piclist-bounces@mit.edu wrote:
> Interesting,
> The thing that imediatly jumps out at me is the cyclic rate of the
> relays. At a 8 second cycle rate, that works out to be ~10,000 cycles
> a day - more at four seconds. I wouldn't expect a mechanical relay to
> have a very long lifespan at that rate. 

Yes, the relay life could be an issue. A long time ago, i constructed
a powerhead controller for my reef tank using optically coupled triacs. 
The circuit didn't have a PIC; I used a CMOS counter to count AC line 
cycles through an H11AA. There are a lot of examples on the web on using
optically coupled triacs.

For night/day sensing, wasn't there a piclister who did just such a
project? 

In any case, you can use MPLAB and MPSIM to learn about PICs and 
assembly without having to have a working circuit. And the 'blinking LED'
project still has lasting value if you have limited experience with 
building actual hardware. The piclist site has a lot of useful info and
tutorials. Microchip has some code templates.

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist