Chicken Door linear actuator

Thread Starter

wswarrior

Joined Nov 12, 2014
7
So I feel like I am close, but maybe not quite there yet. These linear actuators open and close based on the positive and negative flow of power. Just reverse the positive and negative and it opens or closes. So, I can use a photocell to actuate it one way, but how do I make it close? I mean I know i need a relay, but the photocell only connects the circuit one way. I am sure I am completely missing something. Am I even close? Trying to keep this 12V.

Motor: https://www.ebay.com/itm/2-18-Inch-...bs-LinearMotor-12V-with-Brackets/233704565557
Reverse Relay https://www.amazon.com/gp/product/B0879GGVPZ/ref=ox_sc_act_title_2?smid=A2OVMUS055KMW5
Photocell: https://www.amazon.com/Control-Switch-Switching-Sensor-Photocell/dp/B07QVC4J39/
 

crutschow

Joined Mar 14, 2008
26,726
You can use a DPDT relay to open the door when the photocell detects light and close the door when it becomes dark.
But you likely also need limit switches to turn the actuator off when the door reaches it's open or closed limit.

Below shows how a DPDT relay is used to reverse the power to the motor (which reverses the direction of the positive power, it's never negative power).
The diodes protect the relay contacts from any inductive spikes from the motor.

1612770557798.png
 

Thread Starter

wswarrior

Joined Nov 12, 2014
7
The nice thing about the actuator is that it has an internal limit switch. So what you are saying is that I have the right stuff. I just need to connect it together the right way and I should be good to go?
 

crutschow

Joined Mar 14, 2008
26,726
that I have the right stuff. I just need to connect it together the right way and I should be good to go?
Not exactly.
I show a DPDT relay, which only requires one input.
You posted a motor reversing switch which has two inputs (forward and reverse).
If you use that switch, then you will need a simple inverting circuit or relay to provide the two signals from the one photocell output signal.
 

Thread Starter

wswarrior

Joined Nov 12, 2014
7

crutschow

Joined Mar 14, 2008
26,726
300W 12v is outdoor lighting transformer that I am not using.
I assume that has an AC output.
You then need to convert that to 12Vdc with a bridge rectifier, and a large filter capacitor, which will give about 16Vdc output.
After that you use a regulator to drop it to 12Vdc.

Do you know how much current the actuator requires?
That will determine the type of regulator (switching or linear) that you need.
 

strantor

Joined Oct 3, 2010
5,505
I can't believe how often chicken coop doors come up on this site. No joke, it's probably in the top 5 most common FAQ. Maybe we need to have a sticky about it.

My chicken coop door auto closer has been failing lately and I end up having to out there and do it manually. I might need to adjust her allowance. Or use this as an early teaching moment about losing one's job to automation.
 

Marley

Joined Apr 4, 2016
409
My chicken house door controller is now on its MK3 design. You really don't want a door that is forceably opened or closed. Because if something gets in the way carnage can result. One got its leg caught in my first attempt - thankfully no long term damage to chicken or door!

All door operators need limit switches to stop it at the end of travel. I thought long and hard about this on my latest design. I wanted to limit the amount of wiring external to the control box and if possible not have external limit switches at all. My door is pulled up vertically by a small motor with a worm-drive gearbox. My solution was to mount the motor on a lever with springs to control the deflection and switches that operate on full deflection. So basically these springs measure the tension on the cord. Everything, motor and switches is enclosed in a rain-proof box.

So when the door closes (goes down), it stops when it gets to the bottom or when it hits an obstruction (when the cord goes slack). On opening it stops when it gets to the top and the cord goes much tighter than normal. This has the added advantage, which has happened recently, when the door got frozen shut overnight. Instead of burning out the motor it simply gives up.

All controlled by a light sensor. Which took some research - measuring the sensor when the chickens decide to call it a day (almost dark). I also have a 3-position switch: force open, auto, force closed. It uses a micro-controller so I won't go into the details of that here.
 

Thread Starter

wswarrior

Joined Nov 12, 2014
7
Just a note, all the linear actuators on ebay have internal limit switches. However, the more I dive into all this the more I feel like i am out of my depth. I really just want to buy the right parts, wire them together and have a solution, however seems like it is a lot more technical. No wonder the cheapest one you can find commercially is about $200.00. Sigh.. maybe I will just get my butt outta bed and open the door.
 
I keep pushing an "an astronomic timer". It calculates sunrise and sunset. At home, I have one that turns a light on 1/2 hour after dusk and off at 11:30pm.

Two SPDT relays gives you dynamic braking. It gives open, closed, brake, brake as the options. No power is consumed when the relays are at their limits. The limit switches are rated for the coil current. Automotive relays are typically used. You can buy a dual socket mostly wired.

You do need another spdt relay if you want a ON/OFF to be open/close.
 

strantor

Joined Oct 3, 2010
5,505
I keep pushing an "an astronomic timer". It calculates sunrise and sunset. At home, I have one that turns a light on 1/2 hour after dusk and off at 11:30pm.

Two SPDT relays gives you dynamic braking. It gives open, closed, brake, brake as the options. No power is consumed when the relays are at their limits. The limit switches are rated for the coil current. Automotive relays are typically used. You can buy a dual socket mostly wired.

You do need another spdt relay if you want a ON/OFF to be open/close.
Are you referring to a product, or something to build?

There is an arduino library for that. I looked into it when I was planning a sun-tracking solar panel. You feed it your lat/long, date, time, and it calculates where & when the sun will rise & fall, or where in the sky it will be at any given time, year round. You wouldn't need all data that for a chicken coop door, but it still calculates it. You could just use the sunrise/ sunset times and put in a fixed offset (close X minutes before sunset, open Y minutes after sunrise).

I agree that would be a more solid solution than measuring ambient light.
 
Aliexpress generally has this: https://www.geya.net/digital-timer-switch/digital-timer-switch-thc-30a-2c-220v/

There are a few "smart relays" that have the library and they will operate on DC.

The timer I have plugs into a US 120 wall receptacle and provides a switched wall receptacal. It has a few coin cella for bbackup.

Idec's smart relay has it.

https://sprinklersupplystore.com/products/controlscape-astronomical-relay-timer

Flowcode has it https://www.matrixtsl.com/wiki/index.php?title=Component:_BBC_Weather_Forecast_(Comms:_IoT/Cloud) but with internet access.

Siemens LOGO seems to have it. https://support.industry.siemens.co...ronomic-clock-issue/195140?page=0&pageSize=10

I think you can produce a webpage with LOGO.
 
I bought that Geya Astronomical Timer THC-30A THC-30B and it doesn't work- you enter latitude/date/time and it just doesn't correct sunrise/sunset times. The chinese datasheet is so terrible I got a Russian one and translated, but still no idea why it doesn't work properly. Contacted Geya and they demanded a video which is a bit ridiculous for missing sunrise/sunset times. I think the firmware is fake.
Ended up writing Arduino code for calculating sunrise/sunset, it was fun and not too painful.
edit: fixed wrong model number
 
Last edited:
Sorry I gave the wrong part number it is astronomical 110V 30A din-rail THC-30B. For me it doesn't work and many people could not get it working. I think the firmware is fake or just silly, because for some stupid reason you must have at one on/off time programmed. I say not necessary- because it's supposed to know sunrise/sunset times!
The Russian manual (аналогичнрго relay TDM ELECTRIC TE-C TЭ-AC TE-AC) said you program an on/off time close to your sunrise/sunset time (for that day) and the unit then tracks and shifts that time accordingly. But I've tried everything and it just acts like a timer only. Pulled my hair out because the English manuals are the worst I've ever seen.
 
Top