Automatic door opener project

[Boogity]

Hi everyone - I'm new here so please be patient with me. When I retired from mechanical engineering 10 years ago I became a mini-farmer. The farm is mini, not me .

Many farmers need assistance with automating some things on the farm. One is an un-attended door operator. One designed to allow livestock to exit the barn or pen in the morning and to close the door in the evening when all animals are safely inside. My first project will be a chicken coop door with a 12VDC motor (+/- 3 amps) and controls. For something this small I envision using hobby shop motors and gears like slot cars or R/C cars.

I have considered many of the needs for this little project and I have come to the conclusion that a typical garage door opener type of control would be perfect. I would have to add some additional circuitry to actuate the opener at an adjustable time in the morning and to close it at an adjustable time in the evening. This timing devise may need to be "light activated" so the door will open at dawn and close at dusk. The ideal design would have both activation options.

I do not know much about electronics but I'm certain that a garage door opener PCB could be used and controlled by this "timing" circuit board.

Another important consideration is that the door drive motor and the controls must be 12VDC powered. So therefore a low current circuit and a high current circuit is necessary. I would use a 12VDC wet cell or gel cell storage battery and a solar charger for un-attended operation when an AC electric source is not available.

Can someone provide instructions on how to make these controls?

Your thoughts and comments are welcome.

Thanks, Larry

 

[killivolt]

adjustable time in the morning and to close it at an adjustable time in the evening. This timing devise may need to be "light activated" so the door will open at dawn and close at dusk. The ideal design would have both activation options.


Can someone provide instructions on how to make these controls?

Your thoughts and comments are welcome.

Thanks, Larry

What happens if an animal is late, After dusk?

 

[gary350]

My father owns a farm we have cattle guards on the roads to keep them in and we can drive in and out. He has pigs, cow, chickens, ginnies.

This is what I would do. Timers will work you to death keep you busy resetting them as the days get longer and longer then shorter and shorter as the seasons change so I would not use times.

You need a sun activited switch photo cell. They are available at any industrial electrical supply store in most towns. They cost about $20. It is the same thing that turns on city street lights when the sun goes down and turns them off when the sun comes up. It has a sensitity adjustment.

I have noticed that our chickens go in the chicken house on their own when the sun goes down. It is not completely dark yet and the chickens are all in the chicken house already. So I think a servo motor and a photo switch will do the job. You can also buy louver vent servo motors at any industrial electrical supply store they are used on furnaces and air vents and boilers to open and close or move something. Attach the servo to the door so when the sun goes down the door closes, when the sun comes up the door opens. That should work fine. If your chickens are not all inside the house when the door closes then you may want to put a delay timer relay on the servo motor so when the photo electric cell tells the motor to close the door there is a time delay. Potter & Brunfield sells adjustable timer relays get one with a 20 minute delay and you can turn the dial to 10 minutes or what every is needed. You will not need a timer in the morning.

Buy a 12 VDC to 120 VAC inverter to converter your 12 volt power supply to 120 volts. You can buy a 300 watt unit for $30 on ebay or any of those foreign tool stores like Northern Tool. The photo cell has 3 wires and is very low power. The servo motor is low power too only about 1 amp. Servo motor comes with an adjustable arm so you can set it for any stroke or lenght you need.

McMaster Carr and WW Grainger both sell what you need and you can order online.

I have been searching both MMC and WWG for the servo motor but so far I have not found it. I know they sell them because I have orders them before. when I find the servos, relays, photo cells I will post a link here.



Photo switch $10 https://www.grainger.com/Grainger/items/6P007?BaseItem=1JLG4


Timer relay. This is the type relay you need but you need. Pick one with about 15 to 20 minute delay. **broken link removed**

I can not find a pic of the servo you need. We have several of these at work. We have them on the building vents. When the fan comes on the servo opens the louver vents. We also have these servos on 11 large furnaces. The furnace ignites on low then when the control show the furnace is light the servo opens the gas valve and the air valve both at the same time to power up to 1,000,000. BTUs. These are very simple servos they have a 180 deg rotation with an arm that is about 6" long with several taps to conncet an arm that can open a door. The servos box is about 4" x 4" x 4" square 120 volts AC. I don't know the name and model number so I am not able to find a pic online. The way this servo works is the arm stay retracted all the time with 120 volts on it the motor hits a limit switch built inside and it stops in the netural position. The photo switch triggers it to rotate shen the sun goes down it rotates 180 degrees to close you chicken house door. After it rotates the full 180 degrees it hits another limit switch build inside that stops it there. When the sun comes up the photo switch turn off the trigger to the servo so it returns to neutral position that will open the door the next morning.

 

[killivolt]

You can also buy 120 volt servo motors

Apart from everything else I thought this was not an option ?

 

[killivolt]

Apart from everything else I thought this was not an option ?

If this is not an option I would use a motor out of the Junk Yard from an old car.

The actuator would slide back in forth. You would deploy it with a light sensor which is easily built from a light sensing diode. But, I'm sure there are a lot of kits out there you can get cheaply.

After that it's a matter of stopping the motor travel with a switch or sensor. And restarting it in the opposite direction. Heck even for that matter you could deploy it using the actual assembly from the car and put a motor and cam assemble to rock the switch back and forth.

 

[killivolt]

https://www.ozitronics.com/docs/k79a.pdf

**broken link removed**

Here is one of them.

kv

 

[Boncuk]

Hi Larry,

I used to breed racing pigeons and control in and out of the house using thin steel rods (bicycle spokes) suspended from a horizontal bar to swing freely forwards and backwards with little sideways movement only.

Pigeons (and chicken) learn pretty fast to push against the rods to get in and out. (Pigeons train flying circles over the pigeon house)

Keeping pigeons under close watch is necessary for their survival not to fall victim to a hawk diving into the circle.

The steel bars can be locked from the bottom by blocking them from either side, offering three options: in only, out only and completely closed.

If you block for "in only" time is of no importance, since late chicken can get into the house without problems.

I suggest to block the entrance for a certain time from getting out and an hour later (timer triggered by dawn switch) block it both ways to keep foxes out of the henhouse.

It won't do any good to know all chicken are at home, not knowing that a fox is having a party with them. The fox will wait until morning dusk for the hatch to open.

Since you are a mechanics engineer you will certainly design an opening/closing mechanism which requires power only for activation (both ways, like landing gear operation for aircraft with over-the-center-locking)

I guess geared toy motors are strong enough to raise a blocking bar. As there is no hurry to lock the hatch you might use a worm gear for high torque.

Boncuk

 

[killivolt]

That's a good one. I like it.


kv

Edit: Funny, I had some good looking pigeons once. Story is of 2 falcons a larger falcon was waiting atop the light pole just underneath was the roost. A late pigeon was under the carport not knowing weather to fly or not impatiently seeing me he took off.

As he approached the stoop the falcon left the pole the pigeon diverted to attempt a landing in a nearby tree. The falcon swooped up and back down on the Pigeon striking him and he spun slowly to the ground. My best looking bird was dead. I thought.

About that time another smaller falcon proceeded to launch himself up and down in an effort to win the prize a battle ensued. Clashing the larger bird with vigor. Suddenly my bird get's up and staggers a bit and realizes he's not dinner and heads back to the carport. Taking refuge until morning.

kv

 

[Boogity]

What happens if an animal is late, After dusk?

killivolt - I had to laugh at your reply. That's exactly what I asked when I first heard about the need for an automated door. The livestock seem to know when to head for the "house" each evening - especially chickens.

<snip> I used to breed racing pigeons and control in and out of the house using thin steel rods (bicycle spokes) suspended from a horizontal bar to swing freely forwards and backwards with little sideways movement only. <snip> Boncuk

Are you saying that you had many spokes hanging down in front of the door opening? Sort of like we would hang beads in front of a door in a house? What kind of blockage did you use at the bottom to make the door out-swing, in-swing, or no-swing? I think it is a very interesting concept but I cannot picture it in my mind.

I have the mechanical design part of this project worked out fairly well with a steel guillotine type door, a steel door frame/track, and a tiny 12VDC motor.
What I'm looking for is the electronic design to make the whole thing work.

Yes I'm aware that a sun activated switch may be necessary.

Anyone out there looking for a design project?

 

[mbarazeen]

you can use two LDR circuits for different intensities and delay adjustments as shown in the pic. some one can post the diagram?

 

[killivolt]

Maybe this is what your looking for ?

**broken link removed**

Here seems to be a good one and you can build 2 of these boards one for open and one for closed.

I would add 2 lever action switches both are ( N.C.)

1.When light activates the first board starts the motor bringing the travel of the door all the way up to the top switch which will open it contacts stopping the motor.

2. The second board sensing dark brings the door down until the door reaches bottom which opens bottom switch contacts allowing for the start of the morning session.

Reverse polarity ( +- / -+) for the opposite direction of motor.

You might want to check into some used refrigerator door switches these are common and you can cut out a square hole to mount them in the channel. Make sure you look for the type that swing closed and not the push button ones.

Get the Picture... Cluck- Cluck


kv

 

[mbarazeen]

also one pint to be noted, both signals should not overlap, ie should not appear at the same time.(open & close, open command should go off before close command comes in action and vise versa)
when a latching circuit is used it can be set and reset by pulses only. the last received pulse will be latched and no fear of overlapping.

OR the limit switches that are used for motor can be wired in such a way to enable either open or close circuit only one at a time.