In a message dated 97-02-20 23:57:58 EST, you write:

<<
 Thanks for the information regarding the current consumption.  Also,
 thanks for the tip regarding the left over I/O lines -- I didn't know
 that.

 It appears that the project will use somehting like 6mA.  I'm
 assumming 2mA for PIC chip, and 1mA each for the ADC0831, DS1305
 clock, and DS1620 temperature sensor.  The eeprom I believe will draw
 about .5mA.  I threw in an addition .5mA for "overhead."

 According to a table I have, a heavy duty D battery has a life of 702
 hours with a load of 8mA.  So, if I use 4 D batteries to give me the
 5vdc, the circuit should run for about a month.


 Richard Rosenheim
 rrose@accessnv.com

  >>
Richard,
You are welcome.  D batteries are pretty robust.  If youve got the room they
are a good choice.  What EEprom are you using?  I make a battery operated
device that is worn on the wrist of Astronauts!  I use the 24AA64 serial
eeprom in it.  This is one of the slickest serial EEproms I have seen.  It
will operate down to 1.8volts.  No external programming voltage, and you can
gang 8 of them together for a total of 64K bytes.  The draw in the micro amps
for reading and require only 3ma for write. (Writing only takes a few milli
seconds so the curent is no big deal)  I use 24 of them in the wrist worn
monitor.  I power them down when not in use and I use an I/O pin to power
them up (most I/O pins will source 25ma.  Microchip has an apnote that
describes using a I/O bit to power up and down Serial EEproms)
Also If you need a LED. Flash it at half second intervals with an on period
of 10 milliseconds or so.  Your instantaneous current will be 10 ma or so but
average that out over time....  You can run LED a very long time on batteries
this way.

Good luck
Dave Duley
V.P. DreiTek Inc.