Hello all.

Just recently, I have been asked to try and build a computer system for
control of some stage lighting.  Having spoken to a friend of mine who is
reasonably knowledgable in the field, he thinks that the best idea would be
a PIC to interface to the PC serial port, and output to a DAC connected to
the low voltage control side of the lights.  As I understand it (being a
student and all...<g>) the analogue output of the DAC would be a variable
voltage. The way in which the existing system works is to have a main switch
block (no idea whats inside it) with a Low voltage control panel connected
to it. The panel is just a set of variable resistor sliders as far as i can
tell.
Anyway, back to the bit i'm confused about...depending on the internal setup
of the lighting controller, would a variable voltage be compatible with a
variable resistance?
If not, is there a simple way to control what is effectively a variable
resistor from a PIC? (low cost solutions would be nice, as speed and
accuracy isn't really that important, and it needs 30 channels)
Feel free to point out any errors in this, as I don't have much experience
with electronics other than A Level physics (well, I suppose I have learnt
to pick up the soldering iron by the cold end <g>)

Thanks in advance

Tom Feist

Tom<AT>bisti<DOT>globalnet<DOT>co<DOT>uk


PS. I think there are probably nice simple ways of doing it - a bulb of
varying intensity by mark-space ratio and an LDR instead of the control box,
but I really have to justify to my parents why they're buying me the
PICstart pack, and I'm not sure what to start with yet....so I'd like to use
a PIC if possible <g>