Water Flow Meter / Sensor- RPi 20 - YF-S201 Hall Effect

[tsbrownie]

An intelligent water meter that can be used to control multiple functions (valves, detectors, warnings, logging...).

An RPi experiment using the YF-S201 flow meter. Good for measuring and controlling water flows - home watering use, irrigation water use tracking, livestock water tanks, etc.

Line 37: print('Time (min & clock) ', minutes, '\t', time.asctime(time.localtime(time.time())),'\n')

The sensor is inline and uses an impeller with an embedded magnet. The magnet triggers a Hall effect switch sending a pulse at each revolution.
There are 3 wires, red (power, 2-24 volts, but I've gotten it to work at 3 volts), black (ground) and yellow (Hall effect output).
From the spec sheet:
16 Hz = 2 L/min = 120 L/hr
32.5 Hz = 4 L/min = 240 L/hr
49.3 Hz = 6 L/min = 360 L/hr
65.5 Hz = 8 L/min = 480 L/hr
82 Hz = 10 L/min = 600 L/hr
etc. Max 30 L/min
Frequency (Hz) = 7.5 * Flow rate (L/min)
Pulses per Liter: 450

Model: YF-S201
Sensor Type: Hall effect
Working Voltage: 3.5 to 24V DC (min tested voltage 3.3V)
Max current draw: 15mA @ 5volts
Output Type: 5volt TTL
Working Flow Rate: 1 to 30 Liters/Minute
Accuracy: ±10%
Maximum water pressure: 2.0 MPa
Operating Temperature: ≤80℃
Liquid Temperature: ≤120℃
Output duty cycle: 50% ±10%
Output rise time: 0.04us
Output fall time: 0.18us
Min Durability: 300,000 cycles
Cable length: 15cm
1/2" nominal pipe connections, 0.78" outer diameter, 1/2" of thread
Size: 2.5" x 1.4" x 1.4"

Notes: I found that when the impeller stops with the Hall effect switch triggered, it keeps sending pules to the RPi. Seems to be a Pi triggering issue per the internet.
YOU NEED A VOLTAGE DIVIDER WHEN OPERATING ABOVE 3.3 VOLTS!!!

MATERIALS
- Raspberry Pi (and Pi power supply)
- Breadboard
- YF-S201 Water meter / sensor
- Jumpers

WARNING: Warning: mis-wiring or mis-programming your Pi or miswiring of accessories can ruin the Pi and accessories.
Information/drawings offered as is. Use at your own risk. If you don't know, learn first.