Sometimes off-the-shelf solutions to a problem don’t meet your expectations. That’s what led [TomGoff] to build his own solar pond fountain.
This build features a lot of creative reuse of materials [TomGoff] already had on hand, like the end of a cable reel for the platform and a wheelbarrow inner tube for flotation. A 3D printed nozzle in the center of this apparatus is attached to a 12 V water pump and the whole thing is controlled by an Arduino running 30 seconds on and 3 minutes off to conserve battery power.
A hand-built perfboard contains a light dependent resistor (LDR) to tell the Arduino not to run at night, the relay for the pump, and a battery charge monitor. Be sure to check out the full write-up to see the video of the Tinkercad electronics simulation as well as the code. A 20 W solar panel keeps the whole thing charged so you don’t have to run mains power out to your pond.
If you need more solar projects for your garden, how about this Charmander lamp or a solar powered irrigation system?
For real?
What kind of pump is that only sprinkling with a 20W solarpanel?
And 30s on/3min off?
If it’s a solar panel rated at 20W, it means it will get 20W in ideal condition (once a century when the moon is in the eighth house of Aquarius). Also, the 20W panel doesn’t power the pump directly.
Which leads me to my concern: if the point is to aerate the pond whilst using renewable energy, the whole control system (Arduino and battery) is completely unnecessary and if anything wastes energy that could be used to run the pump. Powering the pump directly from the solar panel would simplify the whole product tremendously, in particular regarding water ingress management. It wouldn’t make a good instructable + HaD article though, so I guess that was the goal #1 of the whole project.
Even if they only want the pump to run on that 3/30 during the day schedule, the battery and the LDR are extraneous. The solar panel already senses when there’s light or not.
Over-engineered. Good for him!
A battery is the straightforward way to run the pump consistently rather than only when there is enough sunlight to start it. The battery can also store excess. It’s not that expensive and driving the pump from the panel potentially wastes much more solar power.
My greenhouse is about 40 feet away from my pond and up about 15 feet by the time you get to the shelf height in the greenhouse. I have a pi zero w with a solar set up to make it mostly go and report the weather in there, as well as the door status, and at some point in time an A/D to monitor the panel and the battery.. I had pondered adding the pump to that but the solar watering system works 100% dependably being brain dead stupid. That is I have a good quality submersible 12V pump in a 5 gallon bucket that has lots of tiny holes drilled in it and 5 red bricks held around the inside bottom with stainless wire. The bucket has a lid with two holes in it, one for the hose to exit out of and one for the power leads to exit out of. The bucket keeps everything but fine silt out and the pump is more near the top than the bottom so it gets nice water. The pump is brainlessly powered by a 40W solar panel that is more or less propped up to peak out in the early afternoon. The water from the pump goes into a piece of 2″ pvc that is about 18″ tall with a wooden stopper at each end. Water goes in at the top, there is a bolt on the bottom you can take out to drain any sediment that makes it that far, and there are 6 little holes around the perimeter about 3/4 of the way up, small 1/8″ tubing fits in there and goes to the plant boxes. Flow rate is controlled by a combination of sticking baling wire in the tubing and raising the tubing up. Overall it works great, on very bright and sunny days the plants get so much water they piss, but they can do that freely, and no water once it is dark, and on not so nice days they get a small amount. Seems to work very well.
I had one friend who was worried about the pump as to be honest I have no idea how many volts it gets, I think something upwards of 19 on a super bright day, but it both being over powered and under powered, as in when it does not have enough power to move. I think the fact it is a sub pump and on the bottom of a large pond is the key. It has an almost infinite heat sink around it for the amount of power it takes, so I don’t think it gets too hot when it is sunny out, and given it is a sub pump, it is not like it is air cooled and the motor spinning is going to make it any cooler. It it was on the surface and air cooled and had fins so when the motor moved it moved air, I would totally agree, but that is not the case. It has been a bunch of years now and it is still kicking so it seems not to be killing pumps. BTW, I did get a good quality RV pump for this project. I think it was upwards of $50 when I got it. And I am just at the limit of what it is rated for as far as pushing water uphill. Lucky for me I did not want a lot of flow. Anyway, it works good sans any fancy electronics.
Is pumping air down into water would be better?
Aeration like in home aquarium.
* Checks code * Delay (180000) // wait for 3 mins to allow battery to charge * Facepalm *
So the code spins the Arduino at full tilt, making no attempt to save power for three minutes at a time, waiting for the battery to charge. Riiiiggghhttt.
If you’re the author, or someone copying this, I beseech you to look into “proper” Arduino Deep Sleep modes / libraries. It will definitely make a big improvement (potentially orders of magnitude) on the power side of things. e.g. https://docs.arduino.cc/learn/electronics/low-power/