I’m very new to this level of the electronics world. I am building a door that will raise and lower on a chicken coop. The original door I designed was 9.62 lbs. I can change some things out to get it down to 7.6 lbs. A friend said I should use a stepper motor to keep from having to use limit switches. So, here is my problem. Since the motor and control unit will be located on the exterior of the coop, I will be going from the top of the door, up 2-foot to a pulley and turning horizontal approximately 1’-6" through the exterior of the coop.
So here is what I need help with; what size stepper motor (12V system run off a solar panel and 12A/h lead acid battery) do I need to lift this weight?
Also, I’m looking for something to use as a winch drum (spool) and have only found one plastic part?
The door will be operated by a photocell with a time delay of 1 hour. 1 hour after sunup the door will open, 1 hour after sundown the door will close. Chickens love to have that warm and fuzzy feeling… just not from a raccoon.
I’m going to use a Redboard for the controls, which will include turning a LED light strip on after 5 hours of the door closed. Funny thing about chickens… they like 16-18 hours of “light” a day to keep their laying cycle regular. So, the light will keep them laying in the winter.
Thanks for the idea of the grille motor. I just hate to add another power source since AT&T gave me this nice battery.
Unless you plan to also have some latching mechanism or a counterweight, any motor will need to remain near fully powered during the day just to hold the door up. That’s probably not a desirable thing. Can you change the way the door opens ? I’m assuming a “guillotine style” door. A door that slides open (side-side) like the below is probably the easiest to mechanize.
The size of the motor needed will (of course) depend on the type above but also on the gearing. A small (torque-wise) motor can lift a heavy door w/the proper gear reduction. It’ll just take a “long” time. How quickly must the door open ?
Holding power on the door was another worry. The house was designed for a door to go up and down. I’d have to do some thinking to make it go side ways.
I’m starting to think it would be better if I went with a standard geared motor and a couple of limit switches? Would that get me away from the power having to be on it when it’s in the up position?
Also, there is no certain speed it needs to open/close. Slower is probably better.
Consider a linear actuator instead – basically a motor (stepper or brushed) driving a threaded rod with a traveling nut. They are very powerful and hold position when not powered up. You can buy them or make your own. There are a number of nice DIY tutorials on the web that show how to make them.
Use a motor with limit switches. Using steppers simply to avoid limit switches is poor engineering judgement.It adds power consumption and complexity for no real benefit, since you need at least one limit switch so the stepper knows where it is anyway.
Winching the door up and down will work, but raccoons can learn to lift the door up if it is not locked. They learned how to open my bin of scratch grain until I left the bail up to lock the lid down. A worm drive or even a simple threaded rod will keep them from being able to push the door open.
I like the idea of a worm gear. Solves the locking problem too. McMaster - Carr has the worm rod. I can JB Weld a nut and a coupler for the stepper motor. Probably can go with a smaller motor. I just have to redesign my door and how the motor is set up.
For linear actuators I use 1/4 x 20 threaded rod, which you can buy at just about any hardware or home improvement store, in lengths up to about 4 feet.
My original motor above uses 3 volts with a external power jack, so your 12 volt battery would work with a step down method.
Amazon has various lengths of actuators which are a complete package with built in limit switches to build around. Now it is time to develop your logic of sensing sun light and one hour switch off time, or On to activate a motor.
Stop laughing, the advantage of my approach is the chickens get use to the sound of a rotisserie. :lol:
After “incubating” a chicken auto-door approach I would use the lower current 3v battery operated BBQ motor $22. Using D cells could power the whole setup for years without replacement. Cost effective, no need for a solar recharging setup. I would use a self secure door method. My approach avoids slide doors that might hang up in the track. Raccoons can be tricky devils so nothing should be grab-able.
The motor logic could use limit switches or current sensing so when the door hits the stops or an object the brief current surge could turn the motor off. All the operating logic would be a fun and practical build around the Arduino.
This $5 board below reads like it “might” stand alone and do the basic stuff for the 1-hour on/off timer triggering, cheap enough from China to buy one for testing. May not need a 555 & CdS cell for dark/light trip points.
Mine worked well enough, until the battery died. Then, it needed to be “programmed,” a simple procedure of button pushing.
I spoke with the manufacturer, once, about adding an audio signal for a low-battery condition. It just has an LED for that function and that was not enough to get my attention. He was very nice.
Mine came for free with the chickens. Funny how they knew the exact moment of darkness to go into the coop.
Ambient light, from streetlights, etc., can interfere with the light sensor.
Protecting chickens from predators is an on-going concern. I’m not always home to watch for my chickens that’s why an automatic door closer is a great help. Hungry animals come across the lawn, they dig under fences and they fly into our pens and we know that there is no fence that is predator proof.
