Comments on: Auto Coop Door II – Antenna

By: Leon

Leon — Wed, 24 Feb 2010 03:13:09 +0000

Thanks Bob. I think I’ve got it wired properly, but yes, I was still (strangely) thinking that I needed to switch the 3-4A with the timer rather than just the high/low sense wire. Cheers!
Leon

By: Bob

Bob — Wed, 24 Feb 2010 03:07:01 +0000

Hi Leon,
I sent you the link to the Radio Shack chokes.
I think you are connecting things incorrectly. I say that because you are concerned about the 3- 4 amps. This tells me that you may have the timer switching the antenna’s motor, not the the trigger? You need to connect the antenna’s red and black leads DIRECTLY to your power source and leave it there. The only thing that the timer controls is the antenna’s trigger circuit. This requires micro amps to do. Therefore a choke as the one in the RS link will be more than large enough.

Bob

By: Leon

Leon — Tue, 23 Feb 2010 04:01:03 +0000

Hi Guys,
Well I rigged up the ST01C with an inductor from my parts bin – about 1.5mm varnished copper wire wrapped maybe 30-40 times round an iron ring. Soldered it to the black lead from the timer and it definitely didn’t do the trick! I had the timer resetting every single time the antenna pulled closed.
Chris, that RadioShack unit you linked me to – is that what you’re using?? Doesn’t look like it’ll take 3 or 4A of current for 10-20s while the door moves.
Cheers,
Leon

By: Bob

Bob — Mon, 08 Feb 2010 16:24:45 +0000

Hey Chris,
Hope its a pleasure trip, not that “W” word

Anyway, from an electronics viewpoint and rule, the most efficient place to install a choke or any suppression device is as close as possible to the device that you are protecting. But if you are just isolating the timer from the motor, I would see no harm with placing it near the motor. BUT, if you want to protect the timer from ANY and ALL stray RFI that may get induced into the timer (strong radio waves or other noise transmitted RF) you are always better off to place the suppression device right at the device you want to protect (the timer). I could get into more detail but I will stop here

Bob

By: chris

chris — Mon, 08 Feb 2010 14:51:11 +0000

I will repond more in a day or two, but basically the choke should be put as close to the motor to be as effective as possible,also, not knowing the exacts about this choke, because it is sealed in a heat tape set up, it appears to be several things on a small pc board, they also said it would work with ac or dc and any voltage you were using at the motor.
I am actually traveling at the moment, hense the delay in response, but after arriving back home in a few days I will check the choke closer and perhaps post some pics…………. Chris

By: Bob

Bob — Tue, 02 Feb 2010 17:13:13 +0000

Leon,

I’m sure that Chris will chime in on the details of what Intermatic sent him on chokes. But the connection is quite simple. It is in series with the wire that goes to the antenna’s trigger. However, I took it one more step. I figure that I might as well protect the both the input and the output of the timer as well. I am a Ham radio operator and my antenna system is very near the coop. From past experiences when it was near my house, my RF signal can have the capability to “get into things”.

If you have a Radio Shack store near by, you can get a couple of chokes for $1.39 each. Here is a link. You should be able to find them easily from other sources as well.
http://www.radioshack.com/product/index.jsp?productId=2103978

On the ST01 timer, you will only be dealing with two wires.The black and blue. Because it is basically a simple on off switch, it does not matter which color goes where. So if you choose to use RF choke perfection, simply place them in series directly on the switch’s wires.

As far as your charging calculations go, looks like you got the math down good. But I’m weak when it comes to solar panel expectations. I will pose your question to my Ham radio electronic gurus.

By: Leon

Leon — Tue, 02 Feb 2010 12:59:15 +0000

Could I get a description or photo please of how to rig up the RF choke with the ST01C? I’ve ordered the timer from a US ebay seller after not being able to find an electrical wholesaler locally who’d even heard of Intermatic!
And any advice on how powerful a solar panel to use would be appreciated…
Assuming one up, one down per day and negligible else, that’s say 1 minute at say 4Amps, ~0.08Ah. Call it 0.1Ah. Three hours of effective sunlight (winter, foggy morning/cloudy day) at 50mA would be 0.15Ah – enough to make up for the losses in charging. 50mA at 12V = 0.6W solar panel needed?
Funny thing is that a 5W panel is a very similar price to the 30-100mA type “car battery maintainer” type panels. Any lessons already learnt on this would be appreciated.
Leon

By: Bob

Bob — Mon, 01 Feb 2010 17:40:41 +0000

Hey Leon, Great idea. But now you do not have an excuse to make periodic fresh chicken soup

Good on the Intermatic ST01C timer. I installed mine a couple of days ago and so far I love it. I set the timer to think that dusk is 30 min later so that it is 100% dark outside before the door closes.

Thanks again Chris for finding this timer. I hope all the folks read down to these posts before going with the photo cell idea that I had. It does work, but I see no need for it now that there is a self adjusting astronomical timer available that does not require household current to run. We just need to make a habit and change out the lithium battery before it dies. Maybe every year to be safe. If I get real bored someday, I will put together a little 3v regulator chip that can run the timer from the 12 volt battery. That way no lithium battery in the timer would be needed.

Bob

By: Leon

Leon — Mon, 01 Feb 2010 13:32:09 +0000

Hey folks (especially Chris and Bob),
The antenna idea is perfect – brilliant! – full marks for appropriate engineering to whoever came up with that idea. I liked the idea of the electric window closer too since they often have the safety stop trigger which might save a tardy chicken from being squashed by the descending door.
But I think I’ve solved that problem a different way and I’d like to share my own minor improvement to this team effort. Instead of attaching the antenna tip to something bolted to the sliding door, I used some wire (about 1.5mm diameter). I drilled two holes in the top of my door about 15cm apart, tapped a 3mm thread into the tip of the antenna and put a short 3mm bolt into it (with a washer), leaving about 1cm of thread exposed. I then twisted the wire tightly around the exposed thread on the bolt and took the ends down to the two holes in top of the sliding door. Now the door lifts under the force of the antenna motor, but descends under the force of gravity – plus a bit of pushing because the wire is fairly stiff. But if I put my hand under the door as it tries to close the last 10cm (chicken injury zone) the wire simply bends and the antenna continues pushing through to its normal stop point. The amount of downwards pressure seems light enough to give the chicken a push, but not enough to trap or squash it.
I look forward to getting my hands on an Intermatic ST01C soon and a small solar panel to charge the battery too, but for now it’s running fine with a 350mA 12V smart charger on a 7Ah 12V lead acid battery to power the antenna motor, and a 150mA 9V DC plug pack (puts out just under 10V open circuit, so you don’t need a 12V source to trigger the antenna) I had lying around on a mains timer as the trigger – all stuff I already had. In fact, the only piece I had to buy for this (so far) was the antenna and that was $15 from an auto wrecker. And it’s working great
Thanks again everybody!

By: Bob

Bob — Mon, 18 Jan 2010 23:51:44 +0000

Cool, thanks Chris.

I have some RFI suppressors (chokes) in my parts bin. I’m a Ham radio operator and sometimes RFI will get into things.

Thanks for the heads up,

Bob