Electronic Circuits and Projects Forum

5th January 2010 05:49 PM

Sorry, I don't know a lot about circuit design. I can build almost anything if I have a schematic and a parts list, but the designing is beyond me.

Here is what I want.

Imagine a six receptacle power strip similar to one used on a computer desk or what ever.
Two of the outlets need to come on from dusk to dawn and only if the tempeture is below 25 degrees.
Two of the outlets need to come on at dusk, but turn off 4 hours later, or at dawn, whichever comes first.
The last two need to have power at all times.
The tempeture and light sensors need to be on seperate wires so they can be placed away from the power strip whereever they are needed.

Here is why I need this.

I have 30 free range chickens. They will continue to lay eggs during the winter months if they have light for 16 hours or more a day. They do fine in their coop if the temp isn't below 30 degrees but need heat if it is colder. Currently I am turning on lights and heat lamps as needed, but my work schedule somtimes interfears. and if the temp drops too much at night I need to turn on the heat lamps. some times at two in the morning, Or I just turn them on before I go to bed and waste 500 watts an hour.

any help would be great, and remember I don't know circuit design so dumb it down for me as much as possible.

Thanks.

-top

5th January 2010 07:08 PM

hi topsoil i am not sure if this is going to help you much but worth a try. i farm and breed chickens for a living mostly rare breeds, you can drop the light down to 10-12 hours without any loss of egg production, a simple low wattage light is fine one of those energy savers works great, in the winter we dont heat and the temp at the mo is about -3 outside and about 4c in the coops all are still laying. if you want to still run with the idea tho then you could simply put plug in timers in each socket of the strip this would allow you to set diff times for each. as for the temp all we do in winter is when we lock them in for the night (most of ours free range) we pack more birds in each coop and they are nice and snug.
we have been doing this on the farm 30+ years with no probs although we dont actualy incubate any eggs from dec to end of feb most our chickens still lay tho, hope this helps a little

5th January 2010 07:19 PM

This can be done probably easiest with a micro-controller but since you say you don't know alot about circuit design, you should probably go a different route.

First off, the 2 outlets that need to be on continuously don't need any modification. They will just be wired like normal outlets.

The other 4 outlets that need some kind of control can be switched on and off with a circuit like this:

SimpleIO - Application Note - Triac Series Gate Resistor

The component marked "T1" is a triac and in order to select the appropriate triac for the job, you'll need to know how much current whatever you're switching on and off will draw.

The next part of the design will be the input into the opto-coupler/triac circuit.

For the temperature controlled outlets, you can use a tempo sensor with an analog output. You'd then feed that analog output into a comparator which would in turn output to the opto-coupler/triac circuit and enable the AC outlets. Read this about temp sensors:

Temperature sensor tutorial - Using the TMP36 / LM35

For the outlets that turn on at dusk, you can use a light sensor in a similar fashion to the temp sensor. A light sensor like this:

SparkFun Electronics - LilyPad Light Sensor

will output and analog voltage based on the amount of light. You would feed the output of the light sensor into the input of a comparator, when the voltage drops below a certain level (i.e. the light level drops) it would turn on the opto-coupler/triac.

The 4hr timer or dawn portion can be handled a few different ways. Maybe someone else can chime in on that or you can just digest and make sure you understand everything so far. Hope this helps get you started.

BTW, you said you want the dusk enabled outlets to turn off after 4 hours or at dawn, whichever comes first. Out of curiosity, where do you live that dawn occurs less that 4 hours after dusk?

6th January 2010 12:00 AM

I've used these for simple process control. They can be clock triggered and have analog inputs available for temp sensors. The software is also pretty easy to use.
Programmable Logic Relays, Programmable Relays

6th January 2010 03:38 AM

One simpler options would to be to use the common dusk to dawn photo sensors they use on yard lights for the 120 volt control and a frost sensor outlet. The photo sensors are about $10 - $15 and have a simple three wire 120 volt 15 - 20 amp rating and the frost sensors are those things you plug a lamp or heater into that turn on when your house temperature drops below the preset level. The better ones are adjustable from around 35 - 50 degrees and cost about $15 the last time I bought one.
Both are common off the shelf items found at the local home supply centers.
Add a basic mechanical timer like the ones most people run vehicle block heaters or Christmas tree lights off of and you could come up with a basic dusk to dawn timed and temperature control system from that.

The timer sets the master on and off times, the photo sensor overrides the lights when not needed and the frost sensor tells the heaters when to go or not.

Its just a thought but its very basic wiring with a Little improvisation using common cheap components!

6th January 2010 04:42 AM

Thanks for all the replies.

I'm not looking to put off the shelf products like timers and thermo-cubes together to make a big messy fire hazard out in my barn. I've done that and believe me, no matter how many times you tell the chickens to stay away from all those wires, they won't listen. Besides I was never really happy with the results. The timers will shut off the lights at a certain time, but not so many hours after sunset. And I've never found a thermo-cube type device that would turn on around 25 degrees. most assume you want to keep water from freezing.

I'll look at the links VNE147 posted, but I'm betting it'll be a little beyond my skill to figure out which part to use and how to wire the different control circuits together and get it right. Anyone want to sketch out a schematic for me? It might be worth a few $$ if it works.

-top

6th January 2010 06:03 PM

Here is what I have found so far.

Thermostat. Selco - WK1V-115-020 - Allied Electronics $21.90 two wire 20 amp. -31 F to +104 F range.
Photo sensor. MSC Item Detail $11.47 three wire 15 amp. Outdoor service rated.
Multi function timer. MSC Item Detail $12.96 each. These can be configured for delay off and can work with the photo sensor as the triggering source or they can be set to work independently as well. I have used them many times and they are very versatile.
Metal weather proof box. MSC Item Detail $28.22 Unless your chickens grow opposable thumbs and big enough brains to be able to operate a screwdriver I seriously doubt they will get into it.
Being the photo sensor and the thermostat are both capable of being remotely mounted there should not be problems with chicken tampering.

I doubt you will find much else that is weather proof/chicken proof and can be simply wired (two and three wire control) with out considerably more electronics and electrical skills.

The quality and capacity of the wiring and overall design is of course very dependent on the person who does it obviously!
If he is being outsmarted by chickens and gets his work undone by chickens it may be saying a lot more about his skills and abilities than he may care to admit to!

6th January 2010 09:10 PM

Topsoil,

I sent you a PM.

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