G1/2 Hall Effect Water Flow Sensor – 1–30 L/min

The G1/2 Hall Effect Water Flow Sensor is designed to measure the flow rate and quantity of water passing through a pipe or liquid system. It combines a plastic valve body, internal water rotor, magnet, and Hall-effect sensor to generate electrical pulses proportional to the water flow.

As water passes through the sensor, it rotates the internal impeller. The Hall-effect sensor detects this rotation and generates a pulse signal that can be counted by a microcontroller to calculate the approximate flow rate and total volume of water.

It is suitable for Arduino projects, water dispensers, coffee machines, water-control systems, irrigation projects, water heaters, and automated liquid-monitoring applications.

Technical Specifications

• Sensor Type: Hall Effect Water Flow Sensor
• Connection Size: G1/2"
• Flow Rate Range: 1–30 L/min
• Minimum Working Voltage: 4.5 V DC
• Working Voltage: 5–24 V DC
• Maximum Working Current: 15 mA at 5 V DC
• Output: Hall-Effect Pulse Signal
• Output Load Capacity: ≤10 mA at 5 V DC
• Operating Temperature: ≤80°C
• Maximum Liquid Temperature: ≤120°C
• Operating Humidity: 35–90% RH
• Maximum Water Pressure: ≤1.75 MPa
• Storage Temperature: -25°C to +80°C
• Storage Humidity: 25–95% RH
• Body Type: Plastic
• Installation: Inline
• Suitable For: Water Flow Measurement & Monitoring

How It Works

Inside the sensor is a small water rotor fitted with a magnet.

When water passes through the sensor, the rotor begins to rotate. As the magnet passes the Hall-effect sensor, an electrical pulse is generated.

The faster the water flows, the faster the rotor rotates and the higher the pulse frequency becomes.

A microcontroller can count these pulses to estimate:

• Instantaneous Flow Rate
• Total Water Volume
• Water Consumption
• Flow / No-Flow Status

3-Wire Interface

These Hall-effect water flow sensors commonly use three wires:

• Red – Positive Supply
• Black – Ground
• Yellow – Pulse Signal Output

The pulse output can be connected to a suitable digital input or interrupt-capable GPIO on a microcontroller.

Always verify the wire colors on the actual sensor before connection, as cable arrangements can vary between manufacturers.

Arduino & Microcontroller Compatibility

The sensor can be integrated with controllers such as:

• Arduino Uno
• Arduino Mega
• Arduino Nano
• ESP32
• STM32
• Raspberry Pi Pico
• PIC
• AVR

The controller measures the frequency of the Hall-effect pulses and converts this information into an estimated flow rate using the calibration factor for the specific sensor.

Flow Rate Measurement

The sensor provides a pulse frequency that changes according to the amount of water flowing through it.

By measuring the pulse frequency over a known period, software can calculate the approximate water flow in liters per minute (L/min).

The pulses can also be accumulated over time to estimate the total volume of water that has passed through the sensor.

For applications where accuracy is important, the sensor should be calibrated against a known volume or reference flow meter because the actual pulse-to-flow relationship can vary between sensor models and installations.

Compact & Easy to Install

The inline threaded design makes the sensor convenient for integration into water systems.

Typical uses include:

• Water Dispensers
• Coffee Machines
• Water Heaters
• Irrigation Systems
• Automatic Watering Systems
• Water Vending Machines
• Liquid Dispensing Projects
• Water Consumption Monitoring
• Smart Home Projects
• IoT Water Monitoring

Important Note

The 1–30 L/min range is a nominal operating range. Measurement accuracy can be affected by water pressure, turbulence, installation orientation, pipe configuration, temperature, and individual sensor variation.

For accurate volume measurements, perform a practical calibration after installation.

The maximum pressure and temperature ratings should not automatically be interpreted as suitable for every high-temperature or pressurized plumbing installation. Hose, fittings, seals, and the complete installation must also be rated for the intended conditions.

When interfacing the pulse output with a 3.3 V microcontroller such as an ESP32, verify the actual output circuit and voltage level of the supplied sensor before connecting it directly to a GPIO pin.

Applications

Ideal for water-flow measurement, Arduino projects, ESP32 monitoring systems, coffee machines, water dispensers, irrigation systems, automatic watering, water heaters, liquid dispensing, smart-home systems, IoT monitoring, laboratory projects, educational electronics, and DIY water-management systems.

Package Includes

1 × G1/2 Hall Effect Water Flow Sensor