The next idea was a bit different, I had the idea of animating the words Merry Christmas . . . . .    yes you've guessed it . . . .    in lights.
First of all, I had to work out the layout for the letters.  This was quite easy as I had years before studied matrix displays for characters, these represented the letters of the alphabet on 5x7 matrix.  I followed the same principle but using part of the 20 light sets.  I used only part of the set, because the characters had a different number of bulbs used to represent them.  This also produced another problem, as I'm now using a reduced number of bulbs in each string, I don't needed all of the 240 volts coming out of the mains to illuminate them.  So I calculated the required series resistance required and built this up out of one watt resistors.

The next problem was how to switch them on and off in some sort of a sequence.  No, I didn't use a box with a motor and cams in it.  I came across an I/O card kit from Maplin Electronics that fitted into a PC and enabled me to control up to 24 I/O lines.  I was really lucky with the purchase of this card as it was being discontinued & I got the last one in the clearance sale.   YES!
I built the kit which I programmed from QBASIC running under DOS6.22 because I'm not clever enough to program it in Visual Basic running under some version of Windows. - And what's more, it doesn't crash, under DOS!

Now, the output from the I/O card doesn't drive mains voltage, so some form of interface had to be built.  Enter a Silicon Chip suggested in the instructions for the kit in the form of the ULN2083 an 8 bit line driver & some 12 volt relays.  The relays are housed in a Tupperware box as it's cheap, plastic and sealable, but just for safety sake I covered the box to protect it from any ingress of rain.

Success,  I had a piece of Christmas decoration controlled by a computer.  How's that !

History Index

Messages from
     The Grinch (2011)
No Change
     (Dec. 2010)
Trees Grow !
     (Dec. 2009)
2008 Display
     (Dec. 2008)
Planning for 2008 !
     (Early 2008)
Here we go !
     (Nov. 2007)
The Big Change !!!
The Night Before
     Light-up (Dec. 2006)
The Tungsten Tree
     (Feb - Nov. 2006)
The Second move
     (Dec. 2005)
Who put that there ?
     (Aug. 2005)
Back in business
     (Dec. 2004)
Click Click Click
     (Dec. 2003)
Rope Lights
     (Dec. 2002)
The Move
     (Dec. 2001)
More Silicon Chips
     (Dec. 2000)
The Next Few Years
     & Chips
The Bug was biting
     (1993 on)
Early Married Life
     (1981 on)
A logical development
     (Dec. 1973 ish)
In the Beginning
     (Dec. 1962)