I do a lot of work with Home Automation on my Mac using a program called XTension. One of my problems is getting notifications of things. I've always wanted to have displays all over the house but the price of any such thing has always been way too high to play with. I noticed some serially controlled VFD displays at BG Micro for less than $25 USD and just had to give them a try.

This is what arrived:

A VFD is a bright display, like the one probably on your VCR, not like an LCD or LED display. They have the same annoying parallel interface as most LCD's though, which makes them hard to control from a Mac with only serial ports unless you pop for more expensive hardware and do a lot of custom programming. This being a serial device was easy to program for! It also has an inverter to supply the high voltage to the display onboard so you only need one 5v regulated supply to run it!

It only has one data line that you need to worry about, the transmit line from the serial port, so only 3 connections to make including power! The local Radio Shack didn't carry a case the proper size so for the time being this one is living taped inside a plastic box. It's important not to run the thing without a case! There is an inverter in there creating very high voltage, probably on the order of 200v maybe higher, to drive the display elements. That could be very painful or dangerous. You have been warned!

First I needed a 5v regulated power supply. You could probably run it off of a wall wart, but it must be DC and must be regulated. According to the docs on this specific display its over voltage tolerance is non-existent. I have several external drive cases that I'm no longer using with good power supplies, so I took the one with the largest capacity supply and added some screw terminals in the front of it to supply the 5v and 12v for the display. The 5v current that this supply gives would power many displays. I used to use an unregulated 12v transformer to run the rest of my home automation system but I've now switched it to the regulated supply too. It's working great. It looks like this:

I attached it to the Mac and wrote some software to control it via applescript and this is what I've got now hanging from the shelf above my workstation. Here it is updating me as to the temperature in my lab and outside on the deck. It does this every 5 minutes or so for 2 minutes and then blanks out. If you leave a static message on the screen for long periods of time you will more rapidly wear the thing out. These are removed from "medical equipment" and while the useful life can be anywhere between 40k and 100k hours I dont want to wear it out too soon. It is also powered down whenever nobody is actually in the lab to see it. (More magic via an X10 universal module, XTension and a motion detector in my office!)

Combining this display with my web server and X2Web setup was not difficult. You can send me a message from this page. The display is only 2x20 characters, so it will have to be a short message:

BACK ONLINE! The VFD Display is connected again, and you can send me a note through it again!