by mtcboom
Float switches?
2:49 pm in electronic components, Materials and Resources, questions, Seeking Advice by mtcboom
Has anyone experimented with a float switch as a way or triggering a pump instead of using a timer? A friend suggested this to me and it looks like the switches are really cheap compared to timers. The idea is like the float in a toilet tank, but instead of turning off the water when the resevoir reaches a certain level, a circuit closes inside the switch when water reaches a level and turns power to pump on or off. Here’s an example of what I’m talking about:
http://www.aquahub.com/store/ifloatfloatswitch.html
Kind of a late reply…but I was hoping discussion on this would start up. I wish to build a window farm, but the whole air pump system seems wasteful. It is very inefficient and it is on all the time. I have worked in the medical field for many years and it would seem to me that the most accurate way to measure fluid fall into the containers would be to start an IV drip. For this to happen you would have to have a gravity fed system with the fluid above the plants. The way to get that fluid up there is with a pump.
So…Amazon sells this fountain pump which is very small, yet can pump fluid 8 feet into the air:
http://www.amazon.com/Sunterra-137016-Extra-Large-Fountain/dp/B0002HFTIY/ref=sr_1_5?ie=UTF8&qid=1287567901&sr=8-5
As the fluid falls back down, it could collect into a food grade container where the pump sits. This kit can be used to measure the levels of fluid in the reservoir:
http://www.aquahub.com/store/media/TopitOffKitDeluxeInstruxCompDec07.pdf
If the falls to a certain level the pump will turn on. If it falls too low, it will shut down the pump so that it doesn’t run dry. Total cost would be less than $100 and it would not constantly run. The power draw would be less, and using IV tubing to deliver the fluid would allow you to do be accurate down to a fraction of a milliliter.
Has anyone tried this?
I let my windowfarm v1.0 go idle over the summer so your timing is good – I’m just beginning to think about getting a v2.0 going now as the regular garden season winds down. I’m really interested in your IV drip idea. Just to be clear, with an airlift pump it’s not on all the time, rather is on for a few minutes at a time on intervals set with a timer.
The fountain pump you found looks good, but may be too big to fit inside 4″ PVC tube which I’m currently using for bottom resevoir. I’d love to switch to different materials for the resevoirs. What do you have in mind as a “food grade container?” Last year I just built my first system according to the windowfarms plans at the time, but this year I hope to switch to something other than PVC.
Eh…
Who said that the airlift pump needs to run all the time?
Mine runs for 15minutes/hour during the day(except for on the warmest of days, when I may add a 15minute period in between those on the hotter parts of the day) and 15minutes/2hours during the night.
With a typical pump running at 6W(for up to 4 columns, the 2outlet pump I used in the beginning drew 3W), that doesn’t cost all that much during a year…
Gravity feed has been tried, and I belive it has mostly been abandones because of clogging in the drips. Also, there’s the noise problem.
This pump is a 21W ‘impeller type’ pump, and at 7′ it’s listed as 60Gallon/Hour. 8′ is listed as ’0′ in the manufacturer’s instructions.
http://www.sunterrausa.com/uploads/qg/ox/qgoxVfbxOvNumralcyGYHg/Fountain-Pumps.pdf
They also state that it’s NOT for ‘dirty water’…
But if you can make it work for you, go ahead.
Water Level Switch
I am working with the float switch you are interested in.
I get mine here:
http://www.seeedstudio.com/depot/water-level-switch-p-565.html?cPath=119_121
Using a arduino to get to function is a lot of work. I am real close to getting it to perform in a test system. I have been blogging about my progress at this site:
http://www.rik94566.wordpress.com
Once I get the code and arduino working correctly I will be doing an instructable about it.
You will need a relay to turn the water pump on and off depending on the float switch values. Here is a good one and is easy to use.
http://www.seeedstudio.com/depot/electronic-brick-5v-relay-module-digital-p-479.html?cPath=48_53
If interested in my progress you can email me off line.