Issue
93 April 1998
Picaro:
A Stamp-like Interpreted Controller
by
Tom Napier
For
years, Tom’s been itching to control the instruction
sets of processors. Using a PIC, some memory, and
an interpreter, he bypasses the processor hurdle
and writes his own language. He shows you how to
do it, too.
This
type of intelligent building software was first used,
I believe, in certain HVAC controllers as far back as
1987. Used mostly in the lodging industry, these types
of controllers are designed to squeeze every ounce of
energy savings while providing adequate comfort. In
many cases, the occupants don’t even realize that
energy management is taking place.
For
this particular application, the software is divided
into two major components. The first component, the
Occupancy Detection Unit (ODU), must recognize not only
when the area is actively occupied and when it is not
occupied, but also when the area is occupied by inactive
occupants, who may be resting or sleeping.
The
other component is a Pattern Learning Unit (PLU) that
records the occupancy history for the area and attempts
to predict the next arrival.
