I am using a Netafim M-Series flow meter interfaced with a UC-32 Arduino. The goal of this is to create a pulse counter than in turn will allow us to determine flow rate in the meter. (1 US gallon per pulse for this model.)

I am using a relatively simple program to test my wiring and the flow meter's connection to the UC-32. I will include it here:

int pin = 30;
volatile unsigned int pulse;
const int pulses_per_litre = 450;

void setup()

  pinMode(pin, INPUT);
  attachInterrupt(0, count_pulse, RISING);

void loop()
  pulse = 0;

  Serial.print("Pulses per second: ");

void count_pulse()

Code was obtained by a source online, since I will make my own to match my specific needs later on. The problem is, no matter how much I modify this code, I receive 0 pulses (even when blowing air into the meter). I have therefore narrowed down the problem to wiring.

I am using a small breadboard with a 1 kOhm Resistor. The flow meter requires 12v input that is supplied by a barrel jack power supply into the UC-32. I will show an image of my circuit. From what I can see, this should be working, but I feel like I'm sort of going insane looking over and over this circuit so I wanted to get an outside opinion.

Breadboard UC32

Sorry about the large sizes images, but to me, it is a simple circuit that should work. I could be very wrong. Does anyone with perhaps experience with this sort of flow meter see any problems with my code/circuit?

1 Answer 1


Fixed, wow. Sometimes typing out your problem helps answer the question. Resistor position was wrong, and adjusting the Vin wire.

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