Has anyone done any work on reading a flowmeter with an Arduino, PIC, etc? I'm assuming it's some kind or analogue pulse that would need to be read, so would I need to feed the flowmeter into a comparator before the Arduino?

Any help would be appreciated.

Whoops; I did a search first and came up with nothing, but straight after I found this

Gicar flowmeter signal

This looks like I could use PulseIn() as described at http://arduino.cc/en/Reference/PulseIn

I would still like to hear from anyone else who has already done this.

hello,

I never finished the home made flow meter electronics, and as my machine gets turned on and off every day it would loose the settings anyway, so I wasn't too motivated.

as I understand it you want to connect an off the shelf flow meter to a home-brew controller.

if you want to use this flow-meter you'd have to get the voltages right for a PIC or similar, ie. 5 v or less
as the standard flow meters work on 18v or thereabouts, you might have to put in a reed switch or similar to switch a lower voltage supply. or do something with resistors to lower the voltage.

I do still think that the flow-meter sinks the voltage from the controller, but as I never got to the bottom of this I cannot say for sure.

Hope this helps.

Well as a first step, I think I'll set up a test bed with a pump and a flowmeter and put a scope on the flowmeter and see what I get.

If you are just trying to get a standard flow meter to work with a Arduino I think I can help. I have attached a circuit that is used by both Digmesa and Gicar. Essentially there is just a hall effect sensor close to the impeller blade inside the meter. The impeller has he magnets on it. Every time a magnet passes the Hall Effect Sensor it closes.
If you place the corret resistor in the circuit (to limit the current to the micro) then you an use any of the rated voltage. Gicar uses the transformer voltage (usually 9 or 12V). If you want to see what it does on a scope I can probably take a little video.

EDIT: whoops here is the lin for the documentation
http://www.digmesa.com/digmesa/upload/p ... F01_GB.pdf

BIll C

Very nice thank you BillC.

Mark

Hi guys,

always thought it acts like a simple switch, but without the need to debounce it, so it should be fairly simple to count the 'ticks'. You can try (compare to a normal input) and hook it up to an interrupt pin, just make sure you don't do much in the interrupt itself, otherwise you might miss some edges.

Regards,
dsc.

Yeap, that's the way I'm going at the moment. I've just got the interrupt working on a pulse, wo I'll use the circuit BillC provided (thanks Bill) to link it up. Thank goodness the Arduino supports interrupts and hardware timers.

Just a suggestion, but a opto-isolator in there will prevent any strange voltages from crossing the two circuits. And since most isolator chips work open drain you can use a voltage on the downstream side that your micro controller is compatible with.

-Cecil