Cheap Low Flow Meter

erk · Nov 14, 2017

I was looking for a low flow meter similar to the Neptune FS25 flow meter but that I could integrate into my DIY Raspberry Pi/Arduino controller. I came upon the following posted below. I bought three. Current plan is to use one with a calcium reactor I am designing.

https://www.amazon.com/gp/product/B...title_huc_1?ie=UTF8&psc=1&smid=A10ZX1GHP13ZSF

I will say, this flow meter is suspiciously similar to the Neptune FS25 flow meter. If I can find a datasheet, I will post the link here.

sneub · Nov 14, 2017

Following

erk · Nov 14, 2017

I wasn't able to find a datasheet. The company is a Chinese company with no website. All the data for their flow meters is shown directly on the purchase page.

Ranjib · Nov 15, 2017

For low precision work this is fine: https://www.adafruit.com/product/828

erk · Nov 15, 2017

Ranjib said:
For low precision work this is fine: https://www.adafruit.com/product/828

I was looking at those, but I didn't like the connections or that it didn't go lower than 1L/min. That translates to about 15 gph which is far greater than what is typically run thru a calcium reactor.

erk · Nov 16, 2017

I received the flow meters and took one apart. They are far smaller than I thought. Operate via hall sensor. Nothing crazy, but figured I would post the internals for anyone interested.

cilyjr · Nov 17, 2017

The neptune fs25 says it will only handle 3 to 12 gph. Which is about 190 ml per min. I was thinking of using it to keep tabs on my ca reactor effluent but that's too high. Bad move on neptune systems imo.

The one you linked claims .03-10 l/min (30-1000 ml/min) this would work for my needs!
Now to tie it into my apex...

Times like this is when I wish I went arduino

erk · Nov 17, 2017

You might be able to tie it into your Apex. Buy one of those 3 section audio jacks and solder the wires, granted you will need to know which pin is power, ground, and sense. That can be done with a multimeter though. The real issue I see is getting the K-factor into the Apex so you get a correct flow rate measurement.

cilyjr · Nov 17, 2017

Might be worth a post Christmas project for me. I would still need to buy an FFM for the Apex which I chose not to because I couldn't get what I really wanted out of it which was to monitor calcium reactor flow

doughboy · Nov 17, 2017

is the metal part going to touch saltwater?

erk · Nov 17, 2017

doughboy said:
is the metal part going to touch saltwater?

Yes. I imagine it is stainless steel. I don't think it will cause any issues though. Even if it rusts a bit, that is just extra iron in the tank. Since I have three, I will fill one with saltwater and leave it for a week. I'll post the results next weekend.

cypho · Nov 27, 2017

I have a bunch of similar flowmeaters on my tank. Some have been in use for over 2 years. I have used a bunch of different brands and they have all worked similarly.

The metal parts have not rusted on any of them. But the magnet does rust a bit on all of them. I have not noticed any ill effects from the magnet rust. But they require a good cleaning periodically (once or twice a year) to keep the rust from stopping the turbine.

I am using the exact one you posted on my RO filter and it has no problem accurately reporting the flow on the clean water and that is super slow. I actually have 3 of them on my RO filter (tap water in, waste out, clean out) and they are accurate enough that clean+waste is usually very close to tap water in. Should work well on your reactor.

cilyjr · Dec 3, 2017

@erk do you have a link to the arduino code to run this? (This might be beyond me) I'm thinking rather than spending big bucks tying it into the apex, it might be easier to buy a board and lcd display. I don't need to see it online or anything. But a simple display with ml/min near my reactor would be helpful!

Ranjib · Dec 3, 2017

I am planning to add support for these flow meters support in reef-pi as well. I was kinda take aback by their volume limit though. I have never used apex , so don’t know if they support higher volume flow meter or not. Would really love to measure flow in my return

cilyjr · Dec 3, 2017

The apex is for higher volume only. I have no idea why they would not have made a unit that would to do low flow. Something in the range of 20 to 200 ml/m. I think that would cover most calcium reactor flow. The lowest of the Apex can do is about 3 gallons per hour which is roughly 190 ml/m

erk · Dec 3, 2017

cilyjr said:
@erk do you have a link to the arduino code to run this? (This might be beyond me) I'm thinking rather than spending big bucks tying it into the apex, it might be easier to buy a board and lcd display. I don't need to see it online or anything. But a simple display with ml/min near my reactor would be helpful!

I don't have any code written yet, but what you want to use is the arduino's ability to frequency count. Below is the link to the Adafruit page where they sell a flow meter. They have a simple sketch you can use to test the flow meter and this sketch should work equally as well for us. Just make sure to replace the k-factor of the Adafruit flow meter with the k-factor for these.

cilyjr · Dec 4, 2017

This is where a friend of mine comes in. I'll show him this and the list of stuff I'll need to buy. I'm completely clueless to this as of now and will need to do some reading before I get started.

cilyjr · Dec 4, 2017

Not sure if this link will work but here's a list of supplies I think I need to make this but again I might be completely wrong.

https://www.amazon.com/hz/wishlist/ls/32VMUCA18T67Z

erk · Dec 4, 2017

cilyjr said:
Not sure if this link will work but here's a list of supplies I think I need to make this but again I might be completely wrong.

https://www.amazon.com/hz/wishlist/ls/32VMUCA18T67Z

That is the base of what you need. If you want to have a menu with buttons, you might consider the 16x2 LCD with buttons. The 16x2 LCD is incredibly easy to program. The touch screens are a bit more advanced, but straightforward once you get the code setup.