Erik Reikes wrote:
>
> At 09:16 PM 10/25/99 -0400, you wrote:
> >
> >That sounds good, but what about dirt?  Is that an issue here?  If it
> >is, the only reliable way I can think of doing this is to have two
> >temperature sensors and a hygrometer:
> >
> >   1 temperature sensor monitoring ambient temperature
> >   1 hygrometer measuring humidity
> >   1 temperature sensor monitoring the glass surface temperature
> >
> >If the temperature of the glass gets close to the dew point, then
> >kick the heater/fan on.
> >
>
> I know there must be some reason you can't do this or somebody would have
> said it already...
>
> Why not just leave the fan/heater on all the time?
>
> Or at worst cycle it to lengthen the life...
>
> -Erik Reikes

Noise, heat conservation, battery life, and the fact that heat
generation (in this case) comes in big bursts, that cannot be really
predicted - My 3rd choice here is to run a 12v fan at 9V or so, which
works, and gives a nice slow fan speed that overdoes it (but you can see
through the glass/plastic window when you want to!)  Also could just
have a user-operated switch, even cheaper.  Having it just handle the
problem, and then stop, would be a really good solution, though.

  Mark