OPEN-SMART G3/4 Chrome-plated Alloy Steel Water Flow Sensor Turbine Hall Flowmeter for Arduino

It is turbine type water flow measuring sensor. When water flows through it, it will output a number of pulses. By counting the pulses from the output of the sensor, you can easily calculate water flow. Each pulse is approximately 3.33 milliliters.
We have as example Arduino sketch that can be used to quickly test the sensor, it will calculate the approximate flow of water in liters/hour.
The pulse signal is a simple square wave so its quite easy to log and convert into liters per minute using the following formula.
Pulse frequency (Hz) = 6.6 * flow rate in L/min.   
Features:
- Measurement flow range: 1 ~ 30 L/min
- Working voltage: 4.7~15 VDC
- Working current: ¡Ü 10 mA (DC 5V)
- Working humidity: 35%~90%RH (no frost)
- Working pressure: < 1.75Mpa
- Working temperature: -25 ~ +80 ¡æ
- External thread: G3/4 (3/4 inch)
- Output connector: 2.54MM-3P
- Output leads: yellow (DATA), red (VCC), black (GND)
- Lead length: 30cm
- Application: water heaters, credit card machines, water vending machine, water flow measurement device