This Arduino compatible YF-S201 Hall-Effect Water Flow Sensor is used to measure the rate of flow of liquids. This sensor is attached in your waterline and it has pinwheel sensor to measure how much liquid has moved through it. The hall effect sensor is sealed from the water pipe and allows the sensor to stay safe and dry.

The YF-S201 Hall-Effect Water Flow Sensor comes with three wires: red (5-24VDC power), black (ground) and yellow (Hall effect pulse output). By counting the pulses from the sensor, you can easily sense liquid flow through the sensor.

Flowmeter with G1/2 Threads - simple output to measure the flow rate of water or other non-flammable liquids. Great for use with Arduinos or other microcontrollers - may also be used for gases with some adjustment for density. 1/2" Pipe Threads, Hall Effect Sensor interface, 1-30L/min 1.2MPa Capacity.

Sample code for Arduino:

/*
YF-S201 Hall Effect Water Flow Meter / Sensor
Read Water Flow Meter and output reading in litres/hour
*/

volatile int flow_frequency; // Measures flow meter pulses
unsigned int l_hour; // Calculated litres/hour
unsigned char flowmeter = 2; // Flow Meter Pin number
unsigned long currentTime;
unsigned long cloopTime;

void flow () { // Interrupt function
flow_frequency++;
}

void setup() {
pinMode(flowmeter, INPUT);
Serial.begin(9600);
attachInterrupt(0, flow, RISING); // Setup Interrupt
// see http://arduino.cc/en/Reference/attachInterrupt
sei(); // Enable interrupts
currentTime = millis();
cloopTime = currentTime;
}

void loop () {
currentTime = millis();

// Every second, calculate and print litres/hour
if(currentTime >= (cloopTime + 1000)) {
cloopTime = currentTime; // Updates cloopTime
// Pulse frequency (Hz) = 7.5Q, Q is flow rate in L/min. (Results in +/- 3% range)
l_hour = (flow_frequency * 60 / 7.5); // (Pulse frequency x 60 min) / 7.5Q = flow rate in L/hour
flow_frequency = 0; // Reset Counter
Serial.print(l_hour, DEC); // Print litres/hour
Serial.println(" L/hour");
}
}