Parallel port control with USB->Parallel converter

[Soren]

Hi,

I want to control some motors using the parallel port.. however, my
laptop does not have any parallel ports (very few do). What I do have
is a USB->Parallel converter... I thought about using PyParallel, but
the USB->Parallel converter doesn't actually map to the LPT port ..
and PyParallel only looks for LPT ports?

Has anyone tried doing this? What are my options for controlling
parallel connections on a laptop with no parallel port?

I also thought about controlling the USB natively.. but since I dont
have any instructions on how to do this with my Velleman USB->Parallel
port converter... i guess I would be totally blind.

Any help would be appreciated!

Soren

 

[Diez B. Roggisch]

Hi,

I want to control some motors using the parallel port.. however, my
laptop does not have any parallel ports (very few do). What I do have
is a USB->Parallel converter... I thought about using PyParallel, but
the USB->Parallel converter doesn't actually map to the LPT port ..
and PyParallel only looks for LPT ports?

Has anyone tried doing this? What are my options for controlling
parallel connections on a laptop with no parallel port?

I also thought about controlling the USB natively.. but since I dont
have any instructions on how to do this with my Velleman USB->Parallel
port converter... i guess I would be totally blind.

You could try and see how far you get with pyusb, the wrapping for libusb.
However, any decent usb2<somewhat>-adapter should register itself as device
of the mapped kind. For example, usb2serial-converters appear as
COMxorts.

So I *guess* you are having driver-problems if the converter doesn't show up
as parallel port.

Apart from that, you might consider using products like atmel's USB-Key or
similar to attach a microcontroller to the USB-port that then will use it's
own ports to control the motors.


Diez

 

[Soren]

Hey Diez, thanks for your answer!

You could try and see how far you get with pyusb, the wrapping for libusb.
However, any decent usb2<somewhat>-adapter should register itself as device
of the mapped kind. For example, usb2serial-converters appear as
COMxorts.

That was my thought too, and that's why I bought one (actually I
bought two), but it turns out that people only use these to interface
with old printers.. and so the converter is listed as a USB printer
port, and does not directly map itself to the LPT port.. Of course,
there must be some way of controlling the USB2PAR the way I want, but
without something like PyParallel or an API for this converter.. im
pretty much in the blind.. :/

Apart from that, you might consider using products like atmel's USB-Key or
similar to attach a microcontroller to the USB-port that then will use it's
own ports to control the motors.

I thought about it.. this would be my last option however... mostly
because it would take too much time to get acquainted with it. I need
the thing running before the beginning of March among other
things.. I do have a LabJack USB DAQ, which is really nice... but
unfortunately it's too slow for running 5+ motors in parallel by
sending pulses. I also thought about extending the labjack with faster
pulse generators that could be triggered from the labjack.

Using the parallel port or USB2PARALLEL on the pc would just be so
much simpler, cheaper and faster... So if anyone know how to hack an
USB-Parallel converter to let me send bytes to it.. I'm all ears!!

Soren

 

[c d saunter]

Soren,
I don't know about the USB parallel port converters but there are
variousways you can add USB connectivity yourself.

A simple way are the USB devices from FTDI
(http://www.ftdichip.com/FTProducts.htm)

Either the FT232R or the FT245R. These are both single chip solutions
that provide a USB interface on one side and an 8 bit bi-directional fifo
on other. The 232 is mapped as a serial port at the system level, whilst
the 245 is higher bandwidth and accessed through an API (use ctypes etc.)
Windows, Linux & Mac OS X are supported.

FTDI provide evaluation modules (tiny, USB powered) that you can be up and
running with in no time:

http://www.ftdichip.com/Products/EvaluationKits/FT245RModules.htm

Good luck!

regards
cds

Soren ([email protected]) wrote:
: Hi,

: I want to control some motors using the parallel port.. however, my
: laptop does not have any parallel ports (very few do). What I do have
: is a USB->Parallel converter... I thought about using PyParallel, but
: the USB->Parallel converter doesn't actually map to the LPT port ..
: and PyParallel only looks for LPT ports?

: Has anyone tried doing this? What are my options for controlling
: parallel connections on a laptop with no parallel port?

: I also thought about controlling the USB natively.. but since I dont
: have any instructions on how to do this with my Velleman USB->Parallel
: port converter... i guess I would be totally blind.

: Any help would be appreciated!

: Soren

 

[c d saunter]

Doh!

It's been a while since I used these.

I was slightly wrong; actually both the 232 and 245 devices can be
accessed either via a serial port interface (COMx on windows, /dev/??? on
linux etc.) or via a direct API.

The 245 provides a parallel FIFO and the 232 a serial data link, so you'd
want the 245.

regards
cds

c d saunter ([email protected]) wrote:
: Soren,
: I don't know about the USB parallel port converters but there are
: variousways you can add USB connectivity yourself.

: A simple way are the USB devices from FTDI
: (http://www.ftdichip.com/FTProducts.htm)

: Either the FT232R or the FT245R. These are both single chip solutions
: that provide a USB interface on one side and an 8 bit bi-directional fifo
: on other. The 232 is mapped as a serial port at the system level, whilst
: the 245 is higher bandwidth and accessed through an API (use ctypes etc.)
: Windows, Linux & Mac OS X are supported.

: FTDI provide evaluation modules (tiny, USB powered) that you can be up and
: running with in no time:

: http://www.ftdichip.com/Products/EvaluationKits/FT245RModules.htm

: Good luck!

: regards
: cds

: Soren ([email protected]) wrote:
: : Hi,

: : I want to control some motors using the parallel port.. however, my
: : laptop does not have any parallel ports (very few do). What I do have
: : is a USB->Parallel converter... I thought about using PyParallel, but
: : the USB->Parallel converter doesn't actually map to the LPT port ..
: : and PyParallel only looks for LPT ports?

: : Has anyone tried doing this? What are my options for controlling
: : parallel connections on a laptop with no parallel port?

: : I also thought about controlling the USB natively.. but since I dont
: : have any instructions on how to do this with my Velleman USB->Parallel
: : port converter... i guess I would be totally blind.

: : Any help would be appreciated!

: : Soren