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.
Once
the ODU has a pretty good idea of the occupancy state,
you can put this information to good use. The PLU makes
a continuous record of the occupancy state using a simple
encoding means.
Three
bytes contain a total of 24 bits, each of which can
represent the occupied or unoccupied status for any
one hour in a day. Using this method, any one-day record
can be encoded in three bytes and an entire week’s
worth of data takes only 21 bytes. Later, I’ll
show you how this encoding method makes it easy to compare
occupancy patterns.
As
I mentioned before, in this particular implementation,
the system does not even know what the actual time is.
It simply starts recording time from powerup and notes
the passing of hour, day, and week increments. As shown
in Figure 3, a record for any given "day"
indicates clearly what the occupancy pattern was for
that day.
