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Simple solar garage door controller?

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Posted by nicksanspam on December 16, 2004, 3:21 pm
I'm thinking again about covering the outside of a south-facing garage door
frame with a layer of polyethylene or polycarbonate (with better views and
longevity) to solar heat the garage and provide lots of workshop daylight.
Would anyone (Duane?) like to invent a simple controller to open and close
the door automatically, given the electric opener? I might buy one.

It would be nice to invent an inexpensive circuit that simulates pushing
the button, without getting into the detailed electrical design of each
different brand of opener. We might deliver a 1 second pulse to Grainger's
$.76 5ZC15 120 V 0.9 VA (16K ohm) relay when their $3.65 2E158 SPDT line
voltage thermostat in a glazed box closes on temperature rise, and another
pulse when it opens at the end of the day, with a 400 V 100 uF electrolytic
cap for a differentiator, but there's likely a simpler electronic solution
with a small power supply and PIC and reed relay.

And since pushing the button both opens and closes the door, something
should sense whether the door is open or closed and keep it in phase with
the sun. It would also be nice to be able to override the control to open
the door at night sometimes and inhibit door opening when nobody's home.


Posted by nicksanspam on December 17, 2004, 8:51 pm

This box could also turn on an exhaust fan to cool the garage if it got
too hot and turn on the fan at night when outdoor air is cooler than garage
air to cool it in summertime and turn on the fan during the day when
outdoor air is warmer than garage air to warm the garage in wintertime,
if the dew point is higher than any indoor garage surface temp, to avoid

It looks like Onset Computer's $75 Tattletale TFX-11v2 could do the job,
with their $75 development kit and a couple of $2 12-bit Sensiron SHT75
RH/temp sensors, but maybe that's overkill...


Posted by Sylvan Butler on December 18, 2004, 4:12 am
 On 17 Dec 2004 15:51:07 -0500, nicksanspam@ece.villanova.edu

Way.  For one-of the cost doesn't matter as much, but $50 to get
started seems incredibly excessive.  Consider the "jellybean"
microcontroller approach...

1) Identify the sensors.  Those are likely to be the same or similar
   with any microcontroller.  (Tho' you could use analog sensors if
   you chose a microcontroller with A2D inputs.)

2) Identify the required controls (eg relay or ???).  Interfacing those
   is going to be about the same no matter what microcontroller.

3) Now choose a microcontroller.  Maybe choose development langauge or
   tools or kit or whatever first, and use the requisite microcontroller.

I chose PIC.  A $ Microchip PIC (12f683) requires about $ in
development kit, (but spending $0-$0 on a programmer like the wisp628
at http://www.voti.nl ) gives added flexibility) has 6 I/O lines,
including 4 A2D inputs, and probably has plenty of code space (FLASH),
data storage (EEPROM) and RAM to do the job.  A $2 chip (16f877a) bumps
that up to 32 I/O lines and oodles of FLASH, EEPROM and RAM plus a whole
bunch of other peripherals built in.  For ease of use I'd recommend the
16f877 or no smaller than the 16f88 (all the peripherals but only 16 I/O
lines for about $) since those can be self-programmed in-circuit, via a
serial port, after loading a bootloader into the chip.  IIRC Randy at
Glitchbuster.com will preprogram them with a bootloader for a little bit
more money, or maybe that was at sparkfun.com .  Program it in assembly
for free, there are a few free C compilers that might work for you,
PIC-FORTH is free (http://www.rfc1149.net ), a pascal like language
compiler is free (jal.sf.net), or you can buy better C compilers or a
good BASIC (ick) compiler (http://xcprod.com/titan/XCSB/ ).

I'm sure Atmel has similar products and capabilities in their AVR line,
and they have been doing very attractive pricing (trying to curry market
favor?).  Atmel has the advantage of a more normal architecture making
compiler support much easier (hence more available).  I chose to start
with PIC, so I can't speak much more to AVR.

PIC seems way more popular, perhaps a wider product line, perhaps a more
profitable company, perhaps a better committment to providing "obsolete"
parts so reproducing the projects of others is easier, and the company
has been supporting these chips a lot longer.

http://dontronics.com  (in AU) handles both and has some good info online.

http://www.piclist.com  has a lot of info, but good luck finding it...
http://www.voti.nl  has a better intro.

http://www.avrfreaks.net  was a rather nice site last I was there.

Wanted:  Omnibook 800 & accessories, cheap, working or not
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Posted by nicksanspam on December 18, 2004, 2:49 pm

Great :-) Let me know when you've finished this controller, so I can buy one.


Posted by Sylvan Butler on December 18, 2004, 4:46 pm
 On 18 Dec 2004 09:49:48 -0500, nicksanspam@ece.villanova.edu

I'll add it to my ToDo list...  Checking...  About 2007 good for you?


Wanted:  Omnibook 800 & accessories, cheap, working or not
sdbuse1 on mailhost bigfoot.com

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