Intro:

    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 120USD).

Components you'll need:

    -A bare VFD unit capable of LCD emulation. Some different sizes, Farnell codes and prices:

        2x16    882940    £34.94
        2x20    882951    £35.54    *the one I used
        4x20    882963    £58.42
        2x40    882987    £53.64

    -A 25 pin parallel plug (1354966).
    -Some ribbon cable (148317 per metre).
    -Some black tape.
    -A male Molex connector.

Tools used:

    -A soldering 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.

What you 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 here (though the character set shown on this datasheet is incorrect).

Connecting her up:

    Wiring this 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,

    *Pin 3 does actually have a function but we don't need it here.
     **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 article,

Testing...

    After plugging 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 both LCD Center2.0 and LCDSmartie (now capable of displaying game stats!) work well. Some pics of her running...

LCDCenter,

LCDSmartie,

Conclusions:

    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 colour? Matrix 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 from Farnell as well as their own).