AJ-SR04M Waterproof Ultrasonic Module

AJ-SR04M Waterproof Ultrasonic Module provides a robust, industrial-grade distance measurement solution designed to operate reliably in harsh or wet environments. This specialized sensor utilizes a weather-resistant probe separated from the control electronics via a long cable, allowing for flexible mounting in outdoor or submerged conditions. Consequently, it effectively overcomes the limitations of standard ultrasonic sensors that fail when exposed to dust, moisture, or splashing water. Utilizing ultrasonic sonar technology, the module calculates distances by emitting high-frequency sound waves and measuring the time for the echo to return from a target. Furthermore, its low-power consumption and wide voltage range make it compatible with most microcontrollers like Arduino, ESP32, and Raspberry Pi. Therefore, you should choose the AJ-SR04M for projects where environmental durability and precise non-contact ranging are essential requirements.

Key Features:

• Waterproof Probe: The integrated sealed ultrasonic transducer boasts an IP65/IP67 rating, protecting the sensing element from rain, moisture, and dust ingress.
• Integrated Cable: A 2.5-meter shielded cable connects the probe to the control board, enabling remote placement of the sensor away from the processing unit.
• Multiple Output Modes: The module supports various operating modes including Trigger/Echo, Serial (UART), and PWM, which provides exceptional flexibility for different software architectures.
• High Precision: It delivers accurate distance readings with a resolution of ≈ 0.5 cm, ensuring reliable data for critical monitoring tasks.
• Wide Operating Voltage: The circuit functions efficiently between 3.0 V and 5.5 V, allowing direct interface with both 3.3 V and 5 V logic systems.

Technical Specifications:

• Operating Voltage (VCC): 3.0 V to 5.5 V DC
• Current Consumption: ≤ 30 mA (Typical)
• Sensing Range: 20 cm to 450 cm (Standard)
• Acoustic Frequency: 40 kHz
• Measurement Angle: ≤ 75°
• Resolution: ≈ 0.5 cm
• Operating Temperature: −20°C to +70°C

Mechanical Specifications:

• Probe Housing: Aluminum / Plastic Sealed Transducer
• Control Board: High-quality PCB with SMD components
• Cable Type: 2.5m Shielded PVC Cable
• Environment Protection: Probe is waterproof; control board must remain dry.

Dimensions:

• Control Board Size: ≈ 41 mm x 28.5 mm
• Probe Diameter: ≈ 22 mm
• Probe Length: ≈ 19 mm
• Cable Length: ≈ 250 cm

Pinout and Wiring:

• 5V (VCC): Connect this pin to the 3.3 V or 5 V supply of your microcontroller.
• Trig (RX): Provide a 10 µs high pulse to trigger a measurement or use as UART RX.
• Echo (TX): Measure the pulse width of this pin to determine distance or use as UART TX.
• GND: Connect to the common ground of the power supply and microcontroller.
• Wiring Note: However, ensure the connection between the probe and the board is secure before powering on to prevent damage to the transducer driver.

Datasheet Reference:

• Download AJ-SR04M Waterproof Ultrasonic Module Datasheet

Commonly Used in:

• Liquid Level Sensing: Monitoring water levels in tanks, wells, or reservoirs where humidity is high.
• Obstacle Detection: Providing proximity warnings for outdoor robots and automated guided vehicles (AGVs).
• Smart Agriculture: Measuring grain levels in silos or irrigation channel depths in outdoor fields.

Applications:

• Outdoor Parking Sensors: Detecting vehicle presence in open-air parking lots regardless of weather conditions.
• Trash Bin Monitoring: Measuring fill levels in smart waste management systems for urban environments.
• Industrial Automation: Non-contact distance measurement on production lines where dust or moisture is present.

Equivalent Models:

• JSN-SR04T: A highly similar and widely compatible waterproof ultrasonic module that uses nearly identical protocols.
• DYP-A02YY: An alternative waterproof sensor with a simplified integrated design, however, it may offer different communication interfaces.
• HC-SR04: The standard indoor version; it shares the same software logic, consequently making the AJ-SR04M a direct drop-in replacement for outdoor upgrades.

Package Includes:

• 1 x AJ-SR04M Control Board
• 1 x Sealed Waterproof Ultrasonic Probe with 2.5m Cable