Reliable precision vacation automatic dog feeder and waterer 2

With a little time, my feeder has improved a great deal. I found out by accident that corrugated cardboard box can be treated like wood. You can screw them, bolt them and nut them, glue them, tie them, and best of all, they comes in with most mail orders over the Internet.

Now the feeder is almost like my original simple vision. Find or make a box that is large enough to hold one meal. Use the side with the smallest dimension as the door. Drill two hold to mount the motor, using small bolts and nuts. My toy motor kit comes with a gear box that can mount a rotating arm. The arm is used to keep the door shut. When the motor rotates, the arm rotates away and opens the door for the dry food to drop down. You can drop down a tray of wet food too.

The rest you need is a 7 day timer to turn on the dc adaptor, which in turn drives the motor for a minute. For each day (or meal) you need three components, box with motor, dc adaptor and timer. They work independently so it's highly reliable. There's no single point of failure. And unlike commercial ones that uses a single "valve" to move the dog food, my design allows you to put whatever you want into the box precisely - medicine, treats for different days of the week.

I mount the boxes near the top of a large cardboard box, and tie the large box to garden furniture. There is no mess as the food will not drop outside of the large box, and the dog can't possibly move the box tied to something heavy.

There are plenty of automatic waterers, basically like the toilet tank that will automatically fill themselves and shut off when full. But the commercial ones are far too small, and far too expensive compared to the toilet flush valve.

I was looking to build something to mount a small float valve when I found something better. It was a float valve designed for cattle. I just mount it on a bucket with the supplied hardware and attach a garden hose to it. The large volume in the bucket acts as a large dead weight so I don't need to fix it to anything. Even if the water supply is cut off, the bucketful can last for days.

Now it may be getting even better and more interesting. I'm going to build a reliable circuit so I can get rid of the adapters and the timers. There will only be one power supply, which can be AC indoors, DC outdoors or battery operated. Before that it's a bit daunting to set up all the timers and adapters and boxes.

Nowadays it's amazing with the net. You get electronic components from 1 to 1 million over the Internet, and you are welcomed the same. And there's the online datasheets for you to design like a pro. There are free circuit design software for you to download so you will be biased to a supplier's components. Then some other free software will turn your design into state of the art circuit boards. It's a little expensive to make a single product. But if you make a few to give it to family and friends, the cost isn't that bad.

Inevitably, I can't rely on cardboard boxes. They have to be replaced all the time. Again thanks to the Internet, you can use any materials you desire, from carbon fiber to metals to plastics. You just draw your parts on a free CAD package, push a button, and the price will be quoted to you. For my case acrylic is suitable. I can cut and glue it myself or I can find laser machines to cut the pieces for me with high precision.

If I go through with these, someday I may get rid of the bucket and turn the automatic waterer into a sculptured acrylic fountain.

Vacation automatic dog feeder for large breeds

The background is that I have just two days to find an automatic feeder so I can escape for a few days. Feeders are too expensive or not good enough to be sold in stores, so you can return easily. I couldn't find one and couldn't wait for mail order, so I have to build one. I don't even have time to wait for mail order components. And since I have no time to test the feeder, it must be very reliable.

For the first draft I can think of timer and sprinkler valves. For off the shelf components, I have to use one timer per day to activate something. Water is a good counter weight to bring food down from somewhere. Tubes can be custom made easily. Now sprinkler timers have 7 day program and each has at least alternate day programs. So I can save half the number of timers. I wasn't expecting too much of a vacation, just a weekend get away or up to a week will be good enough. It turn out that one timer per two days isn't a reality and so many custom pipes become a nightmare.

Then came the thought of a toy car coming out from somewhere to bring the food. A car each day. But now cars all come with remote control, so I have to rip off the remote control to get to the electronics, which adds to another level of unreliability. And also, the battery saving features in the cars may do something unexpected.

Fry's save the day. Now instead of an Outpost website, they put their name on it. I found toy motors online and found it in their stores too. Motors are everywhere, but theirs are kits, complete with gears box and mounting screws. Surprisingly it's purely made in Japan, and I don't know how they justify the low tech manufacturing, though the plastic gears are rather precise.

At the end, it become something like this, for each day:

• One AC 7 day timer - reliable and easy to program, you can't go wrong
• One AC to DC adaptor - to get 3 V for battery operated motor. With the exchangeable plugs, the motor wires can be clipped to the plugs without soldering.
• One motor with low gear ratio and mounted wheel.
• One heavy plank wood beam 1" x 2" in cross section
• A tray large enough for one portion of dog food
• Sewing thread to pull the tray
• A table in the yard
• Optionally a large bowl to receive the dog food

The motor is mounted at the end of the wood beam, which overhangs on the table. When the motor is on, it will coil the sewing thread and pull the tray of food. The tray is initially at the edge of the table, next to the beam as a sliding guide. Pulled by the motor at the end of the overhanging beam, the tray will fall off the table, and the food will fall down onto the ground or a huge bowl. Food pellets will fall everywhere due to the inaccurate trajectory of the tray. So you need a huge bowl to receive it or let it fall on the ground. You can also wrap the dog food in a bag if the bag is eatable or the dog will not eat it, you get the idea.

The gear ratio has to be low enough that the motor is powerful enough to overcome friction, and powerful enough to pull the thread to breaking point after the dog food is delivered to the ground. Since the thread is attached to the wheel and to the tray, the string thread has to break or it will be chaos. The mounted wheel isn't important as long as the thread has something to tie to. The powerful motor will ensure that the thread will coil up somewhere and pull the tray along the beam.

The beauty of it is the reliability. If anything fails the dog just miss one meal. Unlike the other feeders, the dog will starve for a week and die.

I have been thinking of improving it so it can be used daily to save labor. However, you need something like a grain screw as in the commercial feeders. If I can find something like that, I can attach it to an electric drill, which could be rather reliable. Though the amount of dog food delivered will not be exact.

There are also other toy motor kids that allow you to build a conveyor belt for example. You might be able to build a single feeding machine instead of 7 machine if you leave for a week. For reliability, you can use two machines, one for the even and one for the odd days.