John Nall wrote:
> While I have some confidence in my ability as a programmer, I have no
> confidence at all in my knowledge of electronics (not that I don't
> give it my best shot, though).  So would appreciate any comments on a
> little scheme I am thinking about.  Without going into the messy
> details, it will involve a PIC which will get no power except from a
> solar panel. The voltage from the panel will go to a voltage
> regulator (probably a 7805) to power the PIC.  The idea is that the
> PIC will start its work when the sun comes up and raises the voltage
> from the panel high enough to start things.  When the sun is going
> down, voltage from the panel will continue to drop (and eventually
> cease altogether) and the PIC will go off.  It is a non-critical
> application, and so long as I get 4 or 5 hours of operation on most
> days, that will be fine.
>
> Now this seems too simple, so I figure I must be missing something.
> Does anyone see any possible problems that would make it a
> non-starter? (The project has to do with a trickle charger for my
> sailboat, which normally has no access to shore power).

The basic scheme for running the PIC sounds good enough, depending on what
the normal sunlight and maximum output voltages of the solar panel are.  If
it's normally well above 5V, then a 7805 might be OK.  It requires a lot of
headroom though and an LDO may be more appropriate.  Also make sure to
enable the brown out detection module in the PIC.


*****************************************************************
Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist