"Neon John" wrote in message
...
If you can come up with an old computer with a real honest-to-God
parallel port, I can give you some software that will make the job
trivial. It uses a parallel port pin to drive the circuit I
described
earlier. It allows you to set the pulse width and the total number
of
pulses. If your fluid is fairly non-volatile, you could fire the
injector into a tall glass and weigh. If it is volatile then you'll
need some sort of seal over the glass.

Sorry, never got around to porting the software to emulated ports.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address


What programming language and operating system did you use?

I'm curious because an engineer at Unitrode asked me to create an I2C
communication interface that would run on any customer's lab computer
with a parallel port, without needing a plug-in card. The device
address used up the data bits so I had to run it in DOS to have free
access to the control bits, which Windows polls. We used QBasic to get
the INP and OUT commands that access the hardware's I/O address space.

Commands to the parallel port took about 1 uS to complete on any
computer I tried, although a compiled integer FOR loop ran at half CPU
clock speed, up to 750 MHz on the fastest PC in the lab.

-jsw