Arduino and L293D controlled chicken coop door opener

[troseph]

I'm almost done with the brain of my chicken coop door opener. All I need is my H-bridge and to build the pulley system. I'll attach photos of what I have now.

The idea is a light sensor on the roof reaches a certain measurement, checks again in 6 minutes, then lowers the draw-bridge style door. Waits 12 hours and pulls the door back up.

What I have used:

BBB Freeduino
TI SN754410
12v motor from a car window
photoresistor
caps, resistors, etc

[Deven]

Cool project!

I see a couple potential problems. (That you may have already addressed)
- Light sensors can be easily covered by snow / etc. You may want an alternate method (after a certain time if the light sensor hasn't reached its trigger level, it will open anyway)

- You may need a RTC (real time clock) module to do any kind of real timing. The onboard timing is a little buggy at best.

Eric could explain much better then I can. Maybe him or someone else can jump in on this.

Project looks great though! Keep us updated.

EDIT:
SparkFun RTC

You may be able to build something for cheaper, or hack something together. ($5 wal-mart alarm clock maybe?)

[troseph]

(02-01-2010 04:28 PM)Deven Wrote:  Cool project!

I see a couple potential problems. (That you may have already addressed)
...
You may be able to build something for cheaper, or hack something together. ($5 wal-mart alarm clock maybe?)

Thanks! Good points. I'm thinking a walmart alarm clock I've already hacked one of those into a daylight alarm clock so it would be a "cake walk" haha

[kiyoshigawa]

http://www.allaboutjake.com/projects/watch-winder/

This recent project on make, while not a chicken coup, could have some insight for you on using an RTC chip for task scheduling, iff'n the hacked Wally World clock doesn't pan out.

[troseph]

Do you think calling
delay(43200000); //12 hours

Would work for it to just "sit around" for 12 hours? Currently my code looks like this:


#
void loop()
#
{
#
if (sensVal > darkVal){ // duh
#
delay(360000); // waits 6 minutes
#
if (sensVal > darkVal){ // checks the sensor again to make sure its really the sun not just some retard in the neighbors driveway
#
doorDown(); // lets door fall open gracefully
#
delay(43200000); // waits 12 hours.
#
doorUp(); // pulls door back up
#
}
#
}
#
}

[kiyoshigawa]

Looking into it a bit online, I found this thread which may be helpful to you as well.

http://www.arduino.cc/cgi-bin/yabb2/YaBB...1215338347

It seems that the arduino clock is only 2-4 seconds off per day, which isn't good enough for a clock, but it will likely do for 'about 12 hours later, close the door.' The real problem you run into here will be the overflow reset for millis() which occurs every ~9 hours or so. You would need to write some code that takes into account that millis() will jump from a giant number back to 0. Otherwise you can probably get away with just using the arduino 16MHz clock to keep time 'well enough.'

[troseph]

Ahh cool. I'll just set it up to delay 6 hours twice. kludgey but it w ill work I guess.

[troseph]

I think I am going to go with the arduino DateTime library http://www.arduino.cc/playground/Code/DateTime and shave the few seconds it will be off every day.

[kiyoshigawa]

That looks like it'll be close enough for the kind of accuracy you'll need. Good luck to you in getting it all put together.