Tell me where to buy / how to make a DC light timer
September 8, 2013 5:06 PM   Subscribe

Our chickens [!] have trouble hopping up on their roost at dusk. We have glued a keychain LED to the inside of the coop and have been turning it on every night, and then off when they are roosting. I would like to have this turn on automatically at dusk and then off again an hour later. If this were AC I would buy a timer from the dollar store. For DC do I need to build something?

If we had a single power outlet on the outside of our house, we would plug in a trouble light and use a timer, but we don't have any outlets outside. If we wanted a DC light to turn on at dusk and stay on, I would put a solar garden stake light in/on the coop somehow.

How do I make a light turn on at dusk and then turn off in an hour or so? Solar would be best, but I have rechargeable AAs, AAAs, and 18650s. One little led run off a 3.7v cr2016[x2] is plenty bright for this operation, but if there is a sub-$20 item that I could buy, that would be good, too.

The plan that I have right now is probably stupid - modify a solar garden stake to charge a battery with a much smaller capacity so that the battery drains very quickly.

[I have just started my first teaching position, so suggestions with arduinos and 555 timers, while welcome, will be ignored for at least a few months.]
posted by Acari to Technology (8 answers total) 1 user marked this as a favorite
While this isn't going to address your question - did you just get your chickens this spring? Our chickens were babies in April and half of them still sleep in a pile in one of their nest boxes. The other half roost up on top of a wall in the coop with no light to help them. Some chickens just don't roost.
posted by checkitnice at 5:21 PM on September 8, 2013

You don't really say how much light they need - would glow in the dark paint be an option? I suspect you could balance the amount of light received in the day while the paint "charges" with the amount of paint used to get about an hours worth of light at dusk...

I haven't used this kind of paint in years but when I did I had a jar of paint which sat on my desk and provided a healthy green glow when the lights went out...the concentration of phosphorescent particles in these paints vary widely so if you go this route make sure you get the good stuff if you want lots of light...

If that doesn't work, rather than using a smaller capacity battery in the solar stake, why not use more LEDs (i.e. string two stakes together with only one battery - or attach another LED in parallel to the first)? This will drain faster and give more light - it also won't cause any issues with the charging circuitry (if there is any...)
posted by NoDef at 5:44 PM on September 8, 2013

Best answer: What about a timer like this? Seems to fulfill your exact need. Looks like it can switch even AC on/off, but is fundamentally a relay switch driven by a 12V power supply. This in conjunction with a lantern battery could work?
posted by suedehead at 6:38 PM on September 8, 2013

Forcing tech to do what you want it to is fine, any way you do it. I have seen products designed with this philosophy. It's frowned upon by pros, but it works. Running down the battery fast is in this category, but it's legit if you can figure out how large the load needs to be and you are willing to tolerate variability in it as the batteries age.

Your issue with a straight timer is the variable dusk time, which eliminates a timer, unless you want to program it monthly. Triggering on dusk is the way to go.

Find a hacker (or ham radio friend.) Get them (or you) to build a timer based on a 555 timer IC that is triggered by the LED coming on and that turns off the light an hour or so later. $10 and a case of beer and you're good. Radio Shack has all the parts.
posted by FauxScot at 7:17 PM on September 8, 2013

Best answer: Acari, we handle this with a string of battery-powered Christmas lights that have a built-in timer. I can't remember where we got them, but they're basically these. It's really quite festive in their coop for a few hours after dark. Of course, this doesn't solve your variable-dusk problem; we just reprogram it every month or so.
posted by waldo at 7:57 PM on September 8, 2013

Can you put a motion sensor flood light on your house run to AC that will illuminate the coop sufficiently from a distance? Those turn off on a timer.
posted by jeffamaphone at 8:02 PM on September 8, 2013

Response by poster: Those christmas lights and/or that timer were what I had just spent too much time trying to find. I'll probably go with the timer and rig up some kind of pretty led array so they can have a dance party in there.

The glow in the dark paint is maybe a good idea, and I have some left over from a project where I tried to train myself not to hit my head in the basement [failed], so maybe that gets thrown in as a bonus. I've heard that too many hours of light can be unkind to chickens, but this gitd paint is weak, so chances are they won't even notice.

The chickens are new, but they have learned to roost fairly quickly, and roost every night that I am home to light their way. If I come home late and they are sleeping on the ground, 1 minute of light shining on their roost is enough to convince them all to hop on up for the night. The timer is for the sake of consistency, since I don't believe they have a great capacity for nuanced learning and I don't want them to just decide that the floor is now the only place to sleep.
posted by Acari at 8:30 PM on September 8, 2013

I would worry that light in the evening would override their natural twilight bedtime triggers and make them LESS likely to go to bed. For example, I've always heard, from people who light the coop for egg production reasons, that you should turn the lights on earlier in the morning rather than leave them on later. The theory was that if it's well-lit past dusk, they won't go to bed, then when the timer switches off they are suddenly plunged into darkness and unable to get to bed. (Chickens in the dark are DUMB, as you've noticed.) So you might want to consider something that starts out not-super-bright and then gradually dims. Or, give them a little bit of time, and see if they figure it out on their own without a light.
posted by librarina at 7:56 PM on September 10, 2013 [1 favorite]

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