Re: [LCtalk] i/o with resistance

[Fokko van Duin]

At 12:00 -0400 05-05-2006, ted nordlander wrote:
> I'd like to have a photo resistor regulate the transparency of the top 
> layer [which will be channels 1-8 full intensity], under which a simple 
> wave pattern will be play (channels 1-8) on the layer below.  So when 
> it's sunny outside all the lights will be on (top layer full 
> intensity[transparency 0%]) and when it's dark one sees the wave 
> pattern below(top layer 100% transparency).

This can only be done with some custom Forth programming in the LCX, 
or use e.g. MAX to translate the analog input signal to a layer's 
transparency.



> the first question is wiring the I/O inputs correctly.  Just to verify 
> would I attach a diode and a 47k resistor to the 6v and attach the 
> photo-resistor between the the the diode and and input?  Or would it be 
> a more elaborate circuit.

If you are using a standard LDR, just connect one side to the +6V, 
the other side to the analog input, and also connect a 4700 ohm 
resistor between the input and 0V.



> I figure I'll test it first using a potentiometer between the 6V and 
> 0V first with the wiper on the input. I think this is right?

Correct.



> next: what would the syntax of controlling the transparency be?  It 
> would be great if it didn't have to jump between cuelists, but could 
> be more analogue.

There is no action to do that, but it can be done with a few lines of 
Forth code. For more info see this thread: 
http://www.lanbox.com/support/Talk-Archive/msg-01192.html

--
Fokko van Duin,
CDS advanced technology bv,
http://www.lanbox.com/