Rain/Raindrops Detection Sensor - Weather Humidity Module
Rain/Raindrops Detection Sensor - Weather Humidity Module
Rain/Raindrops Detection Sensor - Weather Humidity Module
Rain/Raindrops Detection Sensor - Weather Humidity Module
Rain/Raindrops Detection Sensor - Weather Humidity Module
Rain/Raindrops Detection Sensor - Weather Humidity Module

Rain/Raindrops Detection Sensor - Weather Humidity Module

Sensors
DET525
Part.No: FR-04
€3.25
In Stock
Immediate Dispatch
FR-04 Rain & Raindrop Detection Sensor Module with LM393 comparator, dual analog/digital output, and 3.3V–5V operating voltage. Compatible with Arduino, ESP32, and Raspberry Pi projects.

 

The FR-04 Rain/Raindrop Detection Sensor Module (MPN: FR-04) is a weather humidity sensing board designed to detect the presence of rain or moisture on its surface. It outputs both a digital on/off signal and an analog voltage, making it easy to integrate into automated irrigation systems, weather stations, and smart home projects. Operating between 3.3V and 5V, it is compatible with the full range of popular microcontroller platforms.

Key Features

  • High-Quality FR-04 Double-Sided Board (5.5 × 4.0 cm): Large sensing area with nickel-plated surface treatment → excellent oxidation resistance, superior conductivity, and long service life
  • Adjustable Sensitivity: On-board potentiometer for fine-tuning the detection threshold → adapts to different rain intensities or humidity levels
  • Dual Output — Digital (DO) & Analog (AO): Digital switch output (0/1) plus analog voltage output → works with both simple GPIO reads and ADC-based measurements
  • LM393 Wide-Voltage Comparator: Clean signal with strong driving ability (>15 mA) → reliable, noise-free switching even over longer wire runs
  • 3.3V – 5V Operating Range: Broad voltage compatibility → works with 5V Arduino boards and 3.3V ESP32/Raspberry Pi without level shifters
  • Mounting Holes: Fixed bolt holes on the PCB → easy and secure installation in enclosures or project cases

Pinout & Wiring

PINSymbolDescription
1VCCPower supply: 3.3V or 5V DC
2GNDGround
3DODigital output: HIGH (dry) / LOW (wet) — connect to any GPIO pin
4AOAnalog output: voltage proportional to moisture level — connect to an ADC pin

Wiring note: Connect VCC and GND to your board's power rails. Use DO for simple wet/dry detection with any digital GPIO. Use AO with an analog input (e.g., Arduino A0) for graduated moisture readings. Adjust the on-board potentiometer to set the sensitivity threshold for your environment.

Compatibility

  • Arduino UNO / Nano / Mega (5V): Plug-and-play — power from 5V, read DO on any digital pin and AO on any analog pin.
  • ESP32 / ESP8266 (3.3V): Power from 3.3V; use DO on GPIO and AO on ADC-capable pin. No level shifter required.
  • Raspberry Pi (3.3V): Use DO on GPIO for digital detection. For AO, an external ADC (e.g., MCP3008) is needed since Raspberry Pi has no built-in ADC.

Typical Applications

  • Automatic rain alerts: Trigger a notification or close a window when rain is detected on your Arduino or ESP32 home automation system.
  • Smart irrigation systems: Prevent watering during rainfall by pausing your pump when the sensor detects moisture.
  • Weather stations: Log rain events as part of a DIY environmental monitoring setup with Raspberry Pi or ESP32.
  • Automotive / greenhouse automation: Activate wipers, close vents, or raise greenhouse covers automatically when rain begins.
  • Robotics: Add weather-awareness to outdoor robots so they can seek shelter when it starts raining.

Technical Specifications

ParameterValue
InterfaceDigital (DO) + Analog (AO)
Operating Voltage3.3V – 5V DC
Output Drive Current> 15 mA
Comparator ICLM393
Sensing Board MaterialFR-04 double-sided, nickel-plated
Sensing Board Dimensions55 × 40 mm
Sensitivity AdjustmentOn-board potentiometer
MPNFR-04

FAQ

Q: Do I need a level shifter to use this with an ESP32 (3.3V)?
A: No. The module operates from 3.3V, so you can power it directly from the ESP32's 3.3V rail and read DO/AO without any additional components.

Q: What does the potentiometer do?
A: It adjusts the comparator threshold on the LM393. Turning it changes the moisture level at which the DO pin switches from HIGH to LOW, allowing you to fine-tune sensitivity for light drizzle versus heavy rain.

Package Contents: 1× FR-04 Rain Detection Sensor PCB (with control board and sensing pad)

⚠ Note: This module is intended for detection purposes only and is not rated for continuous outdoor immersion. Mount the control board in a protected enclosure and expose only the sensing pad to the elements.
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