I'm sure by
now you've seen or heard about parallel LCD's:
a cheaper alternative to serial LCD's with various
advantages and disadvantages over their serial
brothers. I discussed these briefly in this
review. Along the same lines it is possible
to buy a bare bones VFD unit and wire it up
to your parallel port... and I'm going to show
you how. If you're not very good with a soldering
iron, want a simple life or want to use features
like keypads and GPO's then Matrix
Orbital sell serial VFD's here
(the VFD in this article costs around £45 to
set up; a Matrix
Orbital display of similar size costs around
-A bare VFD
unit capable of LCD emulation. Some different
codes and prices:
*the one I used
-A 25 pin
parallel plug (1354966).
-Some ribbon cable (148317
-Some black tape.
-A male Molex connector.
iron (preferable with a thin tip).
-Some pliers or wire strippers.
As you can
see the VFD I used is LCD compatible - meaning
it is controlled in almost the same way and,
as you'll see, is wired almost identically to
a parallel LCD (a quote from Farnell - '(these)
VF displays are designed to be electrically
and mechanically inter-changeable with LCD modules').
If you're interested in how
a VFD works have a look here.
get for your money:
A closer look at the unit:
Made by Noritake
this is a very good quality display - as in
most parallel units the character set is inbuilt
and this VFD has an especially large one with
many strange and funky characters in it (degree
symbols etc.). This VFD's datasheet is available
(though the character set shown on this datasheet
unit up involves connecting 10 of the pins from
the VFD unit (shown on the right-hand side of
the picture taken of the back of the VFD above)
to 10 pins on the parallel plug and 2 pins to
the 5V and earth lines on a Molex connector
(from your computer's power supply). A close-up
of the pin outs on the VFD,
Connect these up as follow,
out on VFD
*Pin 3 does
actually have a function but we don't need it
**Pin 5 is earthed
as we will only be writing to the VFD.
Those of you
with a good knowledge of parallel LCD's will
have spotted the only main difference between
these pin connections and those for an un-backlit
parallel LCD: pin 3. On LCD's pin 3 is
normally used to adjust the LCD's contrast;
on this VFD pin 3 has a special (and quite boring)
function. I ignored it!
Some pictures of the finished
the unit into a free parallel port and the power
connector into a spare Molex connector on your
PSU you should have a VFD that functions just
like a parallel LCD. I was quite worried when
I first plugged mine in and powered it up. Unlike
an LCD I got no test signal; this appears to
be normal for a VFD.
I use Windows XP so the available
parallel LCD software is a little limited, but
Center2.0 and LCDSmartie
(now capable of displaying game stats!) work
well. Some pics of her running...
I'm very impressed
indeed by VFD's - they are much easier to read
than LCD's and in my opinion look better (even
the bare unit has a more techie feel to it,
difficult to describe). At £40 this unit from
Farnell is difficult to resist! Fancy a different
Orbital have recently started selling coloured
VFD filters to fit 2x20 and 4x20 VFD's; they
will fit the similar sized Farnell VFD's too
(!) - have a look here
(I'm also told Matrix
Orbital's mounting kits will fit these VFD's
as well as their own).