How to build your own external VFD / LCD

Howto by richbastard @ 2002-04-30

If you want to show off with your case, you´d better have a funky looking LCD, or even better, a VFD mounted on your case. They´re pretty, 1337 and above all: usefull. You can display your proc temps, date, uptime, latest news on CNN/TomsHW or even get a notice when you receive new email. That´s great, but it´s not that handy when you have to watch at your case if you want to read your display... most ppl watch their monitor only. That´s why I´ve come up with... *tada!* the external LCD/VFD guide
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Connect your Display

Connect your display:

I know there are other guides how to connect your display, but since we want it TOTALLY external, we have to make a few changes: we don"t connect our display on the 5V rail of our PSU, but we connect it to a USB port. Nice, clean & handy...

**disclaimer: USB ports can only handle 500mA. Check your display and make sure it doesn"t drain more power! If it does, it could fry your USB port. I will not be held responsible for that!**

My 4*20 VFD used in this article drains 275mA, so we can connect it to a USB port.

Ok, warm up your soldering iron and connect the wires acording to the following scheme:

LCD/VFD hole number
Connect to:
display: ground
USB black wire (ground)
display: 5V
USB red wire (+5V)
useless for us
RS (uh, dunno what this is for)
Parallel pin 16
Read / write. Since we only use it for writing => gound this
Parallel pin 14
Enable strobe
Parallel pin 1
Data Bus 0
Parallel pin 2
Data Bus 1
Parallel pin 3
Data Bus 2
Parallel pin 4
Data Bus 3
Parallel pin 5
Data Bus 4
Parallel pin 6
Data Bus 5
Parallel pin 7
Data Bus 6
Parallel pin 8
Data Bus 7
Parallel pin 9
backlight: +5v (displays without backlight, like a VFD, don"t have this pin number)
USB red wire (+5V)
backlight: ground (same here)
USB black wire (ground)

master @ work ;^)


Notice the pin numbers go from 1 to 14, this is a VFD and therefore has no backlight (nr. 15-16). Thanks goes out to JMke who took this pics when I was assembling his 2*20 VFD!         


The parrallel port connector. Be sure to use some shrink tube!


Cut the end of the USB cable and strip it. You"ll notice 4 wires. One of them is the ground (normally black) and one of them is +5V (normally red). I"d be a good idea to double check this with a multimeter. Attach the +5V of the display to the red wire, and the ground of the display to the black wire. Don"t forget to use some shrink tube.

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