Problem: Crawl space moisture and mold, I have to replace the floor and
joists on part of my house.

I have some PLC's with analog I/O and temperature (both RTD and
Thermocouple) input cards. I know this is overkill but it's a hobby project
that I hope will be beneficial.

To solve my crawl space moisture and mold problem I plan to install a crawl
space moisture barrier, a sump pump or two, and a dehumidifier. Like I said
I have some PLC's, the Allen Bradley 1771 chassis and cards are pretty
economical on eBay and I bought a couple of them for playing with and
learning more about.

So, for a massively overkill hobby project, I'm thinking about using an
Allen Bradley PLC 5/30 or 5/40 to monitor my sump pump operation, if the
float switch is on too long it will alert me that the sump pump may not be
working. I can also see how many times the sump pump kicks on and the total
time it has ran. Also I can use a relative humidity sensor to control the
crawl space dehumidifier, it seems the RH sensor on my house dehumidifier is
crap, once it gets close it cycle on and off every couple of minutes.

Also, while the floor is torn out, I thought I could run some wires to
measure temperature of different areas of the house and control room heaters
to the desired setpoints. Again I can monitor the ON time of the heaters
and check electricity usage. Maybe I can even have the heaters warm the
bedroom a little before I have to get up to go to work! :-)

Anyway I figure I might as well use this controller for something sort of
useful and fun to play with at the same time.

RogerN