They're a great starter kit for the average home owner who wants to water their garden without having to remember.

My wife went in for a surgery (long time ago). She asked me to not let her flowers die. She convalesced at her mom's house for six weeks.

I promised to keep her garden alive. So what was the first thing I did? Forget to water her hanging plants. Realizing I was being forgetful I went to the local big box store and bought a drip irrigation kit which consisted of a single unit and a single valve and a 9V battery. Screwed it to the hose bib and ran the tubing up to her plants. Fortunately for my marriage the plants recovered. When she came home she found her plants lusher than she had ever seen them. So those cheap dip systems have a place.

The TS wants to use something battery powered. Likely it's at a low voltage. 9V? Probably hard to find. 3V? More than plentiful. So a momentary positive pulse (assuming red and black wires, positive on the red wire, negative on the black) will open the valve and it will hold its setting. Suppose the timer is set to run for 10 minutes. At the end of the cycle a negative pulse (negative on the RED wire) will set the valve back to the closed position. These valves are not motorized, they are purely set or reset same as a latching relay. This is where @MisterBill2's suggestion of air comes into practicality. A valve, albeit designed for water can deliver a blast of air (I wouldn't exceed 80 lbs. pressure) can open an air cylinder to drop a shelf latch allowing the shelf to fall. The impracticality of it is that a source of compressed air is needed. A second, negative, pulse will be needed to shut the airflow off. Depending on the size of the air cylinder lower pressure would be plenty adequate to drop a shelf.

I've seen videos of people who turn an old refrigerator compressor into an air compressor but the rate of compression is low. To run the fridge compressor to fill an air tank you'd need a safety shutoff switch to prevent the tank from being over-pressurized. While air is a good idea, there are the peripherals that need to be considered. (sound familiar?)

{from a different thread}
I am the one who considers the secondary result to those who only focus on their idea of the immediate fix, not realizing the secondary results. And those secondary results are what we get stuck with. Sometimes not so very good as we might wish.

"There are those who find solutions to the problem, and then there are those who only find problems with the solution."

So IF a compressor is used then there's going to be 120VAC (or 240VAC) by the feeder, why not just go with a 24VAC sprinkler controller? IF battery powered, a drip irrigation controller would need a couple of batteries connected to a very low voltage relay or transistor to handle switching the higher voltage needed for the solenoids. Plus a (likely) 12V battery to actuate the solenoids. While all this is doable it IS going to take some engineering.
1) How long is a solenoid to be powered?
2) What voltage is the solenoid powered at?
3) How much current will be required to successfully pull the plunger of the solenoid to allow the shelf to drop?
4) What means of control will be used to actuate the solenoids?
4a) If battery powered, where can you find a relay that can both operate on the low battery voltage AND handle the amount of current needed by the solenoid?
4b) If AC powered, can the AC power be used both for triggering the relay AND enough power to actuate the solenoid?
5) How much money does the TS (Thread Starter) want to spend on this project?
6) WHAT IF the system fails either due to a power failure, loss of power (pulled plug or broken cord)? What kind of alarm might be needed?

I'd guess there are other things that need to be considered as well, things I haven't thought of. So think of this as a starting point.

 

First of all, certainly a retired refrigeration compressor can provide a very useful air power source, the method is to have an air tank to provide the required flow, which is always greater than the compressor can deliver. Then added a pressure switch to switch off when the tank reaches som set pressure. And a check valve and unloader valve so the compressor does not get stalled trying to start against pressure.
Air actuation does not require an air cylinder, those are expensive devices. An inflatable air bag can provide the motion required very well, as I described much earlier. AND, the solenoid air valve can be back at the control point, eliminating a lot of wiring. And a simple 24 volt transformer can power simple normally closed water valves used instead for compressed air. Probably those valves will work as well on 12 volts DC, if battery operation is required.

 

Again, the TS wants battery power. I will assume that there is either no AC there or the TS does not want to use it. If there WERE AC there then going with all that setup for a compressor, tank, air lines, pressure cutoff switch and blowdown valve will get a whole lot more complex. Not to mention the control valves. But like you said, a sprinkler valve may work just as well as an air valve. I never said it was a bad idea. Just going with the KISS discipline - "Keep It Stupidly Simple". Sometimes the simplest approaches are the best.

In the end it's up to the TS to decide which direction they want to take. I've offered my idea. Others have offered theirs. They're out there for consideration. So is your idea. Though I really like the idea of an inflatable bladder that can knock a pin out of a shelf and allow it to fall. Kudos for that. It's an excellent idea. If one wants to go with all that extra stuff.

 

Probably those valves will work as well on 12 volts DC, if battery operation is required.

Y'know, I have some old valves laying around. I'll see if they power up on 12VDC. Will let you know later tonight. Right now I'm dealing with a sudden family issue, not to mention a cabinet I have to get built by this weekend.

So why am I here wasting my time ? ? ?

 

Last comment for the day. Come this evening - maybe.

Looking at your drawing:

A latching solenoid will also need the reverse pulse to close it. Or am I misunderstanding something?

 

The solenoids L1 - L6 are not a latching type. The lable meant a "latch" that holds the shelf operated by a solenoid.
I will edit that for clarity.

 

After further research I found that the irrigation solenoids recommended for that Timer operate from 6 to 12 volts with a minimum 10ms pulse to activate.
According to the specs on the Timer it says it provides a 11 volt pulse.
With that info, simplifying the circuit as shown below may be possible.

 

Actually, I was visualizing an air filled bladder under a shelf hinged along one edge, so that as the bladder inflates the shelf tips and the treats fall off. Then when it deflates the shelf returns to level. Nothing to reset. No pin to lose.

 

Almost as promised, I took one of those 24VAC sprinkler valves I have as extras that were removed from an older system and tested them using a 12V SLA battery who's voltage at rest was 12.8V. When the solenoid leads were touched to the battery the solenoid definitely kicked in. Watching the voltage while energized the battery voltage fell to 10.6V and the solenoid held firmly. I tried blowing air through mine but I guess it takes more air pressure to open than I can develop with my lungs. And I'm not going to go out into the garage and build a test rig just to answer the question 'will enough air pressure open the valve?' For now I'll assume it will.

On @MisterBill2's idea of using an air bag to hold the shelf up and to let it fall, then when re-pressurized the shelf will rise again seems like a fairly good idea. But I still like the idea of a latch that can be pulled to drop the shelf. That way it doesn't take any energy to hold the shelf up. Just enough power to trip a latch that will drop the shelf. The user can reset the shelf when restocking the hay. I mean "What the Hay?!"

 

Most water valves, and a lot of compressed air valves, all use a similar scheme, which is a diaphram held closed by the pressure of the inlet supply, plus a small amount of pressure supplied by the operating plunger, which closes the quite small opening that allows the pressure to hold the valve closed, to release that pressure to the downstream side when the plunger is retracted. It is really a brilliant design as far as the opening and closing process. So for common water control applications it will take a few PSI to open the valve. A similar, but more elaborate, scheme is used for many valves that control natural gas for heating systems.

And my concept for dumping the shelf was that the empty air bladder would inflate and tip the shelf, rather than deflate and release it. So the faster action would be to dispense the horse treat while the much slower deflating would be the reset action.

 

Most water valves, and a lot of compressed air valves, all use a similar scheme, which is a diaphram held closed by the pressure of the inlet supply, plus a small amount of pressure supplied by the operating plunger, which closes the quite small opening that allows the pressure to hold the valve closed, to release that pressure to the downstream side when the plunger is retracted. It is really a brilliant design as far as the opening and closing process. So for common water control applications it will take a few PSI to open the valve. A similar, but more elaborate, scheme is used for many valves that control natural gas for heating systems.

And my concept for dumping the shelf was that the empty air bladder would inflate and tip the shelf, rather than deflate and release it. So the faster action would be to dispense the horse treat while the much slower deflating would be the reset action.

Sounds interesting. Now if only you had a way of drawing and posting a picture. From what I gather the TS wants to put hay on the shelves. Tipping a large shelf over to dump the hay load - well, I'm not able to imagine that. Perhaps a teeter shelf with sufficient weight to hold the load but easily tipped over. A counterweight on the bottom could swing it back into position when the bag deflates maybe ? ? ?

When I was in elementary school I watched them raise a roof adjacent to a trailer. They did it with a giant air bag. Once the roof was where they wanted it they braced it and deflated the bag. There's a lot of potential in air pressure. Just 2 pounds per square inch on a car port my dad and I built, 432 square feet, so if my math is right 62,208 square inches. At just two pounds of pressure a roof weighing less than 124,416 pounds would easily blow off.

What I'm envisioning is a car or truck tire inner tube cut and the ends are glued and clamped shut at each cut end forming a large air bag. But that's going to be a lot of air in volume, at least for what I'm imagining.

 

Here's my imagination at work:

It WILL depend on exactly where the hay is loaded. It wouldn't require much lift, just enough for the top of the hay to overcome the counterbalance and the shelf will rotate 90 degrees, dumping the hay. Then the counterbalance will swing the shelf back to the reset position. When the bag deflates the shelf will be fully ready for another hay load. This doesn't need to happen fast. A slow leak can let the bag reset. Hay will be loaded once in the morning and the system will deliver the hay throughout the day.

I still think a compressor, tank and valves along with the timer will have to be AC powered.

 

I have been following this with a combination of gratitude for all of the people helping me and my horse, and some dawning understanding.

I think what I have learned, is I could possibly save myself some work if I found some 3v solenoids, rather than the 12v I mentioned above. After some Googling, I came across these https://probots.co.in/lockit-3v-electric-door-lock-for-cabinet-locker-safe.html and since they run on 3v instead of 12v, I think. perhaps they might work with the sprinkler controller without an additional circuit?

I have included a pic of my mare, Chanel, so you can see her sweet face

 

I think. perhaps they might work with the sprinkler controller without an additional circuit?

It just might if the timer sends out a long enough pulse to activate the solenoid.
I like Chanel's sweet face too.

 

I was considering either a chunk of fat bike inner tube or a smaller motorcycle inner tube. The truck tube section that I have is much to thick. But it might be a construction vehicle tube, all I found was a bit of it. A truck or car tube would be much too big.

 

The problem with a shelf that self-resets, is that in order to have multiple feedings in a box, I would have to make it horizontal, which takes up too much space in the stall, compared to one that goes vertical. If the shelves drop from lowest to highest then the lowest shelf is out of the way for the next feeding.

After reading all of the great help here, I am going to try those 3v cabinet locks with the off the shelf irrigation device and see if I can make that work. If I can't, then I will try something else!

It will probably take me a couple of weeks to get everything delivered and test the compatibility. I will report back with what I find out!

 

For the tilting shelf scheme, the shelves are arranged in a vertical sequence, with the hinge at the front edge. The top shelf dumps first so that the load is not able to catch on the lower shelves because they are still full of treat. The scheme was carefully thought out, just inadequately explained.
It seems that many are not good mind readers. That is a common affliction here. Sorry about that!

 

Why would the top shelf dump first?

 

I'm just going to throw out the possibility of using WiFi switches; timers can be set using smart speakers, or you could operate them remotely over the internet. As for solenoids, how about some kind of gear motor plus a limit switch (if necessary) to pull a cord; barbecue rotisserie motors are common items at thrift stores, or there's other common appliances like electric drills, kitchen mixers and can openers.

 

Consider that all of this will be installed in a horse barn, not a hobby experimenters shop.

Why would the top shelf dump first?

The top shelf would be selected to dump first so that none of what was dumped would catch on the lower shelves, because they would still be full. AS I ALREADY EXPLAINED. It would work because instead of dropping, the shelf is tipped up, with the hinge at the outer edge. If you have ever seen a stock shelf array collapse because the topmost shelf was overloaded and collapsed you would understand completely.