Cheap pulse flow meter

ASF · Oct 17, 2016

Hi all,

On the hunt for a cheap pulse flow meter for a home automation project. Just needs to be 24VDC, somewhere around 20mm size, and somewhere in the range of 10 pulses per litre. It's just measuring water, nothing really unusual about the application.

Anyone got any hot tips?

Saffa · Oct 17, 2016

Jaycar used to do a hall effect flow sensor but i think it's been discontinued.

https://www.adafruit.com/product/828

Is similar. Accuracy isn't awesome, but if you have a reasonably constant pressure then it should be possible to calibrate the meter using the ol bucket and stop watch approach.

Tom Jenkins · Oct 17, 2016

Dwyer tends to have low cost sensors: https://www.dwyer-inst.com/

Doug-P · Oct 17, 2016

I dunno what 'cheap' means but, lots of residential water softeners now have flow sensors to trigger a regeneration cycle based on gallons used. Something like that might work.

g.mccormick · Oct 17, 2016

I keep wanting a reason to buy this one

https://www.amazon.com/gp/product/B00GM5DCCA/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A2TGPS3W9E2D5C

rootboy · Oct 17, 2016

Doug-P said:
I dunno what 'cheap' means ...

So here's cheap:

http://www.futurlec.com/Flow_Sensor.shtml

Just a word of advice, Futurlec has great prices on all sorts of electronics, but not a very good reputation on delivery.

mendonsy · Oct 17, 2016

Those flow meters are made by Savant in Taiwan. I suspect futurlec has to order them and wait for the boat to arrive. Might be worth the gamble at those prices.

rootboy · Oct 17, 2016

mendonsy said:
Those flow meters are made by Savant in Taiwan. I suspect futurlec has to order them and wait for the boat to arrive. Might be worth the gamble at those prices.

My first order from Futurlec came in without a hitch, the second one took like 3 - 6 months, I haven't been back since.

The secret is to never order anything that doesn't show up as "In Stock", since they will hold your order until those parts arrive.

ASF · Oct 17, 2016

Thanks guys. Accuracy isn't a huge factor, even if it's only +/- 20% it will do the job I need it for.

All of the links look good as far as price and size etc, but it looks like most of them are around 250 pulses per litre, which might be a little fast. It's just going to be wired into a standard digital input on a Click Koyo, so ideally I'm after more in the realm of 10-100 pulses per litre (or about 40-400 pulses per gallon, for the 'mericans

). Any tips?

rootboy · Oct 17, 2016

1) Go with a higher LPM meter than you strictly need (but not too high). Since it's going to go "slower" you won't be as likely to overrun your input.

2) Run you input into a divide by "x" circuit (I've used them expressly for this purpose). I wouldn't buy one, that flies in the face of cheap! And it's an easy enough circuit to make. But when I worked for Schneider, money was no object. Plus they wouldn't allow me to include my homebrew in the final products (short-sighted of them in my opinion).

shooter · Oct 21, 2016

check on arduino sensors, cheap

Cheap pulse flow meter

ASF

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Saffa

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Tom Jenkins

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Doug-P

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g.mccormick

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rootboy

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mendonsy

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rootboy

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ASF

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shooter

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