / XP you had to get past the Hardware Abstraction Layer. I used a third party driver.

[Steven]

rwertz wrote:

I'm not sure how much of a PITA it would be for LOR to support. I know direct control of the parallel port keeps getting more difficult with each release of windows.

But here's an easy hack: In your parallel port interface board, wire pins 11 (Busy) and 12 (Paper out) to signal ground. Then, just open LPT1 and write a byte to it. After installing a small wire jumper on my relay board, I can control it by simply running a command like:

C:> COPY STATE5.TXT LPT1

In this case, the file "STATE5.TXT" has a single byte that contains the bits to set the relays to a certain state.

It would be just as easy to put that into LOR as it is to control X10 from the serial port.

[Guest wbottomley]

Couldn't you run that as a batch command?

[Steven]

Mountainwxman wrote:

Couldn't you run that as a batch command?

Yes, that's what I'm doing now. But it would be nice to be able to toggle these relays in the middle of a sequence.

[ErnieHorning]

One of the first outputs that we added to Vixen at DIYC, was a parallel port driver. One of the plug-in’s even allows you to control up to 12 outputs.

There’s also a plug-in to control a serial to parallel shift register IC (74HC595) and have the potential for over 24,000 outputs.

After several people ran some pretty fantastic shows that first year, we found that not all parallel ports were created equal. The parallel port was originally created just to output to a printer. There was never a spec written for it so as long as a printer worked, it was good enough. The voltages vary, the drive capability varies and the speed that it can run at is all over the map. Even for short distances.

Most of us have abandoned the parallel port in favor of the serial port instead. The parallel port is obsolete and doesn’t come on new computers. Some don’t even have an RS232 serial port but USB to RS232 dongles are prevalent and still work great.

I don’t see most LOR users having a need for any kind of parallel port capability. The majority aren’t the DIY type of user.

[rwertz]

ErnieHorning wrote:

One of the first outputs that we added to Vixen at DIYC, was a parallel port driver. One of the plug-in’s even allows you to control up to 12 outputs.

There’s also a plug-in to control a serial to parallel shift register IC (74HC595) and have the potential for over 24,000 outputs.

Yeah, I had 12 channels for my first year

We used the 595 chip to create a multiplexer scheme at work to switch between thousands of units under test. When the parallel port started getting locked down we switched to a digital I/O card. But the circuitry is still in continuous use today.