Chicken Clock

[mick the mend]

A friend has asked me if I can build a timer to control a door lock/opener to operate twice a day - open just after dawn and close just after dusk. I was going to use a simple Pic and LCD. I would like to use Flow Code but at my age I can't get my head round the logic so any guidance would be welcome. I don't mind building the lookup table for the calender timing as that part is just boring (365 open 365 close) bugger the leap year.

[sphinx]

use a photo resistor that you use for sensing light/dark then just a relay for it to open as soon set lightness is ok then when it gets dark close circuit no need for either pic or lcd

/regards

[Wizpic]

You can just buy a On-at-dusk Off-at-dawn light controller for a few dollars and use it's signal. It will have all the circuitry to prevent undesirable operation due to lightning flashes, car headlights, etc.

http://www.amazon.com/ACE-DUSK-DAWN-LIGHT-CONTROL/dp/B000UEIAEY
http://www.touchandglow.com/Dusk-To-Dawn-Light-Controls-s/4.htm

That takes all the fun out in building one and our hobby :-)

[solutions]

  Yes..and you can wave your hand over the light sensor and it's "dusk" any time of day....with a flashlight, the "sun" can rise all night. 

There may be a RTC chip or app note for a micro, arduino, or whatever, that'll get you there with a clock. 

Speaking of which, you can take the minute and seconds hands off a clock movement, use a brass hour hand, and use it as a 12 hour switch pole by drilling a hole in the clear plastic cover...mechanical contact or optical switch from there....if that's too James Bond for you, a simple wall timer running on the mains will do it as well

[oldvan]

Many PIC24F family have RTC built in, takes care of the clock issue with limited pain.

The MacGyver options add more adventure for sure.

New feature idea:  Fox detector that does NOT open the door if a fox is waiting in a dinner jacket & carrying a fork.

[Ichan]

Negative side of RTC is it need battery or capacitor backup, once it missing the timing will be messy. Imagine how to change that little backup battery and / or re-ajdusting the RTC on the top of street lighting pole. Got this kind of problematic once, with a remote sensing device which is located deep in the forest.

-ichan

[oldvan]

Ichan:  Most people I know don't raise their chickens on top of street light poles, lest all the eggs are scrambled.  

Could say phooey on RTC, go GPS like I did on my garage clock 9 years ago.  http://oldvan.com/garage/

When the stated goal is dawn and dusk, a photo-sensor seems most sensible and least expensive.  Maybe the
chickens don't want out as early on dreary days anyhow.

[mick the mend]

Ok all, this isn't a joke.
The clock chip is all very well but dawn and dusk varies by hours during the year so not a lot of use. using a light sensor has been tried without success as hens KNOW when dawn is regardless of the actual light levels which vary a lot depending on weather etc. Cockerels aparently start making a noise BEFORE dawn if they are locked in so 30 mins before dawn is needed.
What I had in mind would be to program in actual times based on the date using a lookup table

My mate would like to be able to vary the opening and closing times

Thanks for the silly comments though

[Ichan]

Haha.. you are right Oldvan, chicken will not like that. The Solar powered lighting pole is in my mind right now, can't decide it yet how to control the on/off time, it should be a cheap solution.

GPS is the best if the cost is not a problem and the location is good for receiving the satellite signal.

Mick, if you haven't then reading the thread below might be useful. Me still don't understand it.

http://www.sonsivri.com/forum/index.php?topic=32632.0

Edit: see Microchip AN1303A-Software Real-Time Clock and Calendar Using PIC16F1827, cheap enough US$1.82 a piece at digikey.

-ichan

[pickit2]

could you not adapt an egg timer?

Mick, if you haven't then reading the thread below might be useful. Me still don't understand it.

http://www.sonsivri.com/forum/index.php?topic=32632.0

Edit: see Microchip AN1303A-Software Real-Time Clock and Calendar Using PIC16F1827, cheap enough US$1.82 a piece at digikey.

-ichan

[solutions]

Ok all, this isn't a joke.
The clock chip is all very well but dawn and dusk varies by hours during the year so not a lot of use. using a light sensor has been tried without success as hens KNOW when dawn is regardless of the actual light levels which vary a lot depending on weather etc. Cockerels aparently start making a noise BEFORE dawn if they are locked in........

Therein lies your answer, grasshopper

[DarkClover]

How is it if you use a simple timer switch for common power outlet? Then there are two ways. Either you catch the
signal from the internal timer or just switch a Thyristor controlled relay or something.

Or use a photoelectric sensor like the others said and connect id with the ADC of your PIC.
This would be a good learning lesson