FLUXO.INO

🚰 Arduino Water Flow Watchdog

(protection against water leaks)

• HAL Water Flowmeter Sensor + Solenoid Flow Valve + Home Assistant (MQTT)
• Optimized for Arduino Nano R3 (ATmega328P) and Ethernet module ECN28J60

I made this project after have some leakages and being caught by a very expensive water bill! 🧾 💸 The goal is not only creates a Arduino water flow sensor, but a small "robot" that can close the water flow autonomously (if required) case detect any water leakages (i.e., "leakage watchdog").

Features:

• home assistant water flow sensor
• home assistant water flow switch (solenoid water valve) (optional, see config flags)
• home assistant leakage probability sensor (percentage)
• autonomously closes the water flow case detect water leakages, i.e., "leakage watchdog" (optional, see config flags)
• displays water flow information on 16 x 2 LCD (optional, see config flags)

Source code:

• https://github.com/fortalbrz/fluxoino/
• arduino nano sketch
• wiring testing sketch

REMARKS

• Arduino Nano with the CH340g USB/serial transceiver requires the Windows driver (next section)
• this sketch should be pushed with Arduino IDE using configuration:
  • Board "Arduino Nano"
  • Processor: "ATmega328P (Old Bootloader)".
• sets the macro "DEBUG_MODE true" in order to use serial communication for debugging (i.e., "Serial Monitor", see config flags)

Drivers (CH340g) for Arduino Nano:

• CH340g USB/Serial driver (windows 11 compatible driver)
• driver install instructions (pt-BR)

Configuration flags

Use these configurations flags to set fluxoino behaviour (as you wish). You can avoid dispensable hardware and features to fit your needs...

macro	default	description
RELAY_SIZE	8	number of relays (valid: 1 to 8)
USE_LCD_DISPLAY	true	enables/disables LCD display (disable it if not in use the LCD display)
USE_HOME_ASSISTANT	true	enables/disables Home Assistant integration (MQTT) (disable it if not in use the LAN network module)
USE_WALTER_FLOW_VALVE	true	enables/disables water flow valve (disable it if not in use the solenoid valve)
CAN_CLOSE_WATER_FLOW	false	enables/disables autonomous water valve closing (relaying on LEAKAGE_THRESHOLD)
MQTT_BROKER_ADDRESS	ip	MQTT broker IP address (e.g., mosquitto broker), (requires USE_HOME_ASSISTANT true)
LEAKAGE_THRESHOLD	0.9	leakage detection sensitivity - threshold as percentage of the maximum theoretical flow (in range: 0 to 1)
LEAKAGE_INTEGRATION_WINDOW_SECONDS	600	sample window for flow volume integration (leakage volume estimation parameter) (default: 600 = 10 min)
LAMBDA_EWMA	0.98	lambda EWMA (moving average weight of water flow measurement) (in range: 0 to 1)
PULSES_PER_LITER	450	pulses per liter (from HAL flowmeter sensor datasheet)
DEBUG_MODE	false	true for serial debug (home assistant disabled), false for production (home assistant enabled)

Remark: home assistant can be disabled and therefore fluxoino will only work as standalone flowmeter (LCD display) and/or solenoid valve valve (leakage watchdog)

Materials:

• Arduino Nano R3 (ATmega328P)
• Ethernet LAN Network Module (ENC28J60) (optional, only with home assistant, see config flags)
• water flow sensor G 1/2"
• solenoid valve 3/4" 12v (normally opened) (optional, see config flags)
• power supply 12vdc (2A)
• 1 x rotary potentiometer 10k Ohm (Linear) (optional, only with LCD display, see config flags)
• 1 x N-channel MOSFET 60V 30A (TNMOSFETFQP) (optional, only with solenoid valve, see config flags)
• 1 x voltage regulator 3.3v (LD11173v3) (optional, only with solenoid valve, see config flags)
• 1 x diode rectifier 1A 50V (optional, only with solenoid valve, see config flags)
• 2 x 10K Ohm Resistor (optional, only with solenoid valve, see config flags)
• 1 x electrolytic decoupling capacitor 10uF/25V (optional, only with solenoid valve, see config flags)
• 1 x capacitor ceramic 100nF (optional, only with solenoid valve, see config flags)

Circuit Wiring Instructions:

• circuito.io - step by step

Wiring

• diode 1A 50V (positive) --> power supply 12vdc (positive/Vcc)
• Arduino Nano pin29 (GND) --> power supply 12vdc (negative/Gnd)
• Arduino Nano pin30 (VIN) --> diode 1A 50V (negative)
• solenoid valve coil 1 --> diode 1A 50V (positive)
• solenoid valve coil 2 --> diode 1A 50V (negative)
• diode 1A 50V (positive) --> TNMOSFETFQP Drain (center)
• water flow sensor VCC (red/center) --> 5v (Arduino Nano Pin29)
• water flow sensor GND (black/left) --> Gnd (Arduino Nano Pin29)
• water flow sensor SIG (yellow/right) --> 10K Ohm Resistor A (terminal 1)
• 10K Ohm Resistor A (terminal 1) --> Arduino Nano pin5 (D2)
• 10K Ohm Resistor A (terminal 2) --> 5v (Arduino Nano Pin29)
• TNMOSFETFQP Gate (left) --> 10K Ohm Resistor B (terminal 1)
• TNMOSFETFQP Gate (left) --> Arduino Nano pin7 (D4)
• TNMOSFETFQP Source (right) --> Gnd (Arduino Nano Pin29)
• voltage regulator LD11173v3 Vin (right) --> 5v (Arduino Nano Pin29)
• voltage regulator LD11173v3 Gnd (left) --> Gnd (Arduino Nano Pin29)
• voltage regulator LD11173v3 Vout (center) --> 10uF electrolytic capacitor (positive)
• voltage regulator LD11173v3 Vout (center) --> ethernet module ENC28J60 Pin9 (VCC)
• 10uF electrolytic capacitor (positive) --> Gnd (Arduino Nano Pin29)
• 100nF ceramic capacitor --> between Vcc and Gnd
• LCD Pin2 (VDD) --> 5v (Arduino Pin27)
• LCD Pin15 (A) --> 5v
• LCD Pin1 (VSS) --> Gnd (Arduino Pin29)
• LCD Pin5 (RW) --> Gnd
• LCD Pin16 (K) --> Gnd
• LCD Pin4 (RS) --> Arduino Nano Pin19 (A0)
• LCD Pin6 (E) --> Arduino Nano Pin12 (D9)
• LCD Pin11 (D4) --> Arduino Nano Pin8 (D5)
• LCD Pin12 (D5) --> Arduino Nano Pin9 (D6)
• LCD Pin13 (D6) --> Arduino Nano Pin10 (D7)
• LCD Pin14 (D7) --> Arduino Nano Pin11 (D8)
• LCD Pin3 (VO) --> 10k ohm potentiometer middle pin (the other two pins go to 5v and Gnd)
• ethernet module ENC28J60 Pin2 (INT) --> Arduino Nano Pin6 (D3)
• ethernet module ENC28J60 Pin4 (SO) --> Arduino Nano Pin15 (D12)
• ethernet module ENC28J60 Pin5 (S1) --> Arduino Nano Pin14 (D11)
• ethernet module ENC28J60 Pin6 (SCK) --> Arduino Nano Pin16 (D13)
• ethernet module ENC28J60 Pin7 (CS) --> Arduino Nano Pin13 (D10)
• ethernet module ENC28J60 Pin10 (GND) --> Gnd (Arduino Nano Pin29)

Home Assistant

The solution will be discoverable as MQTT device with:

MQTT sensors

Name	uid	description
Flow Sensor	sensor.flow_sensor	water flow (L/min)
Leakage Prob	sensor.leakage_prob_sensor	leakage detection probability
Flow Switch	switch.flow_switch	water valve switch (on/off)
Flow Reset	button.flow_reset	reset EWMA flow estimation

Futhermore

Exponential weighted moving average (EWMA) flow estimation:

  flowEWMA[t] = lambda * flow[t] + (1 - lambda) * flowEWMA[t-1]

where:

 flow[t] =        pulses_in_1_sec * 60 / PULSES_PER_LITER          [liters/min]

 flow[t] = 0.06 * pulses_in_1_sec * 60 / PULSES_PER_LITER          [m3/h]

Jorge Albuquerque (2022)

References:

• HAL flowmeter sensor
• solenoid valve circuit connection
• lcd display