Re: Stupid home non-automation product

["Jeff Volp" <JeffVolp@xxxxxxx>]

"Marc_F_Hult" <MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:gfptu2hlpvs1ebti25dafoepao715rvndt@xxxxxxxxxx
> On Wed, 07 Mar 2007 15:34:13 GMT, "Jeff Volp" <JeffVolp@xxxxxxx> wrote in
> message  <VXAHh.42698$as2.22509@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>:
>
>>While what you say about archiving data is true for the Ocelot, one can do
>>complex decision making.  For example, I run our garage exhaust fan in the
>>early morning hours when the previous day was hot, and only while there is
>>a  significant delta T between the garage temperature and outside air.
>>This  simple approach keeps the garage almost 10 degrees cooler in the
>>summer.  Temperature sensors are cheap thermistors read through a SECU16.
>>Some simple code linearizes the readings over the working temperature
>>ange so it can be displayed in degrees F.
>>
>>Jeff
>
> Sure. This is a relatively simple rule of the form:
>
> WHILE [Time period}
> IF [computed value] > [constant] THEN [Boolean result]
>
> One has been able to point-and-click through this sort of computed
> rule-making using windows-based CyberHouse for a decade.
>
> But there is very little "historical data" and no "statistics" involved.
>
> And the rule might not be smart enough to avoid violating the "do no harm'
> maxim.  For example, if the positive delta T is because there is a fire in
> the garage, will the system know not to literally fan the flames?

A little more complex than that because it does use the max temperature from
the prior day.  Just about every summer day here is a carbon copy of the day
before, so that works well to anticipate high for the day.  No sense burning
electricity if it isn't going to be at least in the 90's.

The fan will switch on one hour before sunrise only if the prior day was
hot, and the outside temperature is at least 8 degrees cooler than the
garage at that point. The fan shuts off if the delta T drops below 4 degrees
or the garage starts to warm up.  Again, no sense burning electricity if it
isn't helping.  While not intended to deal with a fire, I think that
condition is pretty much covered.  I suppose adding a high-temperature
lockout for redundancy wouldn't hurt.

Jeff