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VFD display hacking

From: Doug Sutherland <>
Date: Thu, 6 Apr 2000 14:54:00 -0700

Yes!  Well, it was a hell of a lot of tedious work involving some 
92 solder joints in all. But I was able to remove the display 
from one of the matrix-orbital vacuum flourescent display modules
and make extension cables betwen the driver module and the actual
glass display. Up until now I had the whole module embedded in my
sleeve which was too bulky, heavy, and uncomfortable. 

I made a custom cable that goes from a 10-pin serial port header
on the mighty mite carrier board to the VFD driver module. The 
driver module is now connected to the display with about three 
feet of ribbon cable, so all I need in the sleeve is the glass 
display, the driver module resides in the jacket body lining. I 
also have custom ribbon cables running from the display driver 
to a small 3x2 membrane keypad on my sleeve and six tiny LEDs 
under the display on my sleeve (the display driver hardware 
also has a keypad interface and six general purpose outputs 
that I am using to switch LEDs on and off).

It was a nerve-wracking experience and soldering onto the pcb
was not fun, but it was definitely worth it. I find that using
a 4x20 display is very useful in a wearable design for things
that don't require a lot of user input. For example I can 
display GPS data, sensor readings, system state, etc. Also, 
having it on my sleeve is very convenient, I can actually use
it safely while driving, including reading info and pressing 
buttons on my sleeve cuff keypad. Another thing that I like 
a lot is the readability of the VFD displays, they are very 
bright. I am going to add a polarized filter which will make
this thing readable in direct sunlight. 

I will try to get some pictures up soon so you can see what 
it looks like. If you are interested in trying this module
out, you can find it here:

http://www.matrix-orbital.com/vfd-home.htm
http://www.emjembedded.com/products/alnumdisplays/vfd.html 

I have written a set of Java classes that make a nice API
to the matrix-orbital displays. This allows me to send 
simple commands like clearDisplay() and positionCursor(x,y)
and drawVerticalGraph(x,y,z) etc rather than sending hex
escape codes. Soon I will make these classes available if 
anyone wants to try them out.

  -- Doug

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